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#1
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remote control extender.
"Johan Wagener" wrote in message ... I built the circuit as shown on http://www.mitedu.freeserve.co.uk/Ci...face/irext.htm. I could not get hold of the photodiodes they used in this circuit. I used the following components available from http://www.fort777.co.za/ Infra red emitter: Peak wavelength: 940nm Forward voltage at IF = 20mA: 1.6V Forward current max.: 100mA Power dissipation: 100mW Radiated angle: 30° Receiver photodiode: High sensitivity infrared photodiode in side-looking TO92 package. Black (infrared transparent) epoxy resin package. Light current typically 75uA at 1000 lux. Matching transmitter LIR151. The cathode is the short lead. ecifications Peak wavelength: 900nm Open circuit voltage: 0.35V Acceptance angle: 120° The receiving part of my circuit seems to work (led flashes when remote is used) I can't seem to get the emitting part to work. The units (tv,hi-fi, ect) simply does nothing even when the diode is placed right in front of its IR. I can's seem to find the datasheet for the SFH2030 used in the circuit Please help I assume LED0 is the IR transmitting IR LED. I suspected it may have flashed at least the once bearing in mind that you have a 27R series resistor and a power supply of 12V. This would give a current of 3-400mA, 3 to 4 times rated current. |
#2
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remote control extender.
"Johan Wagener" wrote in message
... I built the circuit as shown on http://www.mitedu.freeserve.co.uk/Ci...face/irext.htm. I could not get hold of the photodiodes they used in this circuit. I used the following components available from http://www.fort777.co.za/ Infra red emitter: Peak wavelength: 940nm Forward voltage at IF = 20mA: 1.6V Forward current max.: 100mA Power dissipation: 100mW Radiated angle: 30° Receiver photodiode: High sensitivity infrared photodiode in side-looking TO92 package. Black (infrared transparent) epoxy resin package. Light current typically 75uA at 1000 lux. Matching transmitter LIR151. The cathode is the short lead. ecifications Peak wavelength: 900nm Open circuit voltage: 0.35V Acceptance angle: 120° The receiving part of my circuit seems to work (led flashes when remote is used) I can't seem to get the emitting part to work. The units (tv,hi-fi, ect) simply does nothing even when the diode is placed right in front of its IR. I can's seem to find the datasheet for the SFH2030 used in the circuit Please help Try using a camcorder to determine if the transmitter is at least flashing. I've done this before and it works quite well. Richard |
#3
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remote control extender.
"Johan Wagener" wrote in message ... "Fred" wrote in message .. . "Johan Wagener" wrote in message ... I built the circuit as shown on http://www.mitedu.freeserve.co.uk/Ci...face/irext.htm. I could not get hold of the photodiodes they used in this circuit. I used the following components available from http://www.fort777.co.za/ Infra red emitter: Peak wavelength: 940nm Forward voltage at IF = 20mA: 1.6V Forward current max.: 100mA Power dissipation: 100mW Radiated angle: 30° Receiver photodiode: High sensitivity infrared photodiode in side-looking TO92 package. Black (infrared transparent) epoxy resin package. Light current typically 75uA at 1000 lux. Matching transmitter LIR151. The cathode is the short lead. ecifications Peak wavelength: 900nm Open circuit voltage: 0.35V Acceptance angle: 120° The receiving part of my circuit seems to work (led flashes when remote is used) I can't seem to get the emitting part to work. The units (tv,hi-fi, ect) simply does nothing even when the diode is placed right in front of its IR. I can's seem to find the datasheet for the SFH2030 used in the circuit Please help I assume LED0 is the IR transmitting IR LED. I suspected it may have flashed at least the once bearing in mind that you have a 27R series resistor and a power supply of 12V. This would give a current of 3-400mA, 3 to 4 times rated current. I did actually lose one LED because of this. It flashed quite a while before it fried. I changed the value of the resistor to 1k. That however did not solve the problem concerning the unit not emitting IR I would change this to 220R to limit the current to 50mA which should be safe. How did you see LED0, the IR led flash. Was it incandescent? I would use a video camera or a camcorder to check the output of the IR LED. |
#5
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remote control extender.
