Using RF remote to control LEDs

[aderrainc]

I'm trying to figure out a way, or find someone to help me, create a bracelet equipped with LEDs that can be remotely controlled using RF. The idea is to have thousands of these bracelets in the crowd at a concert, and I can control the flashing of all the bracelets with one controller.

 

[Sceadwian]

A Zigbee module might work, but it depends on exactly how large the space is as well. I hope you got cash, if you found someone to make them as cheap as possible you're looking at 5 dollars for a zigbee module, 5 dollars for a battery and 2-4 dollars for everything else (I'm just guestimating) So figure 15 dollars per bracelet that's 15,000 dollars for 1,000 people.

There are other methods that might work as all you're doing is trying to sync all of the bracelets, a simple micro controller and an ultrasonic receiver could be made much cheaper, probably in the 2-5 dollar range, a single large transmitter, or a network of smaller ones (much more practical) would send out a sync signal, as this is powering LED's line of site is assumed and a local oscillator could be used to keep time in the short term if the sync signal is lost.

 

[aderrainc]

Thanks for the info. Do you think some sort of ultrasonic receiver/transmitter combo would be a more cost-efficient solution to RF technology? This system needs to work in an arena setting, and ideally would only require one transmitter.

 

[Sceadwian]

Define arena... Exact numbers for distance is very important to figure out what's best.

 

[aderrainc]

Let's call it a 45-50 meter radius.

 

[Sceadwian]

150ft isn't bad. Ultrasonics might possibly work, there would be a slight lag but it would be low enough to not be very noticeable. IR is a possible sollution as well, as the bracelets need to be out in the open to be seen which means that they could have an eye which a transmitter could be seen. All you really need is a good local oscilator and some garunteed that not more than 5-10 seconds will pass when the receiver device losses sync with the transmitter.

The light show itself would be permenantly encoded on a micro controller, the transmitter/reciever would just be a master sync so they all went off at the right time.

If you need true active data send/receive zigbee should work at that range, but the module cost is going to be pretty heafty en massse..

It's an awesome idea though. I'd say go all in find someone to make this for you and go with a cheap zigbee approach. The receiving units need to do little more than ensure they know what their serial number is and the master unit can then send data to one or all or groups of them with very little actual transmitting.

If any of the concepts I'm blathering on about are confusing please let me know, I'm not known for my ability to explain complex things in a simple manner =>

 

[nickelflippr]

I always thought that modifying one of those led style glow sticks would be kinda neat. More specifically, introduce a small micro and a rgb led. The battery would need an upgrade, and of course the rf part. Wouldn't using one of those cheap Hope rf receivers be the way? Zigbee would have the better data rate, but sure seems expensive. Any which way will not be super cheap, depending on the number, brightness, and type of led required.

I've played with the MSGEQ7 a little, and could be a possible candidate for the master micro beat to the music. The seven bands give plenty options on which frequency to use at what times.