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newbie:Simple LED sequence?
Hi all,
I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart |
#2
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I want to make 4 LED's light up in the following sequence (looping):
O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps... Bart How about a 1-chip solution? Teach yourself how to program a microcontroller: http://groups.google.com/group/sci.e...upply+20-bucks |
#3
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On Sat, 17 Sep 2005 13:56:04 -0400, "Bart"
wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart --- OK, here's something that'll work using a CMOS 555 and a couple of dual "D" type flip-flops: 7555 Vcc +-------+ | +--|TH R|O-+ | |___ | +-O|DIS OUT|--+ | +-------+ | | | Vcc Vcc +----[POT]---+ +-----+ | | | 1M | +----|D | | [100K] | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | GND | | +--|D | | | | | | _| | | +-|----| S|O--+ | | | _| | +----|Q R|O------+ +-----+ HC74/2 The values of your LED dropping resistors will be: Vcc - Vled R = ------------ Iled For your 9V supply, Vcc - Vled 9V - 2V R = ------------ = --------- = 350 ohms Iled 0.02A 360 ohms is a standard 5% value, so the power they each need to dissipate will be (Vcc - Vled)² (9V - 2V)² P = --------------- = ------------ ~ 0.136 watts R 360R so a standard 5% 360 ohm 1/4 watt carbon film resistor will be fine. -- John Fields Professional Circuit Designer |
#4
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On Sat, 17 Sep 2005 15:30:03 -0500, John Fields
wrote: On Sat, 17 Sep 2005 13:56:04 -0400, "Bart" wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart --- OK, here's something that'll work using a CMOS 555 and a couple of dual "D" type flip-flops: --- Oops... Forgot the ground on the power-on reset. Also, start the thing with the pot cranked to max R. The display should scroll at about one position change per second. --- 7555 Vcc +-------+ | +--|TH R|O-+ | |___ | +-O|DIS OUT|--+ | +-------+ | | | Vcc Vcc +----[POT]---+ +-----+ | | | 1M | +----|D | | [100K] | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | GND | | +--|D | | | | | | _| | | +-|----| S|O--+ | | | _| | +----|Q R|O------+ +-----+ HC74/2 The values of your LED dropping resistors will be: Vcc - Vled R = ------------ Iled For your 9V supply, Vcc - Vled 9V - 2V R = ------------ = --------- = 350 ohms Iled 0.02A 360 ohms is a standard 5% value, so the power they each need to dissipate will be (Vcc - Vled)² (9V - 2V)² P = --------------- = ------------ ~ 0.136 watts R 360R so a standard 5% 360 ohm 1/4 watt carbon film resistor will be fine. -- John Fields Professional Circuit Designer |
#5
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On Sat, 17 Sep 2005 15:37:10 -0500, John Fields
wrote: On Sat, 17 Sep 2005 15:30:03 -0500, John Fields wrote: On Sat, 17 Sep 2005 13:56:04 -0400, "Bart" wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart --- OK, here's something that'll work using a CMOS 555 and a couple of dual "D" type flip-flops: --- Oops... Forgot the ground on the power-on reset. Also, start the thing with the pot cranked to max R. The display should scroll at about one position change per second. --- 7555 Vcc +-------+ | +--|TH R|O-+ | |___ | +-O|DIS OUT|--+ | +-------+ | | | Vcc Vcc +----[POT]---+ +-----+ | | | 1M | +----|D | | [100K] | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | GND | | +--|D | | | | | | _| | | +-|----| S|O--+ | | | _| | +----|Q R|O------+ +-----+ HC74/2 The values of your LED dropping resistors will be: Vcc - Vled R = ------------ Iled For your 9V supply, Vcc - Vled 9V - 2V R = ------------ = --------- = 350 ohms Iled 0.02A 360 ohms is a standard 5% value, so the power they each need to dissipate will be (Vcc - Vled)² (9V - 2V)² P = --------------- = ------------ ~ 0.136 watts R 360R so a standard 5% 360 ohm 1/4 watt carbon film resistor will be fine. --- Crossposted to seb. -- John Fields Professional Circuit Designer |
