I’m trying to replicate a certain motor driver that someone on Make Magazine made:
If you follow that link you can click on ‘7. Drill holes in the PCB’, there’s 3 pictures that you can look at…or, I posted them below.
If it’s relevant, a very brief background summary:
Ultimately, I plan on doing the same thing that he is - control 2 independent wheelchair motors with (2) 12V wheelchair batteries (in series), so at 24V…via Arduino of course.
Anyway, I’m pretty much stuck at the 2nd photo - the transistors. I don’t know which transistors go where and how they’re oriented. I think all the heatsinks for his transistors make it hard to tell.
His BoM called for the following transistors:
(12) N-Channel MOSFET 52A 60V - Digikey Part#FQP50N06L
(12) P-Channel MOSFET 47A 60V - Digikey Part#FQP47P06
(4) N-Channel MOSFET 60V 200mA - Digikey Part#2N7000FS
Photos from the Make Magazine article/tutorial:
My photos from my board that I’m making:
Note - since this is showing up so small, I also ‘attached’ it to this post.
I’ll break down my big/vague/general question into 5 individual, focused questions about populating this board:
Question #1 (reference ‘my’ photo #2) - Do I have the transistors in the correct orientation? (Note - I came up with the orientation that I have it in just by referencing his photos…I did not come up with what I did from the schematic)
In ‘my’ photo #1, I broke down the board into 8 rows to make things a little easier to reference. I just put 1 transistor in each row to show which way I think how the transistors in that row should be oriented. (Don’t worry, I didn’t solder those yet)
Question #2 (reference ‘my’ photo #2) - Of the big transistors, which ones go where? I’m trying to figure out the schematic, but just can’t decipher/translate it into hooking them all up onto the board. There’s (12) N-Channel (52A 60V) and (12) P-Channel (47A 60V), but have no idea where they all go. Do they alternate by row? Do they go in ‘quadrants’ (1 kind in Rows 1 and 2, the other kind in Rows 3 and 4, 1st kind in 5 and 6, etc.)?
Question #3 (reference ‘my’ photo #3) - Do I have these little transistors oriented correctly? Again, this is how I have them from referencing his photos. It’s kind of hard to tell for sure if I have all 4 correct.
(the blue circles will be part of my next question)
Question #4 (reference ‘my’ photo #3) - I think I drilled 4 total extra holes on the board (where the small transistors go). So not only am I not sure about the orientation (see previous question), but I’m not sure about the placement. If you look at ‘my’ photo #2, you can see that there are 4 holes there for the 4 different little transistors instead of 3. Sooo, in photo #3 I circled in blue the un-used holes that I have next to each little transistor. Basically I used the 3 holes that are closest to the ‘inside’ of the board for each small transistor. But, I don’t know if it’s the correct 3 holes for each of the 4 small transistor locations.
Question #5 (reference ‘my’ photo #5) - If you look at his photos #1 and #2, it looks like he’s got some (2 wires in each location) bare-metal ‘jumper’ wires near each small transistor. If you look at ‘my’ photo #5 I circled in blue the places where I believe they go. Am I correct about this? Is that just bare wire acting as jumpers?
I would be leaving a comment on his tutorial for all these questions, but he hasn’t responded in a long time now, and everywhere I look for him it looks like he’s MIA. So I’m turning to the Arduino community. I’m actually going to be controlling this motor driver board with an Arduino ultimately anyway.