"Fred" wrote in message .. . "Johan Wagener" wrote in message ... I built the circuit as shown on http://www.mitedu.freeserve.co.uk/Ci...face/irext.htm. I could not get hold of the photodiodes they used in this circuit. I used the following components available from http://www.fort777.co.za/ Infra red emitter: Peak wavelength: 940nm Forward voltage at IF = 20mA: 1.6V Forward current max.: 100mA Power dissipation: 100mW Radiated angle: 30° Receiver photodiode: High sensitivity infrared photodiode in side-looking TO92 package. Black (infrared transparent) epoxy resin package. Light current typically 75uA at 1000 lux. Matching transmitter LIR151. The cathode is the short lead. ecifications Peak wavelength: 900nm Open circuit voltage: 0.35V Acceptance angle: 120° The receiving part of my circuit seems to work (led flashes when remote is used) I can't seem to get the emitting part to work. The units (tv,hi-fi, ect) simply does nothing even when the diode is placed right in front of its IR. I can's seem to find the datasheet for the SFH2030 used in the circuit Please help I assume LED0 is the IR transmitting IR LED. I suspected it may have flashed at least the once bearing in mind that you have a 27R series resistor and a power supply of 12V. This would give a current of 3-400mA, 3 to 4 times rated current. Infrared LEDs are often rated for a maximum of 100mA continuous forward DC current. If the circuit is working properly like it should, then the signal detected from the remote will be a roughly 38kHz 50% duty cycle squarewave carrier frequency light signal that is further modulated by the data at likely less than 50% duty cycle (of the 38kHz carrier) at some frequency well below the carrier. Usually IR remotes will AM modulate the 38kHz carrier at some frequency so slow as to be very easily human detectable as flickering. So the effective duty cycle the LED should see is likely less than 25%, but certainly well less than 50%. So even though the 27 ohm resistor limits the current to something like 3-400mA, when multiplied by the effective duty cycle the average current through the LED will likely be somewhat less than 100mA. If the circuit is operating properly, the LED will not be significantly abused... Unfortunately this circuit is very poorly designed in many respects. The circuit has novel simplicity, but pays for it in functionality/reliability and performance. If the ambient lighting conditions are too high, the circuit will constantly detect that and turn the output stage on full blast at 100% duty cycle (plain DC). Thus there certainly exists a real possibility the IR LED could be damaged by excessive current. The other really serious problem is the circuit doesn't really try very hard to keep the incomming and outgoing duty cycles the same. This is probably why the OP's implementation isn't working. While some IR receiver circuits might have lax input filters that will respond acceptably to a distorted IR signal, the OP's IR receiver probably doesn't like the distortion that likely will be added by the circuit. As a result is balks and doesn't work. A better designed IR repeater would do something more like this: An infrared 38kHz receiver IC (such as the Panansonic PNA4602M from Digikey) should first detect the remote control signal. Since the output of the receiver IC will be demodulated data, we will need to remodulate the data onto a new 38kHz carrier. Since the output of the Panasonic is an open collector output with internal pull up resistor, the output is inverted from the sent signal. We will need to invert the output signal to get it looking right again. A 38kHz 50% duty cycle (fairly high precision, +/-1kHz will likely start reducing functionality) oscillator will be needed. The oscillator output should be ANDed with the output of the inverted IR receiver IC output. The final output should be buffered by a fast switching small MOSFET such as the BSS138 to drive the LED at pulse currents of up to around 400mA (or perhaps more if you can insure the average current is less than 100mA). Using bipolar junction transistors isn't necessarily a good idea for this stage since they can have fairly long storage times which will distort the signal. At 38kHz and reasonable drive currents the effect may be minimal, but to be safe it is easier to just use a MOSFET. Make sure the range extender LED is not pointed such that any significant amount of IR light will fall on the detector, otherwise signal feedback will occur and the system will probably self oscillate. Even when going to all this trouble the range extender may still not work since the Panasonic PNA4602M or similar IR receiver IC may distort the signal enough to cause problems in some cases. In these instances probably the easiest solution to increasing range is to modify the remote control itself. Replace the IR LED with one that is more efficient (such as the Vishay TSAL6100 from Mouser), or use multiple LEDs in parallel (make sure to pump up the driver power to drive them properly). To give an idea of what is possible, using six paralleled TSAL6400 LEDs pulsed at 1A peak currents and a Vishay TSOP1256 receiver IC I was able to achieve outdoors (at night) data transmission at distances of up to an estimated 70 meters. Even more range is surely possible with shorter beam angle LEDs (or more LEDs) and perhaps some other circuit tweaks/improved optics. |
#6
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remote control extender.
