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#1
Posted to alt.electronics,sci.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
Anyone have a simple digital tachometer schematic handy?
I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. |
#2
Posted to alt.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
Noozer wrote:
Anyone have a simple digital tachometer schematic handy? I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. ============================================ try epanorama. This would also be a good project to learn c programming on a microcontroller. Use a text lcd as the bar graph. Or a graphics lcd. Look at the Olimex MT128 at olimex.com |
#3
Posted to alt.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
Noozer wrote:
Anyone have a simple digital tachometer schematic handy? I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. How about doing it the old-fashioned analog way ? An LM2907/2917 as F-V converter, and a 4 1/2-digit DVM module for readout. Another venerable IC, the LM3914 could provide the bar graph display, two of them for a 20-dot scale. |
#4
Posted to alt.electronics,sci.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
"Noozer" wrote in message news:GmQ0h.206269$5R2.25840@pd7urf3no... Anyone have a simple digital tachometer schematic handy? I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. http://www.siliconchip.com.au/cms/A_102835/article.html A Digital Tachometer For Your Car Compact design features a 4-digit LED display and a bargraph. It can also provide gearchange indication and drive a rev limiter. |
#5
Posted to alt.electronics,sci.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
"Noozer" wrote in message news:GmQ0h.206269$5R2.25840@pd7urf3no... Anyone have a simple digital tachometer schematic handy? I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. Build a frequency counter, and pick the right gate time. I think if you make the gate time 1/300 of a minute, the display will show RPM/100. Make it 1/30th of a minute (2seconds), and it will display RPM/10. There is a common coil? Tam |
#6
Posted to alt.electronics,sci.electronics,sci.electronics.basics,sci.electronics.design
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Digital automotive tach circuit?
On Sun, 29 Oct 2006 22:03:50 -0500, "Tam/WB2TT"
wrote: "Noozer" wrote in message news:GmQ0h.206269$5R2.25840@pd7urf3no... Anyone have a simple digital tachometer schematic handy? I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine. Fed by the TACH output of a six cylinder GMC on distributor coil. If it isn't much more difficult, I'd like to be able to drive a bar graph of 12 to 16 LEDs as well. Build a frequency counter, and pick the right gate time. I think if you make the gate time 1/300 of a minute, the display will show RPM/100. Make it 1/30th of a minute (2seconds), and it will display RPM/10. There is a common coil? Tam That's too obvious. I'd stuff a down counter with a preloaded number corresponding to some very high RPM then use the tach signal to gate a series of pulses from a crystal oscillator into the counter. Sort of measuring period, but displaying RPM . . . Requires some latching/gating to display the count while the next count is being acquired. Main advantages: capable of very high resolution and fast response, with low pulses per revolution. The concept works; I had it bread boarded and up. An analog display was more intuitive and I could acquire the RPM in a millisecond glance, so used analog instead. Digital displays make more sense in slow flying aircraft IMHO. ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-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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