Hi Rongzhong,
Nybble is very awesome!
At the first calibration, after I sending ‘d’, it could sit well, I thought it’s OK, and had not yet tested others actions, I took off batteries and took one night rest, then occurred as I had described.
In fact, when I received the Nybble package, I was exciting very much. Then I assembled it quickly and locked all screws, wow, that really is awesome. At that moment, I remembered, I tried to put on the power, it had been occurred very whisper “pu-pu” and very a little smoking, I put off power immediately and found power reversed (BAD&TERRIBLE to myself). Then I read and checked the document ”Assembling Instructions for Nybble”, I found I made mistakes almost as reminded on the document,(:{} then I tried to do the first calibration immediately, it done as I had described above. Wow, I had been so exciting and rough mind to make mistakes.
Thanking for your replies and prompts in details, I will take acre of Nybble more carefully. TKS a lot again.(all devices are OK, I think I ruined or mess up the power supplied system,but it could work although abnormal. Oh, watch out 9V Alkaline battery measured about 4000mA it seems too strong ,even connected with HC-05)