DIY - Microcontroller based digital tachometer

archat68 · 28th June 2007, 10:21

Hi,
I've been looking for a tachometer for for my 2000 Zen. I learnt that good ones with shift light cost u around 2.5K. So I dived into DIY. After searching the net I decided to build the tachometer published in Siliconchip April 2000. Its designed around a PIC microcontroller and very sophisticated. You can set for work from 2 to 12 cylinder engines. Beside a digital readout you also gets a LED bargraph display which u can use as a shift light indicator. Here is the picture from the magazine:

I started with fabricating the board from plain copper clad PCB, which is the toughest part of it. After that I programmed the microcontroller with the source source code which is already available at the Siliconchip site fitted and soldered all components on the board and voila.

Its the picture of the tacho built by myself at the testing stageand tested with a 3V AC signal at the input stage and no. of cylinder set to 2. MAins AC is 50 Hz or 3000 rpm by setting the cylinder no. to 2 it gets divided by 2 by the tacho and hence the display is 1500. also note three leds glowing - each led here correspond to 500 rpm. i've set 2500 as the shift point and fitted a blue led at the 5 th led when it lights i shifts. Also the redline limit has been set to 4000, so when 4000 reches the last 3 red leds glow. However u can set the redline limit to anything between 1000 to 9900 by the three switches on the front panel. already installed in the car for more than 2 month - but looking for a decent cabinet - suggestion anyone

?
Here it goes:

The lower one is a battery monitor built by me - it indicates voltage from 12.5 to 15V with the help of a series of red - green and yellow led.
The tacho costed me 200 bucks - thanks to free sample of microcontroller and LED display given by Microchip and BIvar ( manufacturer of these components) and DIY. But should not cost more than a 1000 bucks (maximum) if all the components are purchased from the market.

So long live D-I-Y

________
Arup

tsk1979 · 28th June 2007, 10:49

All I can say is "Wow" great job.
Thats a neat little gadget you made.
But Zen is a 3 cylinder car, right?

And what is the principle behind this. i.e. where does this get the input voltage from?
I am assuming it works by measuring the residual AC in the DC voltage or something?
More details please

mainak · 28th June 2007, 11:00

that sure is a 'WOW'.
give in more details and the accuracy details on a prefitted tacho car.
great going bro !

VJ_MAVRICK · 28th June 2007, 11:08

Great work Archat and do let me know once you get the cabinet fixed and get it working in full blow ..might decide to buy from you itself

...cheers bro

abhibh · 28th June 2007, 11:13

WOW dude awesome. I am sure as soon as MANIK see's this thread you gonna get a loads of PM's

...

BTW can you also post installation pics if you have taken them ?

SRK · 28th June 2007, 11:16

That thing is really good..
By the way what goes in to connect the whole system to the car?

I mean any modifications required?

low_bass_makker · 28th June 2007, 11:26

Quote:

Originally Posted by tsk1979

All I can say is "Wow" great job.
Thats a neat little gadget you made.
But Zen is a 3 cylinder car, right?

And what is the principle behind this. i.e. where does this get the input voltage from?
I am assuming it works by measuring the residual AC in the DC voltage or something?
More details please

It is taken from the spark plug sir. and the zen is a 4 cyl car.

And archat from where did you got the electronics stuff any address or web link.

rishibravo · 28th June 2007, 11:31

wow really cool gizmo you made maan. Whats the funda behind it. Can we get a link or something .

moralfibre · 28th June 2007, 12:35

archat68, nice work and excellent DIY effort.

BUSA · 28th June 2007, 12:43

Excellent work there Arup

archat68 · 28th June 2007, 12:55

Thanks guys.
Zen is 4 cylinder. You get the input from either low voltage input at the ignition coil or from your ECU (it connects where a normal tacho connects in a car).
Here is the link for another forum where it was posted on my request:
Electronics Lab - Community

The circuit is pretty accurate. As u can see on the testing stage u get a reading of 1500 for a 1500 rpm signal fed to the input. The only con is the display increment is of 100 rm. So for rpm below 750 (say) u get 700 and for rpm above 750 u get 800 on the display.

The circuit has other feature like revv limiter output (if u have one).
So enjoy and if anybody needs any help - let me know.
_________
Arup

CrAzY dRiVeR · 28th June 2007, 20:25

WOW!

Again... but cant help it. Nice work! better pics would surely do justice to the work.

manikjeet · 28th June 2007, 23:00

wooo man that a great DIY and its my next DIY great work man

and pointer you would like to give out before i try to make it

theMAG · 28th June 2007, 23:36

Great job, archat68. This is where Indians shine - resourcefulness

low_bass_makker · 28th June 2007, 23:37

Quote:

Originally Posted by archat68

The only con is the display increment is of 100 rm. So for rpm below 750 (say) u get 700 and for rpm above 750 u get 800 on the display.

this is a minor thing but the project overall is quite nice..

