1
\$\begingroup\$

I have a KY-005 infrared transmitter connected to my Arduino Uno. But currently I can't get it to work. On this website it says that you must connect the led directly to a digital pin on the Arduino, which I have not done (I connected it in series with a 220 ohm resistor. Because i don’t Thrust the led can handle it)

Is it correct that you can/must connect it directly?

Update: i hooked up the led directly to the arduino pin 3 (not +5V) and that did. it now works

\$\endgroup\$
5
  • \$\begingroup\$ The module is a 5 volt module and arduino is a 5 volt device. So there is no need for a resistor! \$\endgroup\$
    – MatsK
    Commented Sep 8, 2019 at 14:52
  • 1
    \$\begingroup\$ The KY-005 isn't just an LED. It is a driver module and LED. \$\endgroup\$
    – JRE
    Commented Sep 8, 2019 at 15:14
  • 1
    \$\begingroup\$ The information on this parts website is self contradictory, as it claims to be just an LED but then instructs that three connections be made. Best to buy things with actual specifications instead of mysteries. \$\endgroup\$
    – Chris Stratton
    Commented Sep 8, 2019 at 22:15
  • \$\begingroup\$ I now see that i should have bought something else \$\endgroup\$
    – jk_games
    Commented Sep 9, 2019 at 15:34
  • \$\begingroup\$ That product page makes no sense at all. It says "just an LED", but it shows using three wires to hook it up. It says "just an LED" (implying Vf=~1.5V; the resistor pad in the image is unpopulated), but suggests hooking it up straight to a 5V arduino. It also says the LED is "emitting at 38kHz". So many contradictions. Just... Just no. \$\endgroup\$
    – marcelm
    Commented Sep 9, 2019 at 16:20

2 Answers 2

Reset to default
3
\$\begingroup\$

According to your link "The KY-005 Infrared Transmitter Module consists of just a 5mm IR LED.". This is confirmed in this YouTube video (image below is from the video).

enter image description here

Infrared is not visible to the human eye, but you can check to see if it is emitting light using the camera in a cell phone or laptop computer.

Connecting it directly to the Arduino I/O pin produces the most light, but relies on the internal resistance of the port to limit current. This is safe provided no other pins are driving heavy loads (ATmega328 absolute maximum current for all MCU pins combined is 200mA). It should still work with a resistor, but with shorter range. With 220Ω it should draw about 15mA, which is around half the current it draws with a direct connection.

Note: do not connect the 'signal' input directly to +5V, as it will burn out the LED!

\$\endgroup\$
3
  • \$\begingroup\$ I currently can’t test it but, when i can i will test the circuit with the led directory connect to the pin of my Arduino if that doesn’t work i Will see if my laptop can capture Ir light because i know my phone can’t (i tested it before with a normal remote) \$\endgroup\$
    – jk_games
    Commented Sep 9, 2019 at 15:31
  • \$\begingroup\$ "This is safe provided no other pins are driving heavy loads (ATmega328 absolute maximum current for all MCU pins combined is 200mA)." - It isn't safe; atmega328P absolute maximum current for a single pin is 40mA. To stay within the MCUs operational limits, you need to obey both the 40mA/pin limit and the 200mA total limit. \$\endgroup\$
    – marcelm
    Commented Sep 9, 2019 at 16:22
  • \$\begingroup\$ i tested it and my pc camera was able to pick up the Ir signal but it was very faint. however when i directly hooked up the led it was much brighter and now it works!! \$\endgroup\$
    – jk_games
    Commented Sep 9, 2019 at 16:35
-1
\$\begingroup\$

The operating voltage of the KY-005 is 5V, according to the web site, and it can be driven directly from an Arduino output. You should be able to detect it with the series resistor, perhaps you have a software problem.

\$\endgroup\$
3
  • \$\begingroup\$ do you know any way to test if my program is working or not? \$\endgroup\$
    – jk_games
    Commented Sep 8, 2019 at 16:50
  • \$\begingroup\$ Put a 'scope on the detector output. \$\endgroup\$
    – Leon Heller
    Commented Sep 9, 2019 at 6:14
  • \$\begingroup\$ I don’t have a scope \$\endgroup\$
    – jk_games
    Commented Sep 9, 2019 at 15:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.