#6
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"John Fields" schreef in bericht ... On Sat, 17 Sep 2005 15:37:10 -0500, John Fields wrote: On Sat, 17 Sep 2005 15:30:03 -0500, John Fields wrote: On Sat, 17 Sep 2005 13:56:04 -0400, "Bart" wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart --- OK, here's something that'll work using a CMOS 555 and a couple of dual "D" type flip-flops: --- Oops... Forgot the ground on the power-on reset. Also, start the thing with the pot cranked to max R. The display should scroll at about one position change per second. --- 7555 Vcc +-------+ | +--|TH R|O-+ | |___ | +-O|DIS OUT|--+ | +-------+ | | | Vcc Vcc +----[POT]---+ +-----+ | | | 1M | +----|D | | [100K] | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | GND | | +--|D | | | | | | _| | | +-|----| S|O--+ | | | _| | +----|Q R|O------+ +-----+ HC74/2 The values of your LED dropping resistors will be: Vcc - Vled R = ------------ Iled For your 9V supply, Vcc - Vled 9V - 2V R = ------------ = --------- = 350 ohms Iled 0.02A 360 ohms is a standard 5% value, so the power they each need to dissipate will be (Vcc - Vled)² (9V - 2V)² P = --------------- = ------------ ~ 0.136 watts R 360R so a standard 5% 360 ohm 1/4 watt carbon film resistor will be fine. --- Crossposted to seb. -- John Fields Professional Circuit Designer Looks good and a good explanation but... I'm missing a LED John. Or did you leave it an excercise for the OP? petrus bitbyter |
#7
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On Sat, 17 Sep 2005 16:51:15 -0500, John Fields
wrote: On Sat, 17 Sep 2005 15:37:10 -0500, John Fields wrote: On Sat, 17 Sep 2005 15:30:03 -0500, John Fields wrote: On Sat, 17 Sep 2005 13:56:04 -0400, "Bart" wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart --- OK, here's something that'll work using a CMOS 555 and a couple of dual "D" type flip-flops: --- Oops... Forgot the ground on the power-on reset. Also, start the thing with the pot cranked to max R. The display should scroll at about one position change per second. --- 7555 Vcc +-------+ | +--|TH R|O-+ | |___ | +-O|DIS OUT|--+ | +-------+ | | | Vcc Vcc +----[POT]---+ +-----+ | | | 1M | +----|D | | [100K] | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | GND | | +--|D | | | | | | _| | | +-|----| S|O--+ | | | _| | +----|Q R|O------+ +-----+ HC74/2 --- Aaarrghhh!!! I forgot the fourth LED, and the 7555's RESET is negative true... 7555 +-------+ +--|TH OUT|O-+ | |___ _| | +-O|DIS R|O----Vcc | +-------+ | Vcc | | Vcc | +----[POT]---+ +-----+ | [100K] | | | _| | | | 1M | +----|D Q| | | | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +-|----| S|O--+ | | | | _| | +-[LED]--[R]---+----|Q R|O------+ | +-----+ GND HC74/2 _ Also, a better way to run the LEDs would be off of the Q's. The starting (and running) sequence could be made the same as if they were being driven by the Q's by complementing the SETs and RESETs, but there'd no LED loads on the Q's and, consequently, no problem with logic input thresholds being load dependent. Wire it up the way it's shown and if you have problems with it, post back and I'll be happy to help you get it right. -- John Fields Professional Circuit Designer |
#8
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Hi,
I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O Ok I see your up on the 555 so I would say you should use a 555 to generate the clock (And yes, a pot would make it so you could alter the speed) and then for it to drive a decade counter. Put two diodes from each output so when number 0 was selected by the counter the two diodes would go to LED 1 and 2, number 1 would have two diodes running to 2 and 3, etc. I see you only want an 4 event counter so tie output 4 to the reset line. it would go something like this: LED1 LED2 LED3 LED4 output 0 D D Output 1 D D Output 2 D D Output 3 D D Output 4 reset line. You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Good luck Oliver Hannaford-Day Lichfield Electronics |
