I’m really knew to RF stuff. I am making an autonomous blimp and a ground station. The blimp has a bunch of sensors that read data, and send these measurements/sensor outputs to a ground station (that has a laptop), wirelessly. I want the blimp to send signals to the ground station, whereupon the ground station figures out what the blimp needs to do, and then the ground station sends signals back to the blimp to control its thrusters or control surfaces. So I figured I need two transceivers, or two transmitter/receiver pairs to do this.
So far, I’ve found the SFE - RF Link - 2400 bps - 315 MHz, SFE - Transceiver MiRF 2.4 GHz, and the XBee transceivers. My question is which should I use for the blimp? Anyone know how to make this decision?
Note: in terms of requirements, I want small and light, and preferably cheap.
Well, I don’t know about data rate. I am looking at indoor applications though - so no more than 50 ft for now. Greater range is a plus, but not a must.
At less than $20 each for the XBee (not the XBeePRO) you won’t go wrong. Range is up to 300ft., line-of-sight. You should be able to do it with just on transsceiver in the blimp and one on the ground station. RF datarate is 250,000bps and should be plenty for your application.
If you need greater range, up to 1 mile LOS, then you can always upgrade the XBee’s to the PRO’s - about $39 each.
I mean, this one’s way cheaper. Sure the bit rate is less, but does that really matter for small-time applications? Also, the blimp’s not going that fast.
I could spend $20 on a pair of the regular RF links, or I could spend $40 on a pair of XBees. What’s so good about the XBee? :S
Hmmm, thanks. I think I’ll just stick with regular RF. It seems like a safer bet, I will probably learn more by starting closer to the grass roots, and it’s cheaper.
The key difference is that with the basic wireless links you’ll need to develop your own encoding, decoding, error detection and retransmission protocol and implement them in your software. How robust (and complicated) they need to be depends on how tolerant your application is to corrupted or lost data.
With the XBee (or other commercial solutions) you get a communications stack built-in that ensures that the transmitted data is correctly received.
etracer:
The key difference is that with the basic wireless links you’ll need to develop your own encoding, decoding, error detection and retransmission protocol and implement them in your software. How robust (and complicated) they need to be depends on how tolerant your application is to corrupted or lost data.
With the XBee (or other commercial solutions) you get a communications stack built-in that ensures that the transmitted data is correctly received.
i.e. plug-and-play, like a dial-up modem. How’d you like to figure out how to code up the DSP in a dial-up modem! Same principles for wireless. Too often, I see people go for a $9 data radio and then weeks later, the light comes on as to what’s missing.
Sounds good ta me. I’ll give the $9 dollar transmitter/receiver pair a shot first. Just to see what it’s like. If I can’t get it to work, then I suppose I’ll have a pretty convincing case for me to purchase an XBee.
