Troubles on power supplied

yeah I'm in Taiwan, good day to me, good night to you. Next shipping, I'II get new perk. Thx. I have to work~

Hi，

Thanks for responding quickly and honest with your mistake. I should have included a reverse-connection prevention circuit, but NyBoard was already too crowded, and the protection circuit would limit the current. I will find better solutions in future versions.

Maybe I should break one myself and try to repair, then provide you tips on repairing it. :P

There's another customer who broke it and is trying to fix it. Maybe he can post some tips here.

Are you in Taiwan? It's too costly to ship from the US. Maybe it's cheaper to ship from mainland China? I could ask the factory to send you a new NyBoard with discounts. You can email info@petoi.com to discuss next steps.

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)

Hi,

I'll try to analyse based on your observations and following up answers.

1. In process of calibrating that I could not make it well, when I restarted Nybble, Nybble could not work at all.

- Did Nybble ever work before? Did you connect the battery reversely to the power terminal? Have you noticed any sound, smoke or smell the moment when Nybble stopped working?

2. I try alkaline batteries (about 3-4V ) still could not start Nybble.

- Alkaline batteries won't work with Nybble.

3. I checked and connected with FIDI to the Nybble V0-1, Nybble could start again,but with handicapped servos’ actions. And It could upload any sketches well and run it.

- That means the logic chip is good and the blue LED eye should lit up. If the yellow LED eye (servos' power) doesn't lit or keeps flashing, the servos won't work properly for sure.

4. So I used “9V” battery(measured about 7.4V) instead of Li-ion batteries, It could start Nybble but still with handicapped servos’ actions, then I measured “9V” battery worked electronic current was about 250-260mA (not enough to drive all servos), at the same time, the 14500 lithium ion batteries shown more 8A? above(one probe of electric meter was very hot).

- Nybble should draw around 3A (+/-0.5A) during regular motion. The multimeter's probe can be hot because it's carrying large current through certain contact resistance.

5. I found Nybble V0-1 was wield that 14500 lithium ion batteries could not supply any power to the V0 board, then I measured at the terminals(shown as “gnd”,”battery” on the board of V0-1, linked from battery set), it shown about 0.19V, batteries still were about 8V, the battery set and wires is normal.

- This is strange. If you keep it connected for some time, will any component on the board become hot?

6. In V0_1 broad electric current layout, how many worked electronic current could drive well all servos?

- The step down chip (U2) for servos is rated at 5A. I've observed stable output around 4A with all 16 servos running.

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Here's my thoughts:

The logic circuit is good because you can upload and run sketches. By connecting FTDI, you are powering the logic circuit through USB. It's uncertain whether the powering chip for logic circuit is good. However, later you can power the board with 9V battery and the chip still works. So the powering chip for logic circuit should also be good.

The biggest problem is that the terminal measures only 0.19V when you connect 14500. If it works with "9V" battery, then it could be the problem of the 14500 batteries. Not necessarily to be its quality issue. It may just have a too sensitive over-current protection chip that auto shut off. Do you mean the battery claims 8A discharging current on its wrapping? What about its claimed capacity in mAh?

I also need you to do the following test:

Without connecting servos and FTDI, does the board power up normally with batteries? If the chip can start with both LEDs lit up steady, the problem should be in the servo.

Without powering on, check all the servos by rotating them slowly. Compare the feeling of resistance between servos. Do you find any servo hard to rotate or even get stuck? If the servo gets stuck inside, it will behave as a pure resistor and will pull large current. That large current will take away voltage on the chips and affect other servos' performance. It may even trigger over-current protection of your battery, making it always low when connected to the terminal.

I remember I once had similar problem but fixed it pretty quickly. Please provide answers to my questions in bold fonts. If I still cannot find a solution, you can email to info@petoi.com with your ID for replacement board.

Sorry, I measured “9V” battery worked electronic current should be about 0.25-0.26A(250-260mA).