#9
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On Sat, 17 Sep 2005 18:09:58 -0500, John Fields
wrote: Aaarrghhh!!! I forgot the fourth LED, and the 7555's RESET is negative true... 7555 +-------+ +--|TH OUT|O-+ | |___ _| | +-O|DIS R|O----Vcc | +-------+ | Vcc | | Vcc | +----[POT]---+ +-----+ | [100K] | | | _| | | | 1M | +----|D Q| | | | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +-|----| S|O--+ | | | | _| | +-[LED]--[R]---+----|Q R|O------+ | +-----+ GND HC74/2 Also, a better way to run the LEDs would be off of the Q's. The starting (and running) sequence could be made the same as if they were being driven by the Q's by complementing the SETs and RESETs, but there'd no LED loads on the Q's and, consequently, no problem with logic input thresholds being load dependent. Wire it up the way it's shown and if you have problems with it, post back and I'll be happy to help you get it right. --- More problems. HC74's aren't supposed to run on 9V, so you'd have to use something like a 78L05 to get that 9V down to 5V if you used HCMOS, and recalculate the LED series R's. -- John Fields Professional Circuit Designer |
#10
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"John Fields" schreef in bericht ... On Sat, 17 Sep 2005 18:09:58 -0500, John Fields wrote: Aaarrghhh!!! I forgot the fourth LED, and the 7555's RESET is negative true... 7555 +-------+ +--|TH OUT|O-+ | |___ _| | +-O|DIS R|O----Vcc | +-------+ | Vcc | | Vcc | +----[POT]---+ +-----+ | [100K] | | | _| | | | 1M | +----|D Q| | | | | | | _| | | [1µF] +------| S|O------+----+ | | | | _| | | | | | | +--|Q R|O--+ | [0.1µF] | | | | +-----+ | | | | | | | HC74/2 | | GND +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O------+ | | | | _| | | | | | +--|Q R|O--+ | | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +------| S|O--+ | | | | | _| | | | | | +--|Q R|O------+ | | | | +-----+ | | | | | | HC74/2 | | +-[LED]--[R]-----+ | | | | | | | | | | | | +-----+ | | | | | +--|D | | | | | | | _| | | | +-|----| S|O--+ | | | | _| | +-[LED]--[R]---+----|Q R|O------+ | +-----+ GND HC74/2 Also, a better way to run the LEDs would be off of the Q's. The starting (and running) sequence could be made the same as if they were being driven by the Q's by complementing the SETs and RESETs, but there'd no LED loads on the Q's and, consequently, no problem with logic input thresholds being load dependent. Wire it up the way it's shown and if you have problems with it, post back and I'll be happy to help you get it right. --- More problems. HC74's aren't supposed to run on 9V, so you'd have to use something like a 78L05 to get that 9V down to 5V if you used HCMOS, and recalculate the LED series R's. -- John Fields Professional Circuit Designer Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de petrus bitbyter |
#11
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hi!.. try this one!... its,
http://www.tpub.com/automotive.htm the link provide infos readring music and more!... Bart wrote: Hi all, I want to make 4 LED's light up in the following sequence (looping): O O _ _ _ O O _ _ _ O O O _ _ O O O _ _ _ O O _ _ _ O O O _ _ O the above shows it has gone through two sequences, I'll want it to be continuous and with variable frequency (a potentiometer?) I've read up on 555 oscillators, logic gates (nand, nor, etc.), flip-flops, op-amps.......... I don't know where to start. I DO have a nine volt battery and some LEDs. Any guidance is greatly appreciated, Bart |
#12
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On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter"
wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer |
#13
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Hi I would have used a 555 with a binary up down counter.
