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Unread 15-03-2016, 14:37
GreyingJay GreyingJay is offline
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AKA: Mr. Lam
FRC #2706 (Merge Robotics)
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Re: Standard Motor Driver Schematic for FRC

Quote:
Originally Posted by Jared View Post
I don't think too many teams have the resources/skills to make motor drivers for less than the cost of something like the Spark given only schematics.

Even though you might be able to buy all the components for real cheap on Digikey, you don't have a circuit board. Some weird parts like gate drivers might only come in surface mount packages sometimes. Even if you did find all the parts in through hole packages, you need to worry about all sorts of electrical interference issues - the FRC controllers don't have isolated logic and power, so you'd need to be clever with how you laid out your board to prevent transients from messing with the microcontroller.

Then, you'd have to figure out how to program the microcontroller. I have yet to find a through hole microcontroller that supports a direct USB connection, so you'd need to buy some sort of programming board or get really good a surface mount soldering.
The expected audience for this particular scenario seems very small: a team with a low budget that does not want, or cannot afford, to buy motor controllers, but can buy the discrete components, with the students having access to PCB manufacturing equipment, and who are (will become) skilled in circuit design, component layout, soldering, testing, etc.

If this describes your students, then a home-made motor controller might be an excellent off-season project to develop an intimate familiarity with how they work. I daresay that after the experience they will also gain an appreciation of how much work goes into a motor controller and how much value you get for the $40-60.

When I learned to do woodworking one of my first projects was an Adirondack chair. I found plans online, purchased pine boards, and started marking, measuring, cutting, shaping, sanding, routing, drilling, assembling, gluing, clamping, more sanding, staining, more sanding, etc. I probably spent $100+ in raw materials, and dozens of hours of my time. Then one day I walked into Costco and they had Adirondack chairs for $49 each...
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