28th June 2007, 10:21	#1
archat68 BHPian Join Date: Dec 2006 Location: Kolkata Posts: 905 Thanked: 642 Times	DIY - Microcontroller based digital tachometer Hi, I've been looking for a tachometer for for my 2000 Zen. I learnt that good ones with shift light cost u around 2.5K. So I dived into DIY. After searching the net I decided to build the tachometer published in Siliconchip April 2000. Its designed around a PIC microcontroller and very sophisticated. You can set for work from 2 to 12 cylinder engines. Beside a digital readout you also gets a LED bargraph display which u can use as a shift light indicator. Here is the picture from the magazine: I started with fabricating the board from plain copper clad PCB, which is the toughest part of it. After that I programmed the microcontroller with the source source code which is already available at the Siliconchip site fitted and soldered all components on the board and voila. Its the picture of the tacho built by myself at the testing stageand tested with a 3V AC signal at the input stage and no. of cylinder set to 2. MAins AC is 50 Hz or 3000 rpm by setting the cylinder no. to 2 it gets divided by 2 by the tacho and hence the display is 1500. also note three leds glowing - each led here correspond to 500 rpm. i've set 2500 as the shift point and fitted a blue led at the 5 th led when it lights i shifts. Also the redline limit has been set to 4000, so when 4000 reches the last 3 red leds glow. However u can set the redline limit to anything between 1000 to 9900 by the three switches on the front panel. already installed in the car for more than 2 month - but looking for a decent cabinet - suggestion anyone? Here it goes: The lower one is a battery monitor built by me - it indicates voltage from 12.5 to 15V with the help of a series of red - green and yellow led. The tacho costed me 200 bucks - thanks to free sample of microcontroller and LED display given by Microchip and BIvar ( manufacturer of these components) and DIY. But should not cost more than a 1000 bucks (maximum) if all the components are purchased from the market. So long live D-I-Y ________ Arup
	(1) Thanks

28th June 2007, 10:49	#2
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,695 Thanked: 23,484 Times View My Garage	All I can say is "Wow" great job. Thats a neat little gadget you made. But Zen is a 3 cylinder car, right? And what is the principle behind this. i.e. where does this get the input voltage from? I am assuming it works by measuring the residual AC in the DC voltage or something? More details please
	() Thanks

28th June 2007, 11:00	#3
mainak BHPian Join Date: Jun 2007 Location: Mumbai Posts: 90 Thanked: 0 Times	that sure is a 'WOW'. give in more details and the accuracy details on a prefitted tacho car. great going bro !
	() Thanks

28th June 2007, 11:08	#4
VJ_MAVRICK Senior - BHPian Join Date: Jun 2007 Location: Sydney Posts: 1,239 Thanked: 34 Times View My Garage	Great work Archat and do let me know once you get the cabinet fixed and get it working in full blow ..might decide to buy from you itself ...cheers bro
	() Thanks

28th June 2007, 11:13	#5
abhibh Senior - BHPian Join Date: Sep 2005 Location: Back in the HOOD near you! Posts: 2,768 Thanked: 39 Times	WOW dude awesome. I am sure as soon as MANIK see's this thread you gonna get a loads of PM's ... BTW can you also post installation pics if you have taken them ?
	() Thanks

28th June 2007, 11:16	#6
SRK Senior - BHPian Join Date: Sep 2005 Location: Mumbai Posts: 1,206 Thanked: 536 Times	That thing is really good.. By the way what goes in to connect the whole system to the car? I mean any modifications required?
	() Thanks

28th June 2007, 11:31	#8
rishibravo BHPian Join Date: Jul 2006 Location: New Delhi Posts: 579 Thanked: 12 Times View My Garage	wow really cool gizmo you made maan. Whats the funda behind it. Can we get a link or something .
	() Thanks

28th June 2007, 12:35	#9
moralfibre Team-BHP Support Join Date: Dec 2004 Location: MH-12 Posts: 8,560 Thanked: 14,440 Times	archat68, nice work and excellent DIY effort.
	() Thanks

28th June 2007, 12:43	#10
BUSA Senior - BHPian Join Date: Aug 2005 Location: Bombay Posts: 5,127 Thanked: 23 Times View My Garage	Excellent work there Arup
	() Thanks

28th June 2007, 12:55	#11
archat68 BHPian Join Date: Dec 2006 Location: Kolkata Posts: 905 Thanked: 642 Times	Thanks guys. Zen is 4 cylinder. You get the input from either low voltage input at the ignition coil or from your ECU (it connects where a normal tacho connects in a car). Here is the link for another forum where it was posted on my request: Electronics Lab - Community The circuit is pretty accurate. As u can see on the testing stage u get a reading of 1500 for a 1500 rpm signal fed to the input. The only con is the display increment is of 100 rm. So for rpm below 750 (say) u get 700 and for rpm above 750 u get 800 on the display. The circuit has other feature like revv limiter output (if u have one). So enjoy and if anybody needs any help - let me know. _________ Arup Last edited by archat68 : 28th June 2007 at 13:04.
	() Thanks

28th June 2007, 20:25	#12
CrAzY dRiVeR Team-BHP Support Join Date: Jun 2006 Location: Bangalore / TVM Posts: 18,006 Thanked: 78,833 Times View My Garage	WOW! Again... but cant help it. Nice work! better pics would surely do justice to the work.
	() Thanks

28th June 2007, 23:00	#13
manikjeet Senior - BHPian Join Date: Sep 2006 Location: chandigarh Posts: 1,617 Thanked: 296 Times View My Garage	wooo man that a great DIY and its my next DIY great work man and pointer you would like to give out before i try to make it
	() Thanks

28th June 2007, 23:36	#14
theMAG Distinguished - BHPian Join Date: May 2006 Location: Avon, CT Posts: 7,196 Thanked: 1,821 Times View My Garage	Great job, archat68. This is where Indians shine - resourcefulness
	() Thanks