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Atmel RF ATmegas

Hi.

Has anyone attempted using these? I was wondering how hard it would be to use them with the arduino bootloader for my as-yet-not-started RC system project (I will get round to it soon, hopefully). The Zigduino seems to use them, and they've supplied a library to operate the in-built radio. I'm just wondering whether I'd have to be careful with PCB layout etc. to avoid interference.

Thanks in advance

PS: Here's a datasheet for one of them (PDF).

PPS: anyone know if it's possible to get USB serial out of a processing-based android app?

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The schematic and board files of the Zigduino are available on the site you linked to. If you start from a proven design it should be doable to make it?

Maybe nRF24L01 modules are an alternative? They are cheap and have good Arduino support. I've built several PCB's with a header for them.

Thanks. I hadn't thought of looking at the zigduino board layout. I probably would need to re-arrange stuff anyway (I'll probably need to make the recivers pretty tiny), but it sounds like a good place to start from. I've looked at the modules, but I'd like to try and keep single-board with the stuff.

Yes you will have to pay attention to the PCB layout when doing RF design. Not only interference but also so that it works at all.

If you want to do a PCB antenna ('just' a trace) you will have to pay attention to the track length and that you don't have to much parasitic capacitance/inductance. On some PCBs with PCB antennas you will find that there is no ground plane underneath the antenna to reduce parasitic capacitance (the power planes on top and bottom function as a capacitor with the FR4 PCB material as the dielectric).

I am no expert in RF design and have never done it (I'm just a hobbyist :P) but strange things can happen at RF, there should be an application note on this. 

Thanks. I was intending to go for an external antenna, probably one like you get on routers (WiFi's 2.4ghz, so would one of these be OK?). I'd heard that you needed to be careful with layout, too. As someone with relatively little knowledge of RF circuits and PCB layout, do you think it'd still be worth a shot?

I think this depends on how commited you are to doing this project..

Do you want to learn about RF PCB design considerations and the ATmegas with built-in RF transceivers? 

Will it save you money? (I don't know if that's relevant to you)

etc..

 

You could certainly try it, read an application note on RF design like this one: http://www.semtech.com/images/datasheet/rf_design_guidelines_semtech.pdf

You could then go on forums and ask around there and get help / get tips on your PCB design (put up an image so they can review it). I would recommend the EEVforum, they have many professional electronics engineers there and someone will definitely be able to help you.

Cheers,

Elia

Thanks for the advice & links.

For the most part it's a means to an end; I'd like to make myself a DIY RC transmitter, and these seem a good way to go about it. As with anything, I want to learn about what I'm doing, and a lot of the stuff I'll be doing is stuff I've not done before, so RF PCB design is just another thing to learn about. I'd like to get it done for as little cash as possible (Part of the reason for the project is to avoid shelling out on a new RC system), which is part of why these looked like a good idea (Fairly cheap, and does 2 jobs).

I'll have a look at the links; I've had a quick glance, and they look useful.