"John Fields" wrote in message ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer |
#14
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On Mon, 19 Sep 2005 14:35:02 GMT, "eric"
wrote: Hi I would have used a 555 with a binary up down counter. --- To do what? -- John Fields Professional Circuit Designer |
#15
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"John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). Alexander A.C.E. (Applied Communications Engineer) |
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On Mon, 19 Sep 2005 17:42:01 +0200, "Alexander"
wrote: "John Fields" schreef in bericht .. . On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? --- Yes, of course. Why shouldn't I? --- Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). --- Sounds vaguely patronizing. What do you mean? -- John Fields Professional Circuit Designer |
#17
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"John Fields" schreef in bericht news On Mon, 19 Sep 2005 17:42:01 +0200, "Alexander" wrote: "John Fields" schreef in bericht . .. On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? --- Yes, of course. Why shouldn't I? --- Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). --- Sounds vaguely patronizing. What do you mean? -- John Fields Professional Circuit Designer I didn't mean it as patronizing just as fun. As more experienced designers we might more easily add a programmable device. Someone who just starts cannot do this because the programming is too difficult. I sometimes see a beginner add several chips with a cost of $15 or more which can easily be replaced by one FPGA or MicroController with a total cost of $5, and this makes the design also more flexible. |
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On Mon, 19 Sep 2005 20:26:32 +0200, "Alexander"
wrote: "John Fields" schreef in bericht news On Mon, 19 Sep 2005 17:42:01 +0200, "Alexander" wrote: "John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? --- Yes, of course. Why shouldn't I? --- Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). --- Sounds vaguely patronizing. What do you mean? -- John Fields Professional Circuit Designer I didn't mean it as patronizing just as fun. As more experienced designers we might more easily add a programmable device. Someone who just starts cannot do this because the programming is too difficult. I sometimes see a beginner add several chips with a cost of $15 or more which can easily be replaced by one FPGA or MicroController with a total cost of $5, and this makes the design also more flexible. --- I understand the fascination with microcontrollers, but in an application where one isn't warranted, it's just wasteful to design one in. Consider the OP's application, a simple four-position marquee scroller, and it becomes evident (to me, anyway) that $1 for a PIC VS about fifty cents' worth of glue logic for the same function makes the PIC unattractive. Plus, even with a free programmer and development system there's still the learning curve to climb. -- John Fields Professional Circuit Designer |
#19
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"Alexander" schreef in bericht ... "John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). Alexander A.C.E. (Applied Communications Engineer) So why shouldn't he call himself a Professional Circuit Designer? He often contributes circuits in the electronics newsgroups. PIC10F2xx will be suitable for fixed frequency. I'd go for a 12F675 because there's no need for extra components but one potentiometer for the variable frequency that was asked for. The point is however that the OP seems to have hardly any skills in electronics so I doubt whether he can reed the schematics we provided. That's not to blame the OP. After all this is a "basics" group so he put a good question on the right place. But that's also why I try to keep it as simple as possible and leave it to the OP to ask further if he needs to. petrus bitbyter |
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"Alexander" schreef in bericht ... "John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). Alexander A.C.E. (Applied Communications Engineer) So why shouldn't he call himself a Professional Circuit Designer? He often contributes circuits in the electronics newsgroups. PIC10F2xx will be suitable for fixed frequency. I'd go for a 12F675 because there's no need for extra components but one potentiometer for the variable frequency that was asked for. The point is however that the OP seems to have hardly any skills in electronics so I doubt whether he can reed the schematics we provided. That's not to blame the OP. After all this is a "basics" group so he put a good question on the right place. But that's also why I try to keep it as simple as possible and leave it to the OP to ask further if he needs to. petrus bitbyter |
