73' VW Beetle Tachometer & Oil Temp Sensor

Old VW beetles do not have either an oil temp sensor or tachometer. Because of this when driving you do not know if your engine is overheating, or whether you are over raving the engine.

Comment 1

Inspiration

 I got a 73' VW beetle as my first car, and right off the bat I started missing some of the features that came as standard in the cars I had learned to drive. The car was missing essential sensors such as the RPM and engine oil temp.

What it does

 The device measures/ displays the speed of the engine (RPM) and the temperature of the engine oil.

How I built it

The base of the project is an Arduino nano, a very small yet capable microprocessor. In addition to the Arduino I used a couple open source sensors and a 16bit display. In order to measure the revolutions per minute of the engine (engine RPM) I made use of a Hall effect sensor. This sensor, simply put, is a switch that turns on/off whenever a magnetic field is applied. I installed the sensor, and a magnet to the flywheel of the engine. Every time the engine turned the switch would be activated, and by measuring how many times the switch was activated you could measure RPM. In addition to the RPM I wanted to measure the temperature of the engine oil so that I could know if the engine was overheating. In order to install the sensor I had to make an adapter so that I could use an existing port on the engine block. I installed the sensor into the adapter and made sure it did not leak.

Challenges I ran into

Because of how fast the engine flywheel spins, and the tight tolerances it was very difficult to keep the magnet attached at high RPM 
The adapter for the oil sensor had to go through 2 iterations, the first consisted of high temperature glue, which in initial tests leaked way too much, so I decided to sacrifice some time to make a more reliable one with welded metal.

Accomplishments that I'm proud of

I am proud of the code for the RPM sensor, because it was very hard to smooth the data from the sensor in a way that would make it look good

What I learned

I learned how to use the arduino 16bit display library, as well as how to use a Hall effect sensor in order to measure RPM

What's next for 73' VW Beetle Tachometer & Oil Temp Sensor

I am going to install a wheel speed sensor in order to measure the speed at which the car is moving because the speedometer that the car came with is almost 50 years old and is not very accurate.

Built With

Share this project:

Updates