reverse engineer LED dimmer/flasher ?

[jmelson]

Has anybody reverse-engineered the 3-button flasher/dimmer module that is sold with LED strips?  It has an Atmel 24C02 EEPROM (2 KB) and an SOIC chip with no label.  But, with an EEPROM on there, it seems it has to be some common microcontroller.  Then, there are 3 paralleled Si2302DS MOSFETs to power the LEDs.

I've attached photos of the module as supplied, and with the heat shrink cover removed, fromt and back.

Thanks for any info anyone can provide.

Jon

[TomS_]

At a guess, the EEPROM may hold data used to adjust the brightness of the LEDs at some point in a display pattern. That way the micro can simply increment a counter, read a couple of bytes from the EEPROM at an address that corresponds with that counter value, and apply those bytes to various timers to turn the LEDs on/off to produce the required PWM, patterns etc.

I cant immediately think of any other reason to include something like that in something so cheap.

That also means you can use any manner of bargain basement microcontroller with minimal features, even if you have to bit bang some SPI or I2C to read the EEPROM.

If you have the tools, start with a dump of the EEPROM and see what it contains.

[james_s]

My guess is it's a very cheap microcontroller with an external EEPROM to hold the patterns. The hardware itself sounds pretty trivial, probably not much to reverse engineer. All the "magic" is going to be in the firmware but I doubt there's anything spectacular going on there either. Probably one of those cases where they found the cheapest possible way to build a whole bunch of these things.