3.3v sensor on 5v output?

I have been looking for an answer for this for a few days now and keep getting information pertaining to the opposite. The sensors that I am trying to use. I know work with a 3.3v vcc.... The board that I am trying to swap them over to, has a 5v output. When I test with multimeter, the sensor shows 4.97 volts from vcc and to signal. When I trip the sensor there is no visible change. On the board that I know that it works on, it shows something like 1.8v to the vcc, and 3.3 to the signal. When I trip the sensor on that one, the 3.3v drops to 0 as I would expect that it should.I am assuming that the hint lies in the fact that the vcc and signal are close to being a multiple of each other... but I am far from understanding electrical. If anyone could let me know a way to get this working I would really appreciate it. Oh and I guess it would help to mention that the sensor is an optical sensor used as an end stop on a printer.

The board it is coming from is a Due based board, and the one it is going to is a Mega 2560 based board.... I dont think that matters though.

One last thing is I am not looking for a solution which involves going and buying some new sensors... I am only asking this because I am looking for a way to use the sensors that I already have. Thanks so much again for any info.

Is that your own photo ? Taken in 2014 ? Used here: https://trandi.wordpress.com/2014/12/11/optical-wheel-encoder-from-infrared-printer-sensor/ and you already had it working with 5V ?

If that is not your own photo, can you tell the brand and type of the sensor or module that you use.

Your "opto-fork" doesn't care if you use 1.5V, 3.3V or 5V - as long as it's more than 1.2V it will be happy.

What is inside the "forks" is an infrared LED and an infrared sensitive phototransistor. To use it you need two resistors, sized for your supply voltage.

// Per.

No it is not my photo, I just found the pic to hellp explain it. I have had it working but not on this new board. Zapro, can you please elaborate on the size resistors and how to hook them up? As far as a model number, all they say on the side of them is 423 on one side and SG on the other.

Here's a very good article explaining how to use the device: Connecting a photo interrupter/optoisolator to an Arduino | Martyn Currey

// Per.