Remote switch for battery powered LED

Hi. Firstly, I'm a software man, never done an electronics project but I own a multimeter and can use a soldering iron.  So here's the problem: for my son's wedding in May (that's him in the pic), he's rented an ancient barn with a beautiful timber roof going up to 5 metres. They want to decorate it with coloured paper lanterns, hanging on invisible fishing line. I suggested lighting each lantern with cheap battery operated 10 LED strings. Problem is how to turn them on/off from ground level, say 4 metres away. So I'm thinking infrared triggered switches. There's going to be about 30 lanterns so the receivers must be cheap on components. Here's a possible example of the LED's http://mobile.festive-lights.com/battery-lights/10-warm-white-led-indoor-battery-fairy-lights-clear-cable.html   Voltage can be 3 or 4.5v DC depending if 2 or 3 battery model is chosen. I don't know the current of the LED strings,

I'm thinking I'll need to insert the receiver switch inbetween the battery pack and the LED load. Hopefully the receiver won't drain the batteries too much in "standby" as we might need to rig the lanterns 4-5 days before the wedding and it's not practical to get up to the lights again. So, long explanation... I've seen a couple of projects on this site which look nearly right but my knowledge isn't enough to make adjustments. Can anyone give me a solution from which I can build a prototype? I'm hoping I can use an old TV remote as the transmitter.
Thanks in advance for your help

Picture of Remote switch for battery powered LED
juskat (author) 4 years ago
Thanks for both these replies. The pull tab idea sounds possible. For the r/c one I'd need 30 discarded cars wouldn't I?  Also, why is ultrasound easier than IR? Is there a suitable project using that you can point me to?  I have to say I was getting quite excited about doing an electronics project, thinking that it could be good fun to build on the knowledge gained in the future. I left my story on two IR projects on this site which I thought were nearly right... https://www.instructables.com/id/IR-Receiver-for-remote-control/  and https://www.instructables.com/id/How-to-make-an-IR-infrared-receiver-and-transmit/  I also found this http://electroschematics.com/5632/ir-switch/ which looked closest and simplest but it goes on for 3 mins then off, which isn't much use (and the author is no longer available).  I was hoping that one of you pros would give me a clue how to tweak one of these to meet my needs, then I'd build a prototype. Of course I don't know how difficult that is yet. Thanks again.
caitlinsdad4 years ago
I would go with the trick that they pack cheap electronics with. Have a paper pull tab that is attached to a long string and inserted between the batteries or battery contact. You may have to cut a slot in the battery case but relatively no cost or complexity. Just tug on the string to activate since it will be done only one time at the start of the event. Good luck.
Goodhart4 years ago
Well, if you were great with electronics, I'd suggest hacking an R/C unit for a discarded r/c vehical, etc. Easier, if you want to do it from scratch, are ultrasound devices (like garage door, car door openers/lockers, etc.