Hello, I Just finished to build a modified Elektor Wheelie. My mechanics is slightly different from Elektor kit, as I use a chain, but motors are the same.
The problem I am facing is: when I start wheelie (pushing the presence button) for some fraction of second the algorythm seem to work (motors move slowly, sometimes in the same direction sometimes in opposite), but then both motors start to accelerate until 17V and they never stop. I made these trials with wheelie standing still on a tripod. I tried to ride my wheelie, too, but it runned away and I falled off. I think this is NOT supposed to happen !
In my project I made a little change on Elektor hardware: I wasn't able to find the IDG-300 gyroscope, so I redesigned the gyroboard with an ST LPR550AL. The sensitivity is the same, ±500 °/s, the Zero-rate level is different (1.23 V for LPR550, 1.5 V for IDG), but I don't think ths should be a problem, as firmware makes a "zero point" at startup. I made my tests on this tripod, and the outputs of acceleremeter sticks to 1.5 V, while outputs of gyroscope sticks to 1.23 V (perhaps some little oscillation due to motor vibration, but the problem remains if I disconnect motors).
I programmed the ATMega32 with "official Elektor firmware".
Do you have any idea that could help me ? Thank you very much.