InfraRed ramblings

[Demon]

Using this 940nm LED set on Amazon: https://www.amazon.ca/dp/B01HGIQ8NG

Can I have the transmitter LED on without any pulsing? (resistor values are temporary, did not do any calculations yet)



This circuit was inspired by this tutorial: https://www.instructables.com/Intro-to-IR-Circuits/

I just want to detect a hole in a disk; no communication.


Examples on google often use 38kHz or 56kHz, but their receiver has 3 pins; VDD, VSS and DAT. That leads to me to believe there's more going on in that receiver.

This guy has a really nice way to calculate the values:

[richard]

if there is any ambient light leakage a ir sensor like SEN-19018 would be better than a photo diode, with the bonus of making
led modulation unnecessary too.

if the distance between led and sensor is small [under 10mm] then you only need a small current through led 5 to 20 mA
would be heaps

[Demon]

There will be minimal light leakage. These will be on either side of a disk, as close as I can get them.

I plan on putting black heatshrink over the LEDs as close as I can to the rotating disk.

This will be used as a way to home a stepper (fuel gauge on a flight sim); I need to find 0 easily. I'm sure there as more precise techniques, but I'm looking for a simple low-cost solution that works.

I was planning on using these steppers: https://www.amazon.ca/dp/B0CPSLS944

[mark_s]

Search optical interrupter. These are used often for homing.

https://www.amazon.ca/s?k=optical+in...ref=nb_sb_noss

[Demon]

ARGH! That's what they're called. I knew these existed, I just didn't know their names.

[mark_s]

You can also use a hall effect IC and a small magnet. The hall effect ic's come in a 3 pin TO-92 package and are easy to interface to your micro.

For example

https://dronebotworkshop.com/stepper-motor-hall-effect/