would this work?
http://www.epanorama.net/documents/ir/irremote.html "Fritz Schlunder" wrote in message ... "Fred" wrote in message .. . "Johan Wagener" wrote in message ... I built the circuit as shown on http://www.mitedu.freeserve.co.uk/Ci...face/irext.htm. I could not get hold of the photodiodes they used in this circuit. I used the following components available from http://www.fort777.co.za/ Infra red emitter: Peak wavelength: 940nm Forward voltage at IF = 20mA: 1.6V Forward current max.: 100mA Power dissipation: 100mW Radiated angle: 30° Receiver photodiode: High sensitivity infrared photodiode in side-looking TO92 package. Black (infrared transparent) epoxy resin package. Light current typically 75uA at 1000 lux. Matching transmitter LIR151. The cathode is the short lead. ecifications Peak wavelength: 900nm Open circuit voltage: 0.35V Acceptance angle: 120° The receiving part of my circuit seems to work (led flashes when remote is used) I can't seem to get the emitting part to work. The units (tv,hi-fi, ect) simply does nothing even when the diode is placed right in front of its IR. I can's seem to find the datasheet for the SFH2030 used in the circuit Please help I assume LED0 is the IR transmitting IR LED. I suspected it may have flashed at least the once bearing in mind that you have a 27R series resistor and a power supply of 12V. This would give a current of 3-400mA, 3 to 4 times rated current. Infrared LEDs are often rated for a maximum of 100mA continuous forward DC current. If the circuit is working properly like it should, then the signal detected from the remote will be a roughly 38kHz 50% duty cycle squarewave carrier frequency light signal that is further modulated by the data at likely less than 50% duty cycle (of the 38kHz carrier) at some frequency well below the carrier. Usually IR remotes will AM modulate the 38kHz carrier at some frequency so slow as to be very easily human detectable as flickering. So the effective duty cycle the LED should see is likely less than 25%, but certainly well less than 50%. So even though the 27 ohm resistor limits the current to something like 3-400mA, when multiplied by the effective duty cycle the average current through the LED will likely be somewhat less than 100mA. If the circuit is operating properly, the LED will not be significantly abused... Unfortunately this circuit is very poorly designed in many respects. The circuit has novel simplicity, but pays for it in functionality/reliability and performance. If the ambient lighting conditions are too high, the circuit will constantly detect that and turn the output stage on full blast at 100% duty cycle (plain DC). Thus there certainly exists a real possibility the IR LED could be damaged by excessive current. The other really serious problem is the circuit doesn't really try very hard to keep the incomming and outgoing duty cycles the same. This is probably why the OP's implementation isn't working. While some IR receiver circuits might have lax input filters that will respond acceptably to a distorted IR signal, the OP's IR receiver probably doesn't like the distortion that likely will be added by the circuit. As a result is balks and doesn't work. A better designed IR repeater would do something more like this: An infrared 38kHz receiver IC (such as the Panansonic PNA4602M from Digikey) should first detect the remote control signal. Since the output of the receiver IC will be demodulated data, we will need to remodulate the data onto a new 38kHz carrier. Since the output of the Panasonic is an open collector output with internal pull up resistor, the output is inverted from the sent signal. We will need to invert the output signal to get it looking right again. A 38kHz 50% duty cycle (fairly high precision, +/-1kHz will likely start reducing functionality) oscillator will be needed. The oscillator output should be ANDed with the output of the inverted IR receiver IC output. The final output should be buffered by a fast switching small MOSFET such as the BSS138 to drive the LED at pulse currents of up to around 400mA (or perhaps more if you can insure the average current is less than 100mA). Using bipolar junction transistors isn't necessarily a good idea for this stage since they can have fairly long storage times which will distort