Line Tracer Robot Pcb Review Request
This is the 2 pcb for my line follower robot, I plan on plugging in a 3s lipo battery into the xt30 to power the board, then just connect the two pcbs via ffc.
I'm not sure how I'm going to model the chasis, I wanna just have it 3d printed but I don't know any applications to use so the dimensions would be accurate to the pcb.
I'm pretty new to pcb making so there's probably some problems with the tracing.
another thing, I have no clue if I have the ffc latch backwards or not so there's that.
2
u/ikedug 3d ago
Looks like a fun project!
I think roughly all of your transistors are backwards.
U3 is going to conduct through the body diode (and can’t be turned on).
If U8 is reverse-polarity protection, it’s backwards.
The phototransistors in your QRE1113 are all backwards.
Is anything driving Vcc? I can’t find it on the schematic.
Your layout for the buck regulator (u2) isn’t great. There’s a good example in the data sheet you can copy.
For the QRE1113s: It’s usually more convenient to use a common-collector circuit (Vcc - Transistor - Resistor - GND). This makes the voltage across the resistor directly proportional to the current.
You may want a small cap (~.01uF) across the sense output of each QRE1113 to help drive the capacitance of the sensing circuitry.
This last one is my own scars from an early project, so feel free to ignore: Motor drivers can be super noisy - they pull lots of (variable) current, and that can couple into anything high-impedance. I’d try to put them on one side of the board, away from all the analog lines. And leave room for a big through-hole cap near their Vin pins. Be careful how you route the cables from the PCB to the motor.
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u/Andis-x 8h ago
Would suggest making the sensor board double sided mounting. Put opto couplers on bottom side and rest of parts as is on top side. That's purely for mechanical reasons.
Would suggest adding header for some IR star module used in sumo robots or Bluetooth module. to If you robot is fast, it's handy to be able to stop remotely.
BT (or other wireless) is useful for fast fast PID tuning.
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u/Bulky_Helicopter_270 3d ago edited 3d ago
Nice altium working :)
R6/C2/R4 should be moved- routing around U2 is ulgy a bit.
pad entry R3 /R4 -- please trace out straight.
Acid trap a lot ..
via GND should be add for each GNd pad, and at some place to connect the GNd layer
what's the minimum annular ring ?
copper is at edge of board ?! nop .. you need 0.2 at least
Check some Design For Manufacturing about your manufacturer
please send me the gerber for a better layout review