I have been scouring the web trying to figure something out. And I found your page, and you seem to be the group of people to talk to. So...
I want to make a bunch of simple circuits that will basically have wirelessly controlled switches. I am thinking the cheapest way to do this is to have IR receivers that operate at different frequencies that can be controlled with IR transmitters. So, my questions is, if you wanted to make, let's say three switches, would you use receivers? And say, some IR transmitters with different frequencies like 36, 38, 40kHz? Or would you use phototransistors and different wavelength IR diodes? Or radio?
I have found this page on Alibaba: http://www.alibaba.com/product-gs/541465116/IR_Receiver_led.html
Where could I find these chips in bulk? Seems like it might be a pain shipping them from China. But maybe the cost savings would make it worth it.
Use a 38kHz receiver for all devices, place a ATtiny inside to decode the remote control signal and trigger a relay and you’re done. Why receivers and not IR transistors? Because the receivers filter out unwanted signal and not trigger falsely.
Ok, my issue is I want to make these as cheaply as possible, and I want to make maybe 1000 of them. So if I could just trigger these with the frequency, then I would save some serious money, right? It looks like including the logic component will cost an additional dollar per unit? Or can I get these for less?
Thanks for this tip though, I was not aware of the ATtiny!
Instead of using different frequencies you could also make an IR master/slave bus where the master emitts IR commands and the slaves resceive the commands and act accordingly.
To achieve this you have to set up a protocol, where clients get an address and can read data from the bus if the own address comes in the envelope. Have a look at this one if you want to find out more.
You’re basically flashing the IR LEDs in a binary pattern where address and commands are encoded into the pattern.
Wow! It is so nice to see an active forum. Sorry I’ve been away for a few days.
So, this is more info about the concept. I want to around 1000 units, each with a few LEDs, let’s say RGB. I want to be able to switch between the LEDs. My thought was to have a few phototransistors at different frequencies, one frequency for each color. So that if one were to shine an IR beam at the units then one would be able to “paint” with the corresponding color. The controls (emitters) would be embedded in flashlights with a corresponding color film, so red flashlight would trigger red LEDs, but really it would be an invisible light that would trigger the LEDs.
If the ATtiny can be had for cheap then it may make sense to use 1000 or so of those. But if phototransistors can be had for cheaper, and used as simple switches, then I may want to go that route.
I would probably still need some other unit to act as a switch so that only one color at a time would be triggered.
Thanks for the suggestions so far. I will update this thread as I work through the issue! Any further advice is appreciated!
building a huge paint display. If that is the case, you may consider something a bit more involved; a ‘wand’ that has a corresponding RGB led that can have its color adjusted and then a trigger to send that data via IR to the receiving wall. Just a thought.
PS - I failed to mention the wall component. With a uC on each LED/set of LEDs, you could read the incoming data and pulse the proper pins to get the requested color.
Would you happen to know if the ATtiny is the cheapest chip capable of being an IR decoder available? This will be my first time using a chip with an instruction set outside of a canned assembly course, so I don’t want to waste time running down dead ends trying to get something working.
