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Questions tagged [opto-isolator]

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4answers
77 views

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 ...
1
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1answer
270 views

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 ...
1
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3answers
317 views

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. =...
2
votes
1answer
160 views

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 ...
0
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1answer
2k views

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 ...
1
vote
1answer
394 views

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 ...
0
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2answers
165 views

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 ...
1
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3answers
934 views

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: http://www.datasheet4u.com/datasheet/H/1/1/H11L1_MotorolaInc.pdf.html)) I use the test circuit: simulate this ...