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How To Make Switch Using IR Paired LEDs? And How To Shunt LED Positions?

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lwinicki

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Hi all,

I am currently working with an advertisement kit by Velleman (found **broken link removed**), and I am almost finished!

I already soldered all parts, except that I have to shunt unused LED positions by means of jump wire. What exactly does that mean? I have the wire, but I'm not sure how I'm supposed to solder in into place.

Also, I want the sign to be able to turn on by the use of a pair of LEDs, one IR emitter and the other a phototransistor detector (found here).
In reality, I don't know how to wire any of it. I know that the emitter will have to have a separate power source, but how much voltage should I use? And what about using a resistor?
The other major thing is that I don't know how to wire the phototransistor detector to the sign, that way the sign only turns on when the detector receives the IR from the emitter.

Can anyone help me out? I will greatly appreciate it. :)

Thanks!
 
Cut a small length of wire, bend it in half and solder it where the LED would go. That's a jumper.

You'll need more than just a lonely phototransistor, even if you make it work with the proper additional components any ambient light source will wreak havoc on your display. I'll try to find something more suitable to your needs.
 
jimlovell777, thanks so much!
I knew I was on the right track with the jumpers :D

And about the one phototransistor, will it work better if I tested it in a dark room?
 
You can test in a dark room but it won't save you from trouble down the road. A modulated ir signal or better a coded ir signal is your best bet. Does the unit have an on/off switch? Is the switch momentary or slide?
 
The unit doesn't have an on/off switch. I was thinking that maybe I can wire the phototransistor in series with the power source, that way when the phototransistor receives the IR, then the unit will turn on.
I'm guessing the switch would be momentary. I'm not sure where I can get a modulated IR signal or coded ir signal emitters. I have a week to finish this :(
 
That won't work, your phototransistor likely can't handle the current used by 100s of LEDs. If time is an issue at least use something like this from Radioshack 38kHz Infrared (IR) Receiver Module - RadioShack.com have it to toggle a relay or power transistor. With that type of ir module ambient light isn't as much of an issue and you could use (almost) any ir remote you have laying around to turn the sign on or off.
 
Wow, this is all very helpful! Thank you so much! :D
So if I were to use the receiver module, I can use a remote control to turn it on and off?
 
Wow, this is all very helpful! Thank you so much! :D
So if I were to use the receiver module, I can use a remote control to turn it on and off?

Just get the 38/40KHz integrated remote-control receiver module, which has immunity to ambient lighting, especially sunlight. I have seen them surplus for as little as $0.99. Unfortunately they come in two frequencies, so have to match your remote control transmitter.

If you just want to make a beam break detector that will work in sunlight, or have a range of several meters, then use the 38/40KHz integrated receiver module, and drive the IR emitter LED with a square wave at either 38 or 40kHz (must match your receiver). You do not have to "decode" a specific "command", when used as beam-break detector, the receiver "locks on" to the steady 38/40kHz signal, and the output changes state when you interrupt the beam with your hand.
 
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Okay, so I bought the receiver module, but the package says that it'll work only with voltages ranging from 2-5.5v. My system runs off 12v :(

How do I fix this? Or do I just have to buy a different kind of receiver module?
 
Okay, so I bought the receiver module, but the package says that it'll work only with voltages ranging from 2-5.5v. My system runs off 12v :(

How do I fix this? Or do I just have to buy a different kind of receiver module?

Look up a LM78L05 data sheet **broken link removed**. Don't forget the required bypass capacitors.
 
Your system may use a 12V AC adapter but I'm sure somewhere in it is a 5v regulator. Either get a separate one as MikeMl suggests or tie in to the one that's more than likely part of Velleman kit you purchased. Don't post it publicly but if you can manage to scan the Velleman schematic and PM it to Mike or I, I'm sure we can help you work in the ir on/off switch.
 
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