SparkFun Electronics - RF Link 4800bps Receiver

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Product Info

RF Link 4800bps Receiver - 315MHz

sku: WRL-08947

Description: Sold as a receiver only. This receiver type is good for data rates up to 4800bps and will only work with the 315MHz transmitter. Multiple 315MHz receivers can listen to one 315MHz transmitter.

This wireless data is the easiest to use, lowest cost RF link we have ever seen! Use these components to transmit position data, temperature data, even current program register values wirelessly to the receiver. These modules have up to 500 ft range in open space. The receiver is operated at 5V.

We have used these modules extensively and have been very impressed with their ease of use and direct interface to an MCU. The theory of operation is very simple. What the transmitter 'sees' on its data pin is what the receiver outputs on its data pin. If you can configure the UART module on a PIC, you have an instant wireless data connection. Data rates are limited to 4800bps. The typical range is 500ft for open area.

This receiver has a sensitivity of 3uV. It operates from 4.5 to 5.5 volts-DC and has digital output. The typical sensitivity is -103dbm and the typical current consumption is 3.5mA for 5V operation voltage.

Features:

315 MHz Operation
500 Ft. Range - Dependant on Transmitter Power Supply
4800 bps transfer rate
Low cost
Extremely small and light weight

Documents:

KLP Walkthrough Tutorial
Good AVR Tutorial
Receiver Datasheet
Another Very Helpful AVR Tutorial - Thanks Eric Forkosh!

Pricing

	1564 in stock backorder allowed

$5.95	price
$5.36	10-99 (10% off)
$4.76	100+ (20% off)

	quantity

click on image to enlarge

Comments

8 comments

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	by Sharkbits +2.4 \| December 27, 2008 at 2:02 AM 0
Hi guys, This one along with the matched xmitter are not working for me :( I am using two Arduino boards to interface to them but cannot seem to receive anything. I followed every tutorial out there and nothing :( Please let me know if you had similar issues. If you got them to work and you have a hint please let me know also. Thanks.

	by shoefly +1.5 \| January 23, 2009 at 7:38 PM 0
I had started with an antenna length of 13" and couldn't get it to receive. I then cut it back to 6" and was able to receive about 40' away with 3.3V transmitter supply.

	by editkid +1 \| June 2, 2009 at 3:36 AM 0
I had some great frustration followed by great joy when I finally got these to work. It was thanks to this post on the Arduino forum: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1243851975 In case it helps anyone!

+2.3

| July 21, 2009 at 2:49 PM

–0.22

Maybe the same problem, but I don't know which side might have the problem, and I was just trying to see it using an LED - but does this have ANY drive capability? The datasheet says 10 microamps for both states.

The problem seems to be ASK or OOK, but it isn't quite that. If I keep the transmitter constantly on, I will only get a short pulse out of the receiver (if that). I would expect a switch on the transmitter would turn on and off something on the receiver 1-for-1 up to 4800 baud, but down to DC. Reading the info, there seems to be a requirement for some (unknown) switching of the data, i.e. a minimum frequency.

	by TyeScott +6.5 \| August 13, 2009 at 6:22 PM 0
I had difficulty getting correct/accurate data out of this chip. I stumbled upon this site and found it EXTREMELY useful. Now, 100% accurate data. I hated this transmitter until I found this site. Its for PICAXE but can be adapted http://quicktrip.co.nz/jaqblog/index.php?option=com_idoblog&task=viewpost&id=25&Itemid=8

	by Matthew +4.3 \| August 31, 2009 at 12:02 AM 0
the link is broken :(

indoctrin8ed

+1.2

| December 10, 2009 at 3:41 PM

These are very finicky and very suspeptable to noise. In my opinion, not worth the headache over an Xbee. But if you really want to make use of these, you must do these two things:

1. Tune your antenna to the proper length. You can use this site to calculate a suitable length depending on frequency. (http://www.csgnetwork.com/freqwavelengthcalc.html). Full wave is most optimal, but 1/2 or 1/4 is next best. You can experiment by adding/trimming length to the antennas. This will reduce your SWR. (http://en.wikipedia.org/wiki/Standing_wave_ratio)

2. Packetize your data and use checksums. On the receiving end, compute the checksum to make sure the data is clean before you "trust" it.

The device appears to do some adaptation, so if you send 10-15 "warm up" characters before the "real" data, this appears to improve the chances of the real data to be clean.

I get about 1200-1800 baud of usable data when using 4800 baud input at 40 feet indoors.

	by SteveP +1.1 \| December 20, 2009 at 12:09 AM 0
I got this working on a pair of Arduinos using the VirtualWire library. The PDF documentation for VirtualWire includes a very basic "hello" transmitter and reciever. This thread was useful: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1208473338