i am trying to copy an IR signal from a remote for a project. I noticed that the data i am recieving from my TSOP38238 is different from the what the remote is transmitting. To show my problem here is a picture of a Oscilloscope.

enter image description here

The blue line is probed from the output pin of the TSOP38238 while the yellow line is probed from the positive LED pin of the remote.

If you noticed the one that i underlined in red, it would seems that TSOP was not able to detect these 4 burst. This does not happen consistently sometimes it would miss 1,2, or 3 times and i am getting a very low chance it getting the correct signal perfectly.

In the picture the circuit used is fairly straight forward. Using an arduino as a power supply:

  • 5v -> TSOP Vcc

I had not connected the TSOP OUT pin to anything yet except for the oscilloscope probe. I have also calculated that the remote's burst is around 38 khz.

I will be doing this to a fair amount of buttons and it would be highly inefficient to keep repeating over and over until it gets it right. I also don't have 24/7 access to this oscilloscope to check.

So what should i do to reduce or completely remove these errors. What is causing it? Is the TSOP38238 just a bad reciever? Are there better IR Reciever module alternatives that are available?

Thank you.

  • \$\begingroup\$ For starters, did you compare that this receiver is suitable for the protocol being transmitted? Datasheet does say that this receiver is not suitable for short bursts. Do you have the suggester filter on power supply? I don't recognize the protocol as it has the gap and so many bits, although it starts like NEC protocol. Zooming in to the signal will help you measure if the timings are suitable for this IR receiver. \$\endgroup\$
    – Justme
    Jul 30, 2019 at 9:30
  • \$\begingroup\$ Very good selector guide with background information: ww1.microchip.com/downloads/en/DeviceDoc/… \$\endgroup\$ Jul 30, 2019 at 9:51
  • \$\begingroup\$ Are you sure that it is 38 kHz? Why aren't you using the newer 38438? \$\endgroup\$
    – Mattman944
    Jul 30, 2019 at 13:04
  • \$\begingroup\$ @Justme I did not put the suggested filter yet, the data sheet did say that it is insensitive to noise and voltage ripple. Yes, i have noticed also that the protocol starts like NEC up until that big break in the middle, That is what the arduino library is saying (when i first attempted to copy it). Can you elaborate what should i look for when you said zooming in will let me see if the timing is suitable? what value in the datasheet am i trying to look for? \$\endgroup\$
    – Jake quin
    Jul 30, 2019 at 15:47
  • \$\begingroup\$ @PeterSmith Thank you for suggesting this, unfortunately i do not live in the us to easily order this components, but i will keep it as a reference for a last resort . \$\endgroup\$
    – Jake quin
    Jul 30, 2019 at 15:51

1 Answer 1


I gave up on the part that i used and instead used a TSOP4838 it worked great, it doesnt even need the complimentary circuits. I could not assess what is wrong with the TSOP38238 because i do not have an extra part to test if my piece was defective


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