the signal. At 38kHz and reasonable drive currents the effect may be minimal, but to be safe it is easier to just use a MOSFET. Make sure the range extender LED is not pointed such that any significant amount of IR light will fall on the detector, otherwise signal feedback will occur and the system will probably self oscillate. Even when going to all this trouble the range extender may still not work since the Panasonic PNA4602M or similar IR receiver IC may distort the signal enough to cause problems in some cases. In these instances probably the easiest solution to increasing range is to modify the remote control itself. Replace the IR LED with one that is more efficient (such as the Vishay TSAL6100 from Mouser), or use multiple LEDs in parallel (make sure to pump up the driver power to drive them properly). To give an idea of what is possible, using six paralleled TSAL6400 LEDs pulsed at 1A peak currents and a Vishay TSOP1256 receiver IC I was able to achieve outdoors (at night) data transmission at distances of up to an estimated 70 meters. Even more range is surely possible with shorter beam angle LEDs (or more LEDs) and perhaps some other circuit tweaks/improved optics. |
#7
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remote control extender.
"jibaro" wrote in message om... would this work? http://www.epanorama.net/documents/ir/irremote.html Well I haven't analyzed the circuit in depth, but yeah it does look like it definitely has the right idea. As the text indicates it would probably work better if it were configured for 50% duty cycle. Also, AFAIK IR remote controls more often operate with a carrier frequency of 38kHz rather than 40kHz. Certainly both frequencies along with a few others are used in IR remote applications, but I think the 38kHz is more popular. I could be wrong. Nevertheless since the 555 is a poor tolerance RC type oscillator it would probably be a good idea to use a small frequency trimming pot to allow yourself to tweak the frequency over the full range including 38kHz and 40kHz to find the frequency of best performance (and perhaps much wider range still just in case your IR remote runs at something like 56kHz for instance). Also the IR LED driver is pretty wimpy in the schematics. I would replace the output stage 2N2222 with a small MOSFET and reduce the LED series resistor substantially. The range will certainly be reduced using it as is. |
#8
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remote control extender.
Also, AFAIK IR remote controls more often operate with a carrier frequency
of 38kHz rather than 40kHz. Certainly both frequencies along with a few others are used in IR remote applications, but I think the 38kHz is more popular. I could be wrong. Philips is 36, Sony and a few others 38. I don't know who uses 40. But the bandfilters are not *that* narrow, a 38 will work reasonably well with a 36 or a 40. Wouter van Ooijen -- ------------------------------------ http://www.voti.nl PICmicro chips, programmers, consulting |
#9
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remote control extender.
"Wouter van Ooijen (www.voti.nl)" wrote in message ... Also, AFAIK IR remote controls more often operate with a carrier frequency of 38kHz rather than 40kHz. Certainly both frequencies along with a few others are used in IR remote applications, but I think the 38kHz is more popular. I could be wrong. Philips is 36, Sony and a few others 38. I don't know who uses 40. But the bandfilters are not *that* narrow, a 38 will work reasonably well with a 36 or a 40. Wouter van Ooijen -- ------------------------------------ http://www.voti.nl PICmicro chips, programmers, consulting That circuit, with minor mods for the components I had around, worked with a Panasonic DVD and a Sony TV. It refused to work with a Scientific Atlanta cable box and a Harman Kardon AVR110 system. BTW, the DVD and the AVR110 are the two components (located behind a wood door) that I want to control with this IR repeater. You could say I'm 50% there. HarmanKardon has been known to go out of its way on their designs. Could they be using a strange frenquency to carry the bitstream? Has anybody measured this? I do not have the equipment to measure, perhaps someday I will.... Thanks. |
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