Suzuki Alto RPM Meter

Introduction: Suzuki Alto RPM Meter

Maruti Suzuki alto car is a 800CC 3 cylinder engine car. it's a manual drive car , so i need to fix RPM meter for it because it doesn't come factory fitted RPM meter. So i have searched ebay and local market to find suitable one. unfortunately there is a no rpm meter for 3 cylinder. each rpm meter has 4 , 6 , 8 cylinder capacity levels. So here i have made custom RPM meter using Arduino based electronics,

Step 1: Components We Need

parts we need :

here i have not mention the parts we need for PCB etching.

Electronics parts :

Arduino nano board ( around $3 Ebay )

16x2 LCD ( $2)

2N3906 Transistor x 1

0.1 uF 25V capacitor x 1

0.1uF capacitor( code 104 ) x 1

LM 7805 regulator IC x 2 and heat sink

10K resistor x1

100Ohm resistor x 1

47K resistor x1

10K preset x 1

male and female pin headers

pcb connector


Step 2: Circuit Diagram & PCB

here i have attached a diagram and pcb design file. it was design using Dip trace software. i have attached pdf file to easy print. if not you need that software. you can connect this circuit to ignition on power line. so then meter was work only when you start your engine.

Step 3: ARDUINO Code

The Arduino code was to display large digits in a 16x2 display. i have customized code for my purpose. code was attached.before connect check the pin mapping on code. i have attached images of meter panel connector and its rpm signal wire.

Step 4: Finalizing

hope now you will create and test will work. now need to connect this circuit to car. for that we need to get rpm signal. In alto ( My one 2006 lxi ) has unused connection on its meter board. in my case i was realized why manufacturers not include the meter. because they plan to add rpm meter. thats why the send rpm data from ECU to meter panel.


Finally if you set up everything ok, then start your engine. yeah..
its work... if not double check you connections.. if need any help contact me. sorry for poor video quality. THANKS>>>>

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    8 Discussions


    Question 6 months ago on Introduction

    I'm curious about Q1, with one side being tied to ground and the base imput to the rpm signal then Q1 conducting takes the signal input of the nano to ground, does it use an internal pull up resister, I was expecting to see a resistor tied to the positive source. clearly its working i was just wondering how.


    Question 2 years ago

    hi..what meaning 5e6?

    if(rpm >= 0) { //Remove the error readings of minus values

    //Let's keep this RPM value under control, between 0 and 9999

    rpm = constrain (rpm, 0, 9999);

    if ((micros() - lastPulseTime) < 5e6 ) {

    rpm = rpm;


    Question 2 years ago on Step 5

    Will it work with Arduino nano V3? (I brought it :3) If this won't work, what are the changes I need to make? I am relatively new to this subject and have mediocre knowledge on this subject.
    I am doing this bcz I am into DIY stuff!! Please help out!!


    Answer 2 years ago

    Here i also use a nano board


    Answer 2 years ago

    Hi.. yes this work with arduino nano v3. You just need to check pin connections only..


    3 years ago

    Really nice. You could add a voltmeter too in the code and use a simple divider with resistors to get the sample.

    DIY Hacks and How Tos

    This could really interesting to have on a car. I might try this with my truck.


    Reply 4 years ago

    Thanks friend.. yeah try this.. its feel the way we drive..