Introduction: Rear Matrix Bike Light

Hi everyone! I have always been fascinated by LEDS and way they glow, its just so mesmerizing, especially the matrix 8 x 8 and RGB led strips .I have wanted to build a rear bike light for my bicycle for a long time and now that i am able to build one, i want to share my project with everyone so that you can build your own cool rear bike light!!! If you like this project do support it by dropping a vote for it in the "Lighting Challenge".

Step 1: Supplies

The supplies needed for this instructable is pretty easy to get.

A. Arduino board

B. 8 x 8 matrix module with MAX7219 LED driver chip

C. 5 Male-to-female jumper wires

D. 2 Male-to-male jumper wires

E. 3.7 V 300mAh battery or a small rechargeable battery with 3.7V or a tiny powerbank.

F. ON/ OFF Switch

G. Single rectangular case box.

H. Transparent double sided tape

I. 2 Cable ties

Step 2: Arduino IDE

After gathering all the parts needed, we will be uploading the code needed to run this build.

The code is given above. its pretty easy to understand.Make sure you have chosen the correct port before uploading the code.

Step 3: Wiring

Part A

The matrix 8 x 8 module has 5 pins on each side. The pin setup are given below with the schematic as well.



DIN- Digital Pin 12

CS- Digital Pin 11

CLK - Digital pin 10

Part B

After part A is complete then we will be connecting the battery and the switch to the Arduino

The positive terminal of the switch will be connected to positive terminal of the battery.

And the negative terminal of the switch will be connected to the 5V of the Arduino whereas the negative terminal of the battery will be connected to GND of the Arduino board.

Part C

Now when you turn on the switch to the ON side the Arduino board will be powered by the battery and the Matrix 8 x 8 module should light up as well.

Step 4: Assembly

Now fit all the components to the Case.Fortunately the case was the perfect size for this build, alternatively you could use any tiny box which can easily fit all the components .I used double sided transparent tape to fix the Arduino broad and the matrix 8 x 8 module in one place so that they don't move around when i am riding my bike. I have put the switch outside the case for easy access.

I added cable-ties and double sided transparent tape below the bike seat so that case is tightly fixed and doesn't move while going through bums and rough roads.

Step 5: Improvements and Upgrades

I am quite proud of this build but there is still lot of room for improvement. For example I would put the case in such a way that it is more visible(More upright instead of slanting) but unfortunately my bicycle frame doesn't allow that.

You could also add a Bluetooth module which you can directly control using your smartphone and you could even add animations (Turn signals and so on)

The possibilities are ENDLESS!!!

The battery life is prefect!!! I used the battery for my broken drone. The battery stays for almost 2 Hours with max brightness and all LEDS turned on.


Also here is my email if you want to contact regarding this project -

If you like this project do support it by dropping a vote for it in the "Lighting Challenge".

Lighting Challenge

Participated in the
Lighting Challenge