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"Alexander" schreef in bericht ... "John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). Alexander A.C.E. (Applied Communications Engineer) So why shouldn't he call himself a Professional Circuit Designer? He often contributes circuits in the electronics newsgroups. PIC10F2xx will be suitable for fixed frequency. I'd go for a 12F675 because there's no need for extra components but one potentiometer for the variable frequency that was asked for. The point is however that the OP seems to have hardly any skills in electronics so I doubt whether he can reed the schematics we provided. That's not to blame the OP. After all this is a "basics" group so he put a good question on the right place. But that's also why I try to keep it as simple as possible and leave it to the OP to ask further if he needs to. petrus bitbyter |
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John Fields wrote:
On Mon, 19 Sep 2005 20:26:32 +0200, "Alexander" wrote: "John Fields" schreef in bericht news On Mon, 19 Sep 2005 17:42:01 +0200, "Alexander" wrote: "John Fields" schreef in bericht m... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? --- Yes, of course. Why shouldn't I? --- Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). --- Sounds vaguely patronizing. What do you mean? -- John Fields Professional Circuit Designer I didn't mean it as patronizing just as fun. As more experienced designers we might more easily add a programmable device. Someone who just starts cannot do this because the programming is too difficult. I sometimes see a beginner add several chips with a cost of $15 or more which can easily be replaced by one FPGA or MicroController with a total cost of $5, and this makes the design also more flexible. --- I understand the fascination with microcontrollers, but in an application where one isn't warranted, it's just wasteful to design one in. Consider the OP's application, a simple four-position marquee scroller, and it becomes evident (to me, anyway) that $1 for a PIC VS about fifty cents' worth of glue logic for the same function makes the PIC unattractive. Plus, even with a free programmer and development system there's still the learning curve to climb. It was another damn "use a PIC" post. Some of these posters drive me crazy. Never a "Wow John, you sure put a lot of work into that, nice job!" Never a complete project, with a schematic and source code. Just "you could use a PIC". Hell, if you did what those pic-ophiles do, your posts would say "use a soldering iron." One thing's for sure - we can't criticize the PIC designs posted as solutions to requests from posters. I'll tell you this, I'll put any one of the solutions you've offered in the newsgroup against all of the posted "PIC solutions", combined. Your solutions are always great. Theirs are non-existant. Ed |
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On Tue, 20 Sep 2005 00:57:30 GMT, ehsjr
wrote: John Fields wrote: --- I understand the fascination with microcontrollers, but in an application where one isn't warranted, it's just wasteful to design one in. Consider the OP's application, a simple four-position marquee scroller, and it becomes evident (to me, anyway) that $1 for a PIC VS about fifty cents' worth of glue logic for the same function makes the PIC unattractive. Plus, even with a free programmer and development system there's still the learning curve to climb. It was another damn "use a PIC" post. Some of these posters drive me crazy. Never a "Wow John, you sure put a lot of work into that, nice job!" Never a complete project, with a schematic and source code. Just "you could use a PIC". Hell, if you did what those pic-ophiles do, your posts would say "use a soldering iron." One thing's for sure - we can't criticize the PIC designs posted as solutions to requests from posters. I'll tell you this, I'll put any one of the solutions you've offered in the newsgroup against all of the posted "PIC solutions", combined. Your solutions are always great. Theirs are non-existant. Ed --- Thanks! :-) -- John Fields Professional Circuit Designer |
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ehsjr wrote:
It was another damn "use a PIC" post. Some of these posters drive me crazy. Never a "Wow John, you sure put a lot of work into that, nice job!" Never a complete project, with a schematic and source code. Just "you could use a PIC". Hell, if you did what those pic-ophiles do, your posts would say "use a soldering iron." One thing's for sure - we can't criticize the PIC designs posted as solutions to requests from posters. I'll tell you this, I'll put any one of the solutions you've offered in the newsgroup against all of the posted "PIC solutions", combined. Your solutions are always great. Theirs are non-existant. Agreed. I could probably have made a movie of it in the time it would take a PIC-er to just get started! Here it is: http://www.terrypin.dial.pipex.com/I...quencer4MB.wmv -- Terry Pinnell Hobbyist, West Sussex, UK |
