draft for donut board (aka "pad" or "matrix" board)

zimin · ‎2025-11-28

Title edited to clarify "donut board"

I would like to connect the LM324(below) to the STM32F103C8T6 on a donut board, purpose to read four IR receivers. VR with highlight T shape is preset 103. IR1, IR2, IR3, IR4, 5V and ground will connect to a 6 pin header, connect to another donut board which contains only 4 groups of IR transmitters and receivers.

My task is without jumper wires connect them together but I can’t connect it due to the preset 103 make the circuit too messy. Can anyone help me please.:folded_hands:

Andrew Neil · ‎2025-11-28

You're not going to be able to do it without some crossing wires.

Even if you created a custom PCB with just one copper layer, you'd have to put in some jumpers.

You need to start by drawing a proper schematic of you full circuit.

From that, you can try to lay out your components & connections on the board so as to minimise crossing wires.

You can achieve crossing wires without having to use insulated wire by going up to the top layer, then back down again - just like you run wires under the resistors.

Example:

Source: https://effectpedalkits.com/how-to-read-a-veroboard/ - which is actually using Veroboard ("stripboard"), but the principle is the same.

@zimin wrote:
My lecturer don’t want the circuit is messy so don’t allow to use jumper wires I think.

What do you mean, "I think" ?

Don't guess - if you're not sure, go and ask!

I think my example shows that using wires doesn't have to be messy ... ?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.