With this MOD, an EUC using MicroWorks 30B4 controller board will have a RGB LED strip that will turn red when the rides brakes (STOP light) and will make an animation with color that increases in speed when the EUC speed increases - please see the video:

Video "EGG Electric Unicycle - promotion at Makerfaire Lisbon 2016": https://youtu.be/GVwIKUGX1u8

Riding an EUC during the night is much more cool if it has lights (important for safety reasons!) but is is even more cool if the lights have color and they can work as a brake STOP light, increase the animation speed with the EUC speed, etc.

The MicroWorks 30B4 board have a Bluetooth module and the EUC information like speed, battery voltage e motor current is always sent out every 200ms, to the module, by UART. We can read the information at the TX pin of UART and use it for our needs.

On this MOD I used an cheap Arduino Pro Mini to read and process the data from TX pin of UART. Then I controlled a cheap RGB LED strip model WS2812b with 15 RGB LEDs.

For the power supply, I used the MicroWorks 60V to 12V step down converter (modded to output 5V). As the WS2812b and Arduino need 5V, I used the step down converter with 5V output. The max current the WS2812b with the 15 LEDs and the Arduino sink should be under 1A and so is ok for step down converter that can handle max of 2A.
I used a switch to turn on/off the power supply (at the input of the step down converter).

As showing on the following picture, I used a small board to fix the original Bluetooth module (from the 30B4 controller board) together with the Arduino and the step down converter. I also added 3 connectors: 1 for the 60V power supply coming from the main board; 1 for the on/off switch and the last one for the WS2812b RGB LED strip:

The following picture shows the final assembly on the EGG EUC, including the WS2812b RGB LED strip that were glued with hotmelt glue to the plastic shell:

Please find the firmware for the Arduino here: https://github.com/EGG-electric-unicycle/RGB_LED_bar/blob/master/RGB_led_bar/RGB_led_bar.ino

You can see more information about the MicroWorks 30B4 controller board here: MicroWorks-30B4-30kmh-controller-board-with-bluetooth

Component	Units	Price Unit ($)	Link	Notes
Arduino Pro Mini	1	1.5	http://www.ebay.com
ws2812b RGB LED strip (15 LED)	1	12	http://www.ebay.com
MicroWorks 60V to 12V step down converter	1	12	http://wholesaler.alibaba.com/product-detail/converter-DC-60V-to-12V-output_60461417441.html
TOTAL	$25.5	-	-