TSOP IR Receiver Help: Troubleshooting 4-5V Voltage Change

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Discussion Overview

The discussion revolves around troubleshooting issues with a TSOP 1738 IR receiver circuit designed to control a bulb using a household remote control. Participants explore the functionality of the TSOP receiver, voltage output expectations, and potential circuit modifications or alternatives.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes their circuit design using the TSOP 1738 and HRM 3800, noting that pressing the remote does not produce the expected voltage change.
  • Another participant suggests that additional circuitry may be necessary to achieve the desired voltage output from the TSOP.
  • Some participants request oscilloscope waveform pictures and schematics to better understand the issue.
  • One participant mentions that not all remote controls operate at 38 kHz and questions whether different remotes have been tested.
  • Another participant advises monitoring the TX signal from the remote's IR LED and checking the output from the TSOP to analyze the waveforms.
  • Concerns are raised about potential wiring issues with the TSOP, particularly regarding pin connections.
  • A participant indicates that the TSOP should output a DC transition when functioning correctly and questions whether the original poster has a faulty component if the output remains at 0 volts.

Areas of Agreement / Disagreement

Participants express various hypotheses about the cause of the issue, and there is no consensus on a single solution. Multiple competing views regarding the functionality of the TSOP and the remotes remain unresolved.

Contextual Notes

Participants have not yet confirmed the frequency of the remote signals with an oscilloscope, and there are uncertainties regarding the wiring and component functionality in the circuit.

Realhotshady
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well i m designing a simple circuit in which a bulb is turned on and off by a simple household remote control. Normal remote control gives IR of 38 khz so i m using TSOP 1738, there is also an alternative of HRM 3800. Well i m having a problem that neither of them r working. When i press the remote, it doesn't give any voltage change whereas i want at least 4-5volts. Can anyone help me with this by providing some circuit for TSOP which works properly or have any idea, please share it with me.
 
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From the datasheet, it looks like the thing gives out pulses corresponding to the IR pulse train from the zapper.

You may need additional circuitry to achieve what you require.
 
Realhotshady said:
well i m designing a simple circuit in which a bulb is turned on and off by a simple household remote control. Normal remote control gives IR of 38 khz so i m using TSOP 1738, there is also an alternative of HRM 3800. Well i m having a problem that neither of them r working. When i press the remote, it doesn't give any voltage change whereas i want at least 4-5volts. Can anyone help me with this by providing some circuit for TSOP which works properly or have any idea, please share it with me.

Post some oscilloscope waveform pictures and your schematic, so that we can be of help.
 
i've posted the complete circuit. Everything is working well except the TSOP part. the voltage doesn't change at all. what can i do now? is there any alternative or is there any way i can connect the TSOP? i m using a normal tv remote control. please help me out with this guys.
 

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The other thing that just crossed what passes for my mind is that all zappers are not 38kHz...

Have you tried it with a different make of zapper?
 
zeitghost said:
The other thing that just crossed what passes for my mind is that all zappers are not 38kHz...

Have you tried it with a different make of zapper?
zapper? u mean remote control? I've tried it with tv and vcd remotes but both didn't work at all. I've learned these remotes generally gives 38 khz. how can i test the frequency?
 
Realhotshady said:
i've posted the complete circuit. Everything is working well except the TSOP part. the voltage doesn't change at all. what can i do now? is there any alternative or is there any way i can connect the TSOP? i m using a normal tv remote control. please help me out with this guys.

When you trace the receive signal with an oscilloscope, what do you see? Monitor the TX signal at the remote control's IR LED to see what the 38kHz modulated TX signal looks like, and look for a similar signal at the output (collector) of T1 in the RX circuit. What do the waveforms look like?
 
Hmmm, The TSOP should strip the carrier and just put out the remote pulse train, if it works like similar devices. So the 100u cap should work as a peak detector and saturate T1 giving a single transition for any key press on the remote.
With a DC scope probe you should see a DC transition plus a bit of a triangle wave at the output of the TSOP.

Any chance you simply miss wired the tsop?
The pinout is different from the schematic layout as the center pin does not go to t1 base.
 
i've seen this datasheet and connected the pin as mentioned here. but still its not working. i'v not yet checked the frequency with oscilloscope which i'll do later when I've the access to oscilloscope. what will i do next?
 

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  • #10
Looking at the pdf and schematic, you should have 4-5 volts at the output of the TSOP with no remote input.
It should go to zero when triggered by the remote.
You can measure this with a DVM.

Your original post implies that the voltage you have is 0 always.
If this is so then you have a bad component in the circuit.
 
Last edited:

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