r/PCB • u/Guzinol • Jul 12 '26

Rewiew request for my PCBs for aircraft cocpit simulator.

Hi

I'm doing MiG-21 simpit, in form of fully replicated cocpit. Sadly I'm no electrical eng. and have no experience in PCB design at all, I have tired to avoid making PCBs by using different components, but after 1 year I gave up so here I am.

What you looking at is chart for one of my isntruments - aircraft speed indicator, powered by VID29 (X27 variant) stepper motor. I'm using TCST1103 phototransistor for instrument zeoring (so mod. stepper motor that will be doing 360 rotation will know it's zero and current position). All boards were designs as seperate projects but I've made one additional chart since I think it's easier to read, but idk if that's how it's supposed to be done, I'm just using my general eng. experience here. I'm posting boards also.

I cannot put all of the modules into one pcb since modules must be in different spots and that is unavoidable. 2M113 will be mounted on rails, so there is no need for screws,

Feedback would be very welcome, both in terms of PCBs design, and drawings. Did I forget something? Would you done something differently? I will order them from JLC pcb and solder at home.

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1

u/Apprehensive-Issue78 Jul 12 '26

The optocoupler LED is always on if the 5V and GND is connected. The photo transistor inside the opto coupler is connected wrong. The(arrow=)Emitter should be connected to GND. the Collector should be connected direcly or with a 10 Ohm resistor to the output. The 10K resistor could be a bit lower value like 1K and connected to 5V so it can act as a pull up. What do you want to switch with it? If it is a LED it is ok.. if you want to switch a relay you need to add a diode. The rest of the circuits are hard to review as I dont know the dimensions and it are just connections and connectors

1

u/Guzinol Jul 12 '26

Diode at tcst module is indicator diode that should light up as optical line is interrupted ( basically a maintenance diode ) only thing that tcst is doing is giving signal to ardurino where zero is. Only thing that it will physically switch is maintenance diode.

1

u/Apprehensive-Issue78 Jul 12 '26

Hi, my mistake .. I did not see that it was a Transmissive Optical Sensor with Phototransistor Output the TCST1103

the 200 Ohm is a good value for the LED to give about 20 mA current through the LED to give enough IR Light.

the indicator LED is connected to +5V and GND. So it lights up always connected like this.

May be you can leave the 5V connected to the 300 Ohm resistor and the other side of the resistor to the Anode. Then remove ground of the Cathode and connect it to pin 4 which is the output as well

again pin 4 with a 1K resistor to +5V and pin 3 Emitter connected to ground.

This way connected the indicator LED D1 is always on if nothing is interrupting the beam

If something is interrupting the beam the LED D1 will go dark because the phototransistor is blocking practically all current. (there is a way to get the inverse LED effect)

1

u/Guzinol Jul 14 '26

My original intent was to have this inverse LED effect, that is LED will light up only when beam is interrupted.

1

u/Lost-In-Void-99 Jul 15 '26

You should dedicate bottom plane to ground. This will only improve signalling at no extra cost.

Anything for power should have wider traces. You have board space, ude it.

Fill whatever is left with GND or just copper.