# Radio activated on/off switch

TL;DR: I want to know if there is anything, That on which when a radio frequency falls, and it turns on an LED. Basically an on off switch but controlled when radio waves hit it.

What I hope to achieve is that, I want to have a remote of sorts, And when I press a button, the LED turns on. Without having line of sight.

Why? Because my dog and I play fetch at night, (Don't ask why I have many reasons to. If I could at day I would've but can't.) and I almost always lose the ball every night into the bushes and it's too scary to look for it. I have lost many balls and it's become annoying and expensive to lose balls every night. (I'm a student).

What I have in mind is the idea that I could press a button and it transmits radio frequency and when it hits the ball the LED turns on so I can see it.

I know an Arduino could be used to do it - I found blinking codes for it too but I can't fit it into a ball and even if I did my dog would crush it in his mouth. (And also I don't know much about coding so I'd best avoid it.) So ideally I am looking for something really small and simple that would be inside the ball so if even he bites it there's a good chance he won't crush it.

What I want to know is, is there anything that is available like what I described? A switch that, when RF falls on it, lets current pass through it like a switch allowing the LED to turn on bright so I can find it? Does anything like that even exist? I can find voice activated clap/sound/light/heat/temperature/IR everything activated switches but not this. Enlighten me.

• FYI: Product recommendations are off-topic here. Ask about design. – Bort Oct 18 '18 at 19:38
• @Bort Im so sorry this is my first post here, i did see it in the rules but never thought i had asked for that, I am really very sorry. Can i edit it off? – Shah Oct 18 '18 at 20:27
• You can either edit your question to be about design, or delete it all together. – Bort Oct 18 '18 at 20:33
• is it okay now @Bort – Shah Oct 18 '18 at 20:38
• if it is scary to go into the bushes, then how is it less scary if there is a lit LED in the bushes? – jsotola Oct 18 '18 at 20:42

## 1 Answer

Why not have the led on all the time? You can do that with a coin battery and an LED and the total cost is not much. Here is a link to an article on how to make what you need. You could leave the magnet off because it will be inside the ball.

• Never thought about that ... Ill do that if i cant find a solution to my problem. But Lets wait if can get a solution to that Because dont you agree that would look very cool and i might learn a thing or two about electronics along the way, Thanks for the idea btw! – Shah Oct 18 '18 at 20:22
• you could build a low power flasher so that the battery life is increased ..... google low power flashing led – jsotola Oct 18 '18 at 20:47
• There are already flashing light dog fetch balls on the market. The main issue is standing up to chewing. – Chris Stratton Oct 18 '18 at 21:21