Nordic nRF2401 RF 2.4GHz Tranceiver

bulkhead

I'm just getting started with the prop and I'm looking to use these RF modules to set up a communication link between my PC and prop. I noticed there's an object class written on the object exchange page already. I have a few questions about using these RF modules for anyone who has used one or who just has prop experience.

1) Is all I need to get a working link two of these modules from store.qkits.com/moreinfo.cfm/TXRX24G?

2) Must pins 30 and 31 be used to send/receive data on the propeller, or can other pins be used? If so, does it interfere with programming? Does the module need to be disconnected when programming the prop?

3) If I were to connect the tranceiver on the PC end through the serial port, is it just a simple connector/adaptor fix? Or are there other components necessary?

Mike Green

1) You can't use these modules directly for communications between a Prop and a PC. They're designed for clocked synchronous data, more like SPI than anything else. The logic levels and power supply are compatible with the Prop, but you'll have to construct some kind of interface for the PC.

2) Pins 30 and 31 are normally used for a logic level asynchronous serial programming interface. Once programming is complete, these pins can be used for other things, but it's normally easier to dedicate them to some kind of asynchronous serial port. These RF modules are not compatible with the programming function.

3) You will need some kind of interface to attach one of these RF modules to a PC, it will probably need a microcontroller to convert the synchronous serial data to standard serial data and some kind of power supply (could be powered off USB using a 3.3V regulator). Alternatively, you could do some custom I/O driver programming on the PC ... I wouldn't recommend it unless you had a lot of experience.

I don't recommend using these modules. For a little more, you could get something designed for an asynchronous serial port that you could use on a USB port with something like Parallax's USB2SER interface or the PropPlug. Another option would be something like xBee which would automatically take care of error checking, retransmission, etc. You can get an xBee adapter that directly plugs into a PC's USB port. There was one such unit advertised in either Nuts and Volts or Circuit Cellar recently.

simonl

bulkhead,

I bought a couple of these from Sparkfun, along with their breakout boards, but unfortunately trashed them (both!) when trying to solder them to the breakouts - their pins are dual row and spaced at about 1.5mm!

I'd agree with Mike, the XBee's are much easier to use, and the Sparkfun breakouts are simple to solder too!

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Cheers,

Simon

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www.norfolkhelicopterclub.co.uk
You'll always have as many take-offs as landings, the trick is to be sure you can take-off again ;-)
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