Smart BLDC Commutator - V1 Fixes

This is V1 of the smart BLDC commutator. The final version is expected to be V3.

Changes from the version to the final version (i.e. things wrong with this version):
  • Changed N- and P-channel MOSFET gate driving strategy.
  • Changed silkscreen from 4081D (AND gate) to 4011B (NAND gate, pin compatible).
  • Made motor phase connection points to accept 3.5mm female bullet connectors (battery connections already this size).  
  • Added physical RESET button.
  • Changed hall sensor header to 2x3 position.

To get the board working you need to leave off three of the itty bitty MOSFETs and put a jumper across two of the pads (see image below). This will get it working, but you will be limited to operating at 5v on the uC side and 5-18v on the motor side.

I suggest leaving the AND gate in place since the NAND gate will require you to switch the PWM polarity off of the Arduino default. However, the high side MOSFETs will be in (conducting) when the uC pins are low, but the low side MOSFETs will be on when the uC pins are high. If you do change to the NAND gate all the MOSFETs will be on when the uC pins are low.

You will also need an ISP programmer to upload the code. I would highly recommend buying a dedicated programmer(I like this one), but a spare Arduino can be made to work in a pinch. Also, since this board uses a combination ISP/control pin header, you will need to replace one end of the ISP cable with a narrower profile connector. I used this one from Digi-key. A little pricey, but you only need one and it's easy enough to put together.

Firmware is hosted on GitHub.
Bill of materials and design files will be added to this page soon.

No comments:

Post a Comment