Arduino based Voltmeter with Clock for Royal Enfield Thunderbird

Royal Enfield Thunderbird is one of the most cruiser styled bikes available in India. It has a twin-pod instrument cluster that houses an analog speedo and tachometer and a small LCD panel that shows the time, odo, fuel level, average speed among other things. While this would be enough for most users, I was not comfortable with the tiny display and it was difficult to look at it as the whole unit vibrates while driving. Moreover I had fitted two LED fog lamps and wanted to know the voltage across the battery when these were on. Royal Enfield classic has got an analog voltmeter that shows the battery voltage. I wanted a similar setup for my bike too. Instead of fitting an analog one, I decided to build one for myself with an arduino, few sensors and a display. So here it is, my volt ‘n’ clock display.

It shows the voltage in large font in the center. Clock on the top left and ambient temperature to the right of it. Date is shown at the bottom left with the day to the right of it. And there is a small stopwatch that starts counting in seconds and minutes once the unit starts up. All the icons are custom made and scaled down to appropriate proportions. The display is a 1.44″ LCD display commonly available online.

A video of it working in action:

List of components used:

  • Arduino Nano or its clone
  • Mini 3A voltage converter module for stepping down the 12v voltage of the motorcycle to 5v.
  • 25v voltage sensor for detecting the supply voltage.
  • I2C clock module with battery for storing and fetching the current time
  • 1.44 inch LCD display module based on I2C
  • Buzzer
  • Breadboard for testing
  • Protoboard for final soldering and assembly
  • A switchbox and plexiglass sheet for the case.
  • Handlebar clamp

The circuit being tested on a breadboard first

Breadboard testing

The icons were converted and shrunk to small sizes so that they can fit on the small display screen

A small rectangular window was cutout from an old switch box:

Switch Box

A plexiglass sheet was taken and a rectangular sheet was cutout from it for the transparent glass panel.

It was glued using super glue

The components laid out on the prototype board:

Another board on top holds the display and the buzzer. The buzzer plays a melody on starting up.

The two boards connect via connecting pins


Assembled and testing in progress

Connected the clamp to the back of the case

Final assembly and testing with an external voltmeter

Added some extra features and icons to the display

The top row shows the current time and ambient temperature. The big numeric text is the current supply voltage. The number below it is a timer that acts like a stopwatch. The bottom row shows the date and day.

Clamped the case to the bike handle

Now for the wiring part, I already had a relay for connecting my fog lamps. Connected an extra wire to the output.

That’s it. Did some testing and the system was ready to go.