Schematic and PCB Help

Looking for some help on my schematic and PCB.

I’m developing a device that heats and vibrates and is worn on the body, I’d like to keep the PCB as small as possible. I’ve laid out my schematic but I’m not sure if it is accurate.

Any help is appreciated!

HeatingPad.fzz (31.3 KB)

I think there are some «make that a lot of» problems with your circuit.

To start, i doubt that the microcontroller can supply enough power to directly run the heating and vibration elements. You will need some sort of switch (maybe a FET) to switch power for them on and off.

connecting the vibration and heating elements through the pressure sensors is probably not going to work either. More likely, you need to setup to have the µC read the sensors, then send signals to the elements (through switches/amplifiers/FETs) based on the values.

Power is not wired up right either. The schematic shows “VDD” conecting to “D-” on the USB connector, VSS driving one of the LEDs; the on/off button connecting the positive side of the battery to ground; VCC for the temp sensor connecting to SERIN.

I do not know the um-fpu microcontroller, and am not going to lookup data sheets for this quick check, so not going to make a guess at how it should be wired up. It looks though like it does not have enough I/O channels to do what you want.

You have a lot of wires to the usb-C connector, with no information about what that is to be used for.

To be able to estimate how ‘small’ the pcb could be, you first need to finish the wiring. There are a lot of ratsnest lines left on PCB where no connection exists yet. This is shown (in part) by the message at the bottom that says 12 of 27 nets rounted - 21 connections still to be routed. The existing traces are not valid either. Several are shorting out to other traces and pins. On PCB view, run “Design Rules Check” on the “routing menu”. All of the resulting “red” are problems it detects.

If you are really trying to make this smaller, use SMD components instead of THT (through-hole).

At this point I would say the PCB content is useless. Start with a much larger board, and get a layout that you can actually complete the wiring on. Get the traces to where it shows “Routing Complete”, and where DRC does not report any errors. ONLY then, start moving pieces closer together, while adjusting the traces, to shrink the board.

Before creating a PCB, you need to verify the circuit actually works. That is one of the things that breadboard is for. Shrinking the PCB size is useless if it does not work to start with.