I appreciated your hard work to decode the circuit. I have two Spybots and they are still working well, and I feel wrong to throw them away. Then (20 years ago) I collected many documents and software related to these bricks, however at these modern days finally I have to use the NQC and BricxCC via a serial port of my desktop.
Fascinating! I've been looking for something like this for a while, and was intending on disassembling one of my own (probably still will). Have you gotten much further since April? I've done a lot of work reverse engineering the IR communication and detection protocols the Spybots use and I've discovered some interesting things. The Spybots use the 3 flat/clear IR beacons and 2 IR detectors in order to "see" each other (& the remotes). I believe the feedback portion of the beacon circuit you found is to remove reflections of the Spybots own beacon from the detectors (so it won't "see" it's reflections). The dark blue IR transmitter is what is used by the Spybots to send messages back and forth (received by the detectors). However, it can also be reconfigured via programming to act as a serial UART and send essentially arbitrary IR codes. It can talk to the RCX and control other Spybots (or the Manta motors) this way. With the correct programming, you can also upload code to a Spybot using an RCX infrared tower instead of the light tube. See these links: pbrick.info/2013/10/controlling-a-spybotics-pbrick-using-an-rcx ofalcao.pt/blog/2017/decoding-old-lego-infrared-protocol I've managed to get a Spybot to detect an RCX as another Spybot, by having the RCX playback the Spybot beacon. Getting a Spybot to detect the *location* the RCX has proven a bit trickier, as the Spybots seem to be also transmitting a "verification" signal from their serial IR TX that is overlayed on top of the three beacons, and I've yet to decode it enough to reproduce properly. Also, according to this, the microcontroller is likely an Hitachi H8: www.avrfreaks.net/forum/ot-lego-spybots Cheers, and let me know how you're making out!
Thanks very useful ☺️. I've moved on to other things I hope to get back to Spybot's sometime. Using cells from discarded vapes is taking most of my time. I hope to use them in Spybots and other things when I've got them sorted.
