Ramsey Electronics' Model Rocket Tracking & Telemetry Transmitter might
fill your bill. It's crystal controlled between 140 & 160 MHz, FM,
powered by a 3 volt lithium battery. It's available in kit form (MR6)
for $45 and wired & tested (MR6WT) for $80. Check out their website
www.ramseykits.com. The receiver can be an inexpensive vhf scanner.
Dave Close wrote:
I know that most of us are here because of an interest in WiFi, but
this message relates to a different sort of wireless. I'd like to set-up
a small network of battery operated sensors which can report back to a
server wirelessly. My target is cheap, less than $50 per sensor, perhaps
much less. I don't need two-way communication. At the receiver end, I
want the output to be through some standard computer protocol, ASCII
text or similar through a serial or USB port. I don't want or need any
fancy display on the receiver. In fact I don't think the receiver should
need to know what kind of sensors are involved.
I think it ought to be possible but I haven't found anything commercial
that fits. I see some stuff between $100 and $200 that's as big as a
paperback book. I see the smart dust stuff for even more but they also
have a processor. I have a clock with a 2-inch-square remote temperature
sensor that would work except that the receiver is hidden inside the
clock. But the whole package, including the clock, was about $30, so my
price point looks realistic to me.
Initially, I'm interested in temperature sensors, but there are other
kinds of sensor I'd like to incorporate in the future. Each sensor
should make a wireless report about every five minutes and the messages
should include a unique identifier for each sensor.
Can anyone here point me to a suitable product? If not, I'm willing to
do some assembly provided I'm confident in the design. I'm not a EE, so
I'm not going to try to design a circuit or select components.
