DIY bike tachometer

I will show you how to build a bike speedometer. It shows your speed,
the average speed,the temperature, the trip time and the total distance. You can change it using the button. Additionally, the speed is shown on a tachometer. I built it because I like building new things, I have not found anything like this on the internet so I want to show you how to build a good speedometer as the one on my bike is not as cool as I want 🙂 . So let’s get started.

Step 1: Parts:

This is a list of parts that you will need. They cost me about $ 40 but I bought them in Poland.


-bike with reed switch

-LCD display 16×2


DIY bike tachometer


-thermometer DS18B20

-resistor 1.2k Ω , 4.7k Ω



-potentiometer 10 kΩ

-9V battery



-tools (drill, soldering, knife, tape)

Step 2: Connection

I added a picture from Fritzing and verbal description of how to connect it. In the picture all red wires are connected to 5V, all blue cables are connected to GND.

  • LCD display:

VSS –> GND Arduino

VDP –> 5V Arduino

VO –> output potentiometer (potentiometer VCC -> 5V Arduino, potentiometer GND -> Arduino GND).

RS –> pin 12 Arduino

RW –> GND Arduino

E –> pin 11 Arduino

D4 –> pin 5 Arduino

D5 –> pin 4 Arduino

D6 –> pin 3 Arduino

D7 –> pin 2 Arduino

A –> 5V Arduino

K –> GND Arduino

  • Servo:

VCC –> 5V Arduino

mass –> GND Arduino

Data –> pin 6 Arduino

  • Thermometer:

VCC –> 5V Arduino

mass –> GND Arduino

Data –> pin 1 Arduino

data and power is connected via a 4.7 kΩresistor

  • Sensor on wheel:

one end -> 5V Arduino

second end -> A0 Arduino and resistor 1,2 kΩ

The other end of the resistor to ground in the Arduino

  • Button:

one end –> 5V Arduino

second end –> A1 Arduino

Step 3: Upload code:

Below I added the code in comments there is an explanation.

links to the download libraries:

If you have a different wheel diameter you have to change it. You can calculate it with this formula:

circuit = π*d*2,54 (d=diameter of your wheel, I multiplied it by 2.54 to get the result in meters).


For more detail: DIY bike tachometer

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