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"petrus bitbyter" schreef in bericht l... "Alexander" schreef in bericht ... "John Fields" schreef in bericht ... On Sun, 18 Sep 2005 23:22:03 +0200, "petrus bitbyter" wrote: Once you have a 555 clock running you can hook up an old CD4013B like drawn below. This type of components runs on power supplies from 3 to 20V. Of course you have at least one problem left as these type of components can sink only a few mA of current. So your LEDs will be pretty dim or you have to use high efficiency LEDs. The series resistors can also be much lower then calculated as the outputs have an internal resistor inside. The best thing you can do is using an extra IC, a CD4050B. This one contains six buffers which are able to sink enough current to drive a LED. Vcc 3-20V +-----+-----+-----+----- | | | | .-. .-. .-. .-. | | | | | | | | | | | | | | | | '-' '-' '-' '-' | | | | | | | | V V V V - - - - | | | | | | | | | +--------+ | | | | | | | +--------------+ .----. | | .---- | | +-----|D0 Q|---+--|-----|D1 Q|---+ | | | _| | | _| | | +--| Q|o-----+ +--| Q|o-----+ | | '----' | '----' | | | CD4013B(a) | CD4013B(b) | Clock | | | | ----------+-----------------+ | | | +-----------------------------------+ --- Ah, yes... the quadrature encoder! Good one! It didn't even cross my mind. I must be slipping... -- John Fields Professional Circuit Designer And You call yourself a Professional Circuit Designer??? Ok, most of the time we have solutions that are not suitable for a beginner (PIC 10F series?). Alexander A.C.E. (Applied Communications Engineer) So why shouldn't he call himself a Professional Circuit Designer? He often contributes circuits in the electronics newsgroups. PIC10F2xx will be suitable for fixed frequency. I'd go for a 12F675 because there's no need for extra components but one potentiometer for the variable frequency that was asked for. The point is however that the OP seems to have hardly any skills in electronics so I doubt whether he can reed the schematics we provided. That's not to blame the OP. After all this is a "basics" group so he put a good question on the right place. But that's also why I try to keep it as simple as possible and leave it to the OP to ask further if he needs to. petrus bitbyter Exactly some people take to soon a PIC, GAL, FPGA or any other device. Most of the times this are more experienced people who need a flexible design or know that in the future the design could get more functions. I had a simple design, when it was finished and in production for half a year, the customer wanted a redesign with a lot more functions. All it took was 2 days of programming and debugging. The PCB didn't change although the customer thought it did . Alexander |
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On Tue, 20 Sep 2005 21:51:08 +0200, "Alexander"
wrote: Exactly some people take to soon a PIC, GAL, FPGA or any other device. Most of the times this are more experienced people who need a flexible design or know that in the future the design could get more functions. I had a simple design, when it was finished and in production for half a year, the customer wanted a redesign with a lot more functions. --- Had you known what you were doing and optimized your customer's requirements in the first place, the second effort would not have been necessary. However, since two extra days' worth of programming and debugging were needed because of your stupidity and your client's inability to sort it all out, you got a nice fat check. No? -- John Fields Professional Circuit Designer |
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On Tue, 20 Sep 2005 17:06:27 -0500, John Fields
wrote: On Tue, 20 Sep 2005 21:51:08 +0200, "Alexander" wrote: Exactly some people take to soon a PIC, GAL, FPGA or any other device. Most of the times this are more experienced people who need a flexible design or know that in the future the design could get more functions. I had a simple design, when it was finished and in production for half a year, the customer wanted a redesign with a lot more functions. --- Had you known what you were doing and optimized your customer's requirements in the first place, the second effort would not have been necessary. However, since two extra days' worth of programming and debugging were needed because of your stupidity and your client's inability to sort it all out, you got a nice fat check. No? --- Sorry, that was uncalled for. -- John Fields Professional Circuit Designer |
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"John Fields" schreef in bericht ... On Tue, 20 Sep 2005 17:06:27 -0500, John Fields wrote: On Tue, 20 Sep 2005 21:51:08 +0200, "Alexander" wrote: Exactly some people take to soon a PIC, GAL, FPGA or any other device. Most of the times this are more experienced people who need a flexible design or know that in the future the design could get more functions. I had a simple design, when it was finished and in production for half a year, the customer wanted a redesign with a lot more functions. --- Had you known what you were doing and optimized your customer's requirements in the first place, the second effort would not have been necessary. However, since two extra days' worth of programming and debugging were needed because of your stupidity and your client's inability to sort it all out, you got a nice fat check. No? --- Sorry, that was uncalled for. -- John Fields Professional Circuit Designer So was my remark several post ago. The fact was that I anticipated the client's inablity to know what he wanted. So I build it the way I could easily adapt it for his future needs. As A mattor of Facts I suggested the sings he later wanted in the first place, but NO way listen! And Yes there was a nice fat check!!! Alexander |
