SparkFun Forums 

Where electronics enthusiasts find answers.

All things pertaining to wireless and RF links
By geb
I'm a beginner level tinkerer (electronicswise). I find myself wanting to switch something across the room wirelessly. I have a spst contact here. There is a spst contact over there. I'd like to link them with RF.

First thing that comes to mind is the X-10 wireless wall switches and receivers off the shelf at Home Depot. It does the trick, but is expensive and I don't know how much hacking I'd have to do to simplify it to my needs.

Next thought is the junk garage door opener under my workbench. With a remote control in one hand I could remove the receiver from the board on the opener and... ok this is getting messy again.

Then I noticed the WRL-07813 and similar at the sparkfun store and wondered how easy it would be to set this up? Is it simply a matter of wiring the switch to two points on the xmitter board and then a relay to two points on the rcvr board - give power to both boards and away I go?
By riden
You cannot connect the transmitter and receiver like you stated. Some form of encoding/decoding is required. If you want a simple out-of-the-box solution, I'd recommend adding a Holtek chipset to handle those duties or one of the encoder/decoder sets from Reynolds. Painfree and reliable. I have a RF link that use Rentron's encoder/decoder chipset connected to the SparkFun tx/rx pair.

Here is a link to get you started on your search:
By geb
That is pretty much what I was referring to with the x-10 home control products. I've seen them. They do pretty much what I need.

I merely anticipated having to tear them apart and fiddle with extraneous gee-gaws inside and then try to shoehorn the results into my project. I was hoping that I might find a simple all purpose RF xmit/rcv IC out there with say eight pins. Power to a couple of pins, antenna to another, and switching across two more. Same thing on the other end. Good to go. Hopefully even less than the off-the-shelf x-10 stuff and much more compact for my purposes. I guess I'm still wondering if the last link I posted fits that bill.

Like so many other things I've searched for recently - seemingly simple propositions - it ends up being somewhat less than simple. I don't know why.
By lyndon
If it''s just across a single room, I'd think of using optics before RF. Just like your TV remote control. Generating the signal is trivial and you can purchase the Sharp remote control receivers all over the place: Sparkfun may even have them.
By geb
Just across the room was actually a figure of speech. Ideally, I'd like to go around corners and even through steel partitions. I'd like about 75 feet range through obstructions.

Oh well. Guess I just got to keep lookin around.
By geb
I ask what ought to be a really simple question.

I get a number of perfectly good, well intentioned, responses..... that eventually just get further and further from the original goal..

I reiterate my needs.. I'm ignored.. I think "what the hell, this is electronics 101, no?..."

I realize that seven year olds in Japan and southeast asia are probably doing this stuff just for kicks and i can't get a straight answer from the wealth of internet community that I have google access to... and think... what the hell is up with that? I went through this some months back in these forums trying to figure out how to implement an LED thermometer into my project. I finally did it. Entirely on my own. After dozens and dozens of hours wasted in these forums. What the hell is up with that??

This is really simple stuff folks... for anyone who has any background at all in electronics. Where are you? I'm a metal fabricator/welder. You need help with that? I'm here! Never touched a welder? I'm there for you. I don't care if you're an idiot. You came here to ask a legitimate question. Doesn't anyone have any interest at all in assisting a man with very little electronics skill to work through part of your basic skill set?


Go ahead moderator. Just kill me for Christ's sake! Ban me! I'm can't take this cruel world anymore anyway!
Last edited by geb on Tue Oct 16, 2012 10:24 am, edited 1 time in total.
By rmteo1
Here is a ready made solution for $38 that could get you started: ... ROL/1.html
Wireless 4-channel remote control. Switch on and off four separate devices, computer accessories, auto lighting, landscaping or other electronic applications. Four receivers in one package. Each operates 12Vdc, up to 6 Amp load. Receiver is 3.25" x 2.97" x 1.22" thick. Hand-held transmitter has four sets of on-off buttons and a telescoping antenna. Transmitter operates on 12V alkaline battery (included).
By lyndon
Part of the problem may be that you assume this is "really simple stuff...electronics 101." It isn't. Wireless radio communication is full of hidden complexity and trying to avoid that isn't going to get you far, which is why I offered the simple optical solution. OK, that won't work for your updated requirements.

riden already suggested a solution that he knows will work. What's wrong with that one? I can suggest using Bluetooth since it's what I know, but much overkill for a simple on-off switch.

The Linx modules you mentioned will probably work. You didn't get an answer probably because no one who read the thread has experience with them and doesn't want to lead you down the wrong path.
By RonnyM
I haven't worked with the Linx modules you describe, but I have dealt with Rentron,and Linx and they can be taken at their word if they say it is easy to use. As far as learning curve, I think this is the reason most of us are here. I hate to admit the disappointment I feel when I build a project and it works the first time! Of course it's not that often.
Unless you buy a button to relay plug-in-system, you will be dabbling in the black art of RF alchemy, and forced to rub some brain cells together.