RF Remote Controls and Communication Links - Page 1
Forum section: electronics / projects

author: metalphreak
author_rank: Frequent Contributor
timestamp: January 23, 2012, 01:52:23 pm
content: I've been looking into these RF remote kits for an upcoming project (I need to send IR commands to an amplifier inside and I don't want to run cable for a repeater). I couldn't really find much info on them so I ended up buy a few different ones to see how they work. You can get kits to do low data rate serial comms but you need to write your own code to clean up the noise. A few different kits use ICs that encode data on the transmission end including a unique address, and decode it on the other end, using that same unique address. The most common are the PT2262 and PT2272 pair.To start off these are the remotes I grabbed:http://www.goodluckbuy.com/universal-rf-wireless-4-button-plastic-remote-controller-for-car-for-home-appliance-with-keychain-key-ring.html- crap quality, case doesn't screw together very well and the buttons are hard to press- uses some kind of microcontroller. No instructions on how to pair, set address etc. Bin worthyhttp://www.goodluckbuy.com/3ch-on-off-wall-light-lamp-wireless-rf-radio-remote-control-315mhz.html- seems to be ok. typical cheap plastic- uses the eV152 encoding IC. Address is autogenerated and you must configure the receiver to accept this address (!) not really usable with PT2272 receiver modulehttp://www.goodluckbuy.com/4-channel-universal-long-distance-wireless-4-keys-abs-remote-controller-black.html?- good quality hard plastic case, decent clicky buttons- uses PT2260 ic (pretty much the same as the 2262). has solder points to set a unique addressThe Receiverhttp://www.goodluckbuy.com/rfid-superregenerative-receiver-module-315-433m-9915xrf.html- 3 to 5v operation- easy to set address using solder points- $3basically, these simple non-rolling code RF things have an 8 bit address (and 4 data bits). The versions with less data bits have extra address bits (ie 10 address 2 data). To maximise the number of addresses, each bit can be high, low, or floating, so you have 3^8 addresses not just 2^8.Here's a quick vid of me testing it out. Note there's no antenna connected to the RX module yet but the range is still a good 20+ meters indoors. All you need to do for an antenna is attach a 24cm long piece of wire (for 315mhz). You can probably get 4 or 5 transmissions per second if you wanted to push binary half-byte data across it.Top LED signals that a legit packet was received with the right address. The other four leds are the data bits (D0-D3). If you hold down a button or buttons, it will continue to transmit the same sequence even if you press additional buttons.Pretty easy way to add wireless control to projects for only $7! I've seen the RX modules alone sell for more on ebay. I'm a big fan of GLBPDF Datasheets:http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2272_2.pdfhttp://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2262_5.pdfSparkfun sell these RF kits (but they don't have any encoder/decoder ICs)http://www.sparkfun.com/products/10535(also 434mhz version)http://www.sparkfun.com/products/10533(also 434mhz version)