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On Sun, 18 Sep 2005 16:48:48 +0100, "Oliver Hannaford-Day"
wrote: You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Have you actually done that? Seems more likely the transistor would gradually rise into conduction as the base voltage climbed to .6 volts or so. At that point it would limit the voltage from rising further, but not discharge the cap . . . What you propose (a relaxation oscillator) would probably take more than one transistor, or an Thryistor or Unijunction transistor. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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On Sat, 17 Sep 2005 13:56:04 -0400, "Bart" wrote:
Four 555's or two dual 555's or a quad monostable timer would work. The falling output of one 555 is ac coupled into the next (the datasheet shows how with a cap and two pull up resistors) The outputs from the 555's are steered to two LED's via some diodes. -- ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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On 2005-10-03, default wrote:
On Sun, 18 Sep 2005 16:48:48 +0100, "Oliver Hannaford-Day" wrote: You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Have you actually done that? Seems more likely the transistor would gradually rise into conduction as the base voltage climbed to .6 volts or so. At that point it would limit the voltage from rising further, but not discharge the cap . . . use common collector configuration, (aka emitter follower) What you propose (a relaxation oscillator) would probably take more than one transistor, or an Thryistor or Unijunction transistor. I think the plan was a delay after the button is released. -- Bye. Jasen |
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On Wed, 5 Oct 2005 18:23:53 +1300, Jasen Betts
wrote: On 2005-10-03, default wrote: On Sun, 18 Sep 2005 16:48:48 +0100, "Oliver Hannaford-Day" wrote: You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Have you actually done that? Seems more likely the transistor would gradually rise into conduction as the base voltage climbed to .6 volts or so. At that point it would limit the voltage from rising further, but not discharge the cap . . . use common collector configuration, (aka emitter follower) --- Really? Post a schematic for a single transistor emitter follower astable multivibrator, OK? --- What you propose (a relaxation oscillator) would probably take more than one transistor, or an Thryistor or Unijunction transistor. I think the plan was a delay after the button is released. --- I think you've got your threads mixed up. This one was for a scrolling display and I don't recall the mention of any kind of button... -- John Fields Professional Circuit Designer |
#33
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On 2005-10-05, John Fields wrote:
On Wed, 5 Oct 2005 18:23:53 +1300, Jasen Betts wrote: On 2005-10-03, default wrote: On Sun, 18 Sep 2005 16:48:48 +0100, "Oliver Hannaford-Day" wrote: You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Have you actually done that? Seems more likely the transistor would gradually rise into conduction as the base voltage climbed to .6 volts or so. At that point it would limit the voltage from rising further, but not discharge the cap . . . use common collector configuration, (aka emitter follower) --- Really? Post a schematic for a single transistor emitter follower astable multivibrator, OK? maybe something could be done using a transformer I think the plan was a delay after the button is released. I think you've got your threads mixed up. This one was for a scrolling display and I don't recall the mention of any kind of button... yeah... you're right. I thought we were talking dice... Bye. Jasen |
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On Fri, 7 Oct 2005 21:10:30 +1300, Jasen Betts
wrote: On 2005-10-05, John Fields wrote: On Wed, 5 Oct 2005 18:23:53 +1300, Jasen Betts wrote: On 2005-10-03, default wrote: On Sun, 18 Sep 2005 16:48:48 +0100, "Oliver Hannaford-Day" wrote: You could scrap the 555 for a variable resistor hooked to a capacitor and transistor, the resistor would mean the cap would charge slowly (And as such the voltage would climb slowly) until the voltage was such to activate the transistor which would ground the cap and restart the sequence.. a nice simple oscillator for you. :-) Have you actually done that? Seems more likely the transistor would gradually rise into conduction as the base voltage climbed to .6 volts or so. At that point it would limit the voltage from rising further, but not discharge the cap . . . use common collector configuration, (aka emitter follower) --- Really? Post a schematic for a single transistor emitter follower astable multivibrator, OK? maybe something could be done using a transformer --- That would be more properly called a 'blocking oscillator'. -- John Fields Professional Circuit Designer |
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