Johannes' Blog

Recently, I have been asked by Farnell if I were interested in taking part in their free product road test program. As I like tinkering with electronics stuff, I said yes and chose the STM32F4-Discovery board as an item to test.



The STM32F4-Discovery board is little development/evaluation board from ST to promote their STM32F4 micro controller series. The STM32F407 on the Discovery board consists of a 32 bit Corex-M4F ARM processor (which can run at up to 168 MHz), 192 kB of RAM (112+16+64 kB), 1 MB of flash memory and lots of peripherals (timers, DMA controllers, DACs, ADCs, two USB OTG ports, ...) and of course lots of general purpose I/O pins.

Introduction

This is an IKEA SPÖKA light. It is a small night light resembling a little ghost.



Originally powered by an internal rechargable battery, the light is controlled by a single button. When pressing that button it starts cycling through various color combintations. When you press that button again it freezes the current color. That's all it can do. Depending on the model the colors can be a combination of either blue and green or red, orange and blue.

Inspired by another SPÖKA mod I decided to also modify such a light, but instead of wirelessly communicating with the device, I wanted to be able to control it through USB. As the power requirements of the SPÖKA light are very low, it can easily be powered through the USB as well.