Questions tagged [opto-isolator]

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Resistor - Correct value for optocoupler, but dont have that size

I am making a shutter for my camera using a Arduino and an optocoupler. I understand most of most parts, but unsure about the resistor because I don't have the correct size. 5V will be coming from the ...
Stephen Mottershead's user avatar
1 vote
2 answers

Read encoder output by using an optocoupler

I have a 512 pulses encoder with four wires: +5V, ChannelA, ChannelB, GND and I'm using it as feedback for my motor position (max 80 RPM) on Arduino UNO. Everything works fine, but I need also to ...
Marcus Barnet's user avatar
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How to debug MIDI input?

I'm trying to receive MIDI messages on a Leonardo. To do that I used the circuit in the diagram below (only the top half for receiving). The only thing I did differently was using an 1N4148 diode ...
flawr's user avatar
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4 answers

Detect if laptop is on or not?

How would I safely connect an Arduino so that it can detect if a laptop is on or off? The Arduino would be powered separately by a normal USB charger, since it needs to be turned on even when the ...
Magnus's user avatar
  • 157
1 vote
2 answers

Normally-Open opto-coupler board

I'm looking for a Normally-Open optocoupler board for arduino. I need to control power of a device (DC 12v, 500mA). I tried to use TLP281 board, which works, except that it inverts the output: device ...
Igor Liferenko's user avatar
2 votes
4 answers

How do I properly receive MIDI with Arduino, with 6n138?

UPDATE : I still can't receive MIDI as of 2019/07/01. Here goes so far : I'm trying to follow this schematics from instructables, using 6N138. To make it easier, I'm going to copy his schematics. =...
Rinaldo Jonathan's user avatar
1 vote
1 answer

How to prevent optocoupler to activate when resetting the arduino? [closed]

From various example on how to use optocouplers ( eg 4N25) I gathered that they work in inverted way meaning that for the optocoupler to output a signal, the input LED must be OFF. This is very easy ...
CodeFlakes's user avatar
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Connect optocoupler 4N35 to Arduino Uno to control LED light strips

I want to use an Arduino Uno to control the LED light strips, based on the input signal from a robot controller. The robot controller sends a digital signal with "HIGH" of 24 V and "LOW" of 0 V. I ...
triata's user avatar
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1 vote
1 answer

ATtiny85 MIDI IN with less than 3V -can it be done? [closed]

I've been trying to add a MIDI INput to an ATtiny-based synthesizer, powered by a CR2032 battery (3v) and running softwareSerial. Currently I'm using an H11L1 optocoupler, which works fine at 5v, but ...
jose's user avatar
  • 21
1 vote
2 answers

Arduino and Optoisolators

I am looking for an efficient (and safe) way to use the Arduino to switch a higher voltage device off and on. The first option would be a relay, but they are fairly bulky. I was wondering if I should ...
DaveLister's user avatar
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3 answers

H11L1 opto isolator does not pass signal to Arduino (correctly)

I have made a very basic test circuit for the opto coupler H11L1 ('similar'datasheet: I use the test circuit: simulate this ...
Michel Keijzers's user avatar