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Q: How much does it cost?

A: It depends on what your target is and which options you choose. A fully assembled controller with all parts and options costs currently around 100$. (This issue will be addressed in the future to make Open-BLDC options that are more affordable) With the new Strip controller we hope to have an entry level hardware that can retail for as low as $20.

Q: Where can I buy it?

A: At the PCB manufacturer and electronic parts supplier of your choice. There is no company producing Open-BLDC, so you have to order the PCB's and parts yourself and assemble the controllers. You can also get together with other people and make an omnibus order. For ask on the mailinglist! (Update 04 Sep 2012: With the Strip controller we are considering doing a Kickstarter campaign to make them available, there will be a news update on the front page when that happens. We are not planning to produce the earlier much more expensive versions of Open-BLDC at the moment.)

Q: Why is it so big?

A: Open-BLDC has as opposed to other motor controller designs many additional sensors to make Vector control possible. The goal is also to make the best possible controller and not the smallest or cheapest. This boils down to the following additional parts:

  • 4 Hall based current sensors
  • 3 Halfbridge drivers
  • 1 Chargepump for 12V
  • ...

Additionally to that we decided to use D2PAK mosfets. These packages are twice the size of DPAK or three times the size of SO8 packages. They have much better heat dissipation properties which leads to lower losses and higher supported currents. Without heatsink use.

(Update 04 Sep 2012: Strip is much smaller providing less functionality and power but making it ideal for small multicopters.)

Q: Why do we need 3V3 power rail?

A: STM32 is a 3V3 microcontroller

Q: Why do we need 5V power rail?

There are no integrated Hal sensor based current sensors that would run on 3V3 (If you find any let us know!)