How to interface IR to uC?

[ltg]

mcp2120 osram

Hi,

I use Op-amp to amplifier signal from phototransitor. I don't know which is best to interface output from Op-amp to a AD I/O or a digital I/O.
I use IR led to send out binary pattern. Would some of you please give me some tips? Thanks in advance!

Best Regards,
ltg

 

[waterman]

I guess you want to make an remote control.
If so, you could use an IR receiver from makers
(e.g., Sharp) to receive and get an envelop.

Then you could use a counter to count periods
to get remote control code.

 

[mr_ghz]

Hi ltg

as waterman wrote, I think it's best if you use a complete IR receiver.
Normally a transmitted binary datastream is modulated with a carrier-
frequency (e.g. 40kHz). If this signal is 'seen' it would be a logic '1', if
not it's a logic '0'.
You can also build your own receiver (with photodiode and OP's). In this
case you must implement an (high gain) amplifier, a bandpass and after
this a comperator. The output of the comperator drives directly a digital
input of your uC. Perhaps (it depends on the protocol) you can use the
UART-input of your uC.

Greets

 

[Analyzer]

Hi,

Maybe you interest at instant hybrid ir-ic's like minisir (www.novalog.com) It is a very talented ic and you can easily connect it to your mcu.

Analyzer.

 

[psubiaco]

Vishay distribute TSOP1838 which is a complete IR receiver with high sensibility... the IR signal must be modulated at 38KHz, as TV remote controllers do.
In alternative you can use a BJT which amplify the phototransistor signal, taking care to use DC decoupling to avoid sun noise.
Regards. Paolo

 

[Ace-X]

Here there is a very good intro to IR:
**broken link removed**

and overview+pinout of most famous opto-devices:
**broken link removed**

Ace-X.

 

[ltg]

Hi,

Thanks a lot for your tips. I'm using SFH420 and SFH320 (OSRAM). But they don't work in dark. I don't why, because IR should be independent which evironment you are?! Do I have wrong amplifier? I use two resistants and an Op-amp.
Best Regards
ltg

 

[luben111]

Microchip offers complete IR solution - their chip supports all layers of IR protocol MCP2120 adn MCP2150

**broken link removed**

**broken link removed**

And you can read about their family of IR devices
https://www.microchip.com/download/lit/pline/analog/interfce/infrared/21627c.pdf

Regards
Luben

 

[velislav]

RC-5 to RS232 converter

A very good explanation of the RC-5 coding and an RC-5 to RS232 converter is described here:

hxxp://www.telesys.ru/projects/proj036/index.shtml
(in russian)