How to fix Roomba 500 series battery problem

My Roomba 520 has been out of service for more than six months. The wheels worked fine but the internal brushes didn't turn around anymore. I picked it apart and cleaned the internal gears and engine several times which made it work for a while but I finally gave in and bought a new engine.

Surprise, surprise, it refused to start even after charging it for more than one day. I always got this never ending loop:

It successfully undocked from its docking station but it just reset whenever it tried to start the brushes which led me to believe it was a low battery problem.

Mixing various instructions I found on the internet, I ended up with this procedure which seems to fix the problem:

1. Connect the Roomba and charge it completely (until the light turns  green)
2. Disconnect the Roomba from the charger (the light turns off)
3. Turn on the Roomba by pressing the Start button once (the light turns green)
4. Press and hold down the Dock and Spot buttons for 15 seconds to reset the Roomba (the Roomba turns off)
5. Release the Dock and Spot buttons (the Romba plays the 5 tone startup sound)
6. Go back to step 1

I have repeated the procedure 5 times so far and the run time keeps increasing. 

The Nabaztag is dead, long live the Nabaztag

My Nabaztag has been collecting dust on my desk since the online service powering it died this summer.

The first meeting of GTUG Milano was the perfect excuse to have some fun and use the Nabaztag for something useful. Using this Nabaztag disassembly video it didn't take long to pick it apart and figure out which wires controlled what.

Thomas took care of all the electronics work and I added some lines of code to the Android ADK demo code to create a proof of concept Android ADK powered rabbit.

  

Take it for what it is; a proof of concept that just controls the two ears, 3 multi color LEDs and does some text to speech. It does not do any of the useful things that the Nabaztag did like reading mails, rss feeds, showing weather information etc.

It could though, as all of it is easy to implement on Android. Which is why it's time to make it do something useful :-)

I've decided to replace the Android ADK Demo Shield with a Arduino Mega ADK which is smaller an "only" costs 59 euro. It will be the interface with the Nabaztag hardware and control the ears and LEDs initially. The rest of the work will be done by an Android device.

To be perfectly honest, I probably got a bit carried way when ordering the Arduino Mega ADK. I got some LEDs with the idea of organizing them in a grid to show basic symbols, but then I found the 32x16 LED matrix and couldn't resist it. The idea of replacing the 3 multi colored LEDs found in the Nabaztag with something that can display information was just too much to resist. I think it should fit in the almost empty Nabaztag shell but I may have to do some rabbit surgery if it doesn't.

Add the power of cellbots and we have a pretty powerful rabbit on our hands. Let's just hope it does not turn Evil...