TSOP 1738 38KHz IR Receiver

[farhad ali]

I've been looking all over the Internet for what I thought would be an easy thing to find instructions on. Unfortunatley, anything that comes close either complicates the matter with extra features or assumes I know a lot more about electronics than I do...

I need to build a very simple circuit: When it detects an infrared signal, it lights up an LED which stays lit for as long as the IR signal is active.

The problem is that it needs to not drain it's battery much when it is subjected to ambient light, including some sunlight through stained-glass windows. (This is going to go into a church and will serve as a stand-up signal for the choir.)

Everything I have found online is either too sensitive to ambient light, or has decoding chips for complex signals. I just need something very simple.

If I had just a components list of stuff that I could get at Radio Shack or similar places, I'm sure I could easily figure out how it works and build it.

Does anybody have any suggestions on where I could start? (I used to think I was a little proficient with electronics. In researching this, and seeing the "simple" circuits offered up on the Internet, I've come to realize that I'm much more clueless than I ever imagined.) :(

Any pointers would be greatly appreciated.

Thanks,
Farhad

 

[aresnick]

So I don't think Radio Shack sells these, but you can purchase photodiodes or phototransistors with coatings that select for certain wavelengths. With that, a battery, and a resistor, you should be able to hook up an LED between them, and when IR hits the photo{diode,transistor}, current flows and lights up the LED.

Unfortunately, I can't post links, yet, but if you Google (ir detector circuit "junk box") the first link should give you an idea. . .

Hope this helps,
a.

 

[oswaler]

Dear Farhad,

Thank you for reaching out for help with your project. It sounds like you have a clear idea of what you want to accomplish, but are having trouble finding the right resources to help you achieve it. I can understand your frustration with the complicated circuits and lack of simple instructions available online.

First, let me introduce you to the TSOP 1738 38KHz IR Receiver. This is a common component used in infrared remote control systems. It is designed to receive and decode signals from a remote control and then send those signals to a microcontroller or other electronic device. However, in your case, you do not need the decoding capabilities of this receiver. You simply need it to detect an IR signal and trigger an LED to light up.

To achieve this, you will need the following components: a TSOP 1738 38KHz IR Receiver, an LED, a resistor (220 ohms should work), a transistor (2N3904 or similar), and a power source (such as a 9V battery). You should be able to find these components at your local electronics store or online.

Here is a simple circuit diagram that should work for your project:

[TSOP 1738] --- [Transistor] --- [LED]
| |
| |
[Resistor] [Power source]

The TSOP 1738 should be connected to the base of the transistor and the LED should be connected to the collector. The resistor should be connected between the base and the power source. You may need to experiment with the exact values of the resistor and transistor to get the sensitivity and response time you desire. You can also add a switch to turn the circuit on and off as needed.

The key to reducing sensitivity to ambient light is to use a resistor and transistor that will only allow the LED to turn on when a strong IR signal is received. This will prevent the LED from lighting up in response to other sources of light. You can also experiment with different types of plastic or covers to further reduce sensitivity to ambient light.

I hope this helps you get started on your project. If you have any further questions or need more guidance, please do not hesitate to reach out for help. Good luck!

Sincerely,