| Author |
Message |
wanbong
Joined: 23 Sep 2008
Posts: 10
|
 06 Oct 2008 6:48 IR controller |
|
|
|
I'm working on a project using IR Led and IR detector to control a relay.
I created a circuit using 555 timer to create 38Khz square wave so that my IR Led can transmit at 38Khz.
Can anyone explain to me what kind of signal that will be output from the IR detector? As I saw from the oscilloscope my IR detector receive a wave form that look like
-|---|---|---|---|---|
the ' | ' appear when my IR Led waveform has an edge.
If this is correct I don't know how to control a relay from this signal output.
|
|
| Back to top |
|
 |
pranam77
Joined: 22 Apr 2008
Posts: 115
Helped: 8
Location: The heaven
|
| 06 Oct 2008 7:11 Re: IR controller |
|
|
|
| May i ask for what are you aiming to control through the relay? If you are planning to design an automatic tap or a hand dryer, i can send you a complete working PCB including sensors, and relay. If intrested, please PM me. Good luck.
|
|
| Back to top |
|
|
wanbong
Joined: 23 Sep 2008
Posts: 10
|
| 06 Oct 2008 7:39 IR controller |
|
|
|
| at first I'm intend to test the circuit by turning on off a Led light. when I switch on the IR transmitter the Led will switch on -> off or off -> on
|
|
| Back to top |
|
|
penoy_balut
Joined: 08 Sep 2007
Posts: 129
Helped: 16
|
| 06 Oct 2008 8:04 IR controller |
|
|
|
| that edge comes out when 38khz is received, to transmit data you have to modulate carrier frequency with data you want to send, on the receiver side it's the modulation that is decoded as data, one popular protocol is RC5, many sites discuss about it and quite easy to understand
|
|
| Back to top |
|
|
wanbong
Joined: 23 Sep 2008
Posts: 10
|
| 06 Oct 2008 8:13 IR controller |
|
|
|
| I kind of understand about the RC5, the problem is that I don't know how to read that edge, for example if I use an PIC16f877 I don't know how to make the PIC understand that egde. I saw some sites they let the output from IR detector go through op amp and control a relay, but I don't understand how can it work
|
|
| Back to top |
|
|
penoy_balut
Joined: 08 Sep 2007
Posts: 129
Helped: 16
|
| 06 Oct 2008 9:49 IR controller |
|
|
|
if you only need to switch relay on or off then an IR diode --> op amp --> flip flop (with delay) can do the job, whenever IR signal is received op amp will raise the voltage enough to trigger flop flop
try searching the net you can find schematics of this circuit
|
|
| Back to top |
|
|
wanbong
Joined: 23 Sep 2008
Posts: 10
|
| 14 Oct 2008 19:30 IR controller |
|
|
|
thanks for all ur reply I finish my IR remote control 
FYI, I use a 555 circuit to generate a 38kHz and NAND it with a PIC that send out serial data.
on the receiver side, I use a TSOP2238 (38kHz) IR detector, the output go through a inverter and go to a PIC. I think this way is easier than using RC5 method
|
|
| Back to top |
|
|
penoy_balut
Joined: 08 Sep 2007
Posts: 129
Helped: 16
|
|
| Back to top |
|
|
