Would RF transmitters be feasible for wireless ‘judge’s boxes’?

Projects General Guidance
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I’ve been learning electronics and playing with Arduinos for the past year. I’ve been asked to prepare an electronic aid for my camera club: for judges to use in an upcoming national competition, when they are deciding whether an image is in or out. I have a wired design that would do (and I know I could build), but would like to know whether a wireless version would be feasible. The constraints are my knowledge, cost and time. The deadline is mid-March.

The wired version would consist of 6 boxes, each fitted with two momentary buttons (e.g. red and green) plus an LED to confirm the judge’s decision has been received. They are connected via plugin cables (6m long) to a receiving unit: a larger box with 6 LEDs (RGB or red/green) to show the number of red and green votes. . A human manually records the results. An Arduino Mega runs things, sending a signal back to each judge when a button is pressed, with a reset button for the human recorder to zero the 6 LEDs once all 6 judges have voted.

I’m sure the Arduino could be connected to a PC and the results displayed graphically, e.g. using Processing or Visual Basic. Trouble is, I don’t have the time to learn enough about the software to be confident of doing that. Next year, perhaps.

Elderly judges and cables don't always mix, so a wireless solution would be ideal. I’ve seen several interesting projects using cheap IR remotes which I might be able to learn how to program the Arduino to handle . Trouble is, the receiver will be behind the judges and they would curse me if they had to spend the days twisting around.

That’s why I looked at RF. Trouble is, I suspect that’s getting beyond my skill level. But I wondered whether this forum would be worth a try before I abandon the idea for this year. Does anyone know of a simple system which would send a ‘yes’ or a ‘no’ signal to the receiver, each transmitter with its own ID? The range would be less than 10m. Cost is a consideration, or course. Any suggestions would be welcomed!

http://www.new-zealand-pictures.com/

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The only simple way would be with Xbee. That would handle collision detection and ID for each vote.
It is not cheap however.

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Use a wired version this year. After that is finished, make a wireless version and test it in many situations before using for real.

Using IR seems very unreliable.
Using RF is more reliable, but it still could go wrong.

You could use the simple on/off (ASK) 433MHz transmitters and receivers, or the more advanced CC1101 modules. Or even bluetooth.
That would work in almost all situations. You could for example repeat the command a few times with random interval to be sure that it will be received.

When a receiver is next to a computer, it might not receive, due to the RF noise that a computer or a screen is generating. There might be other transmitters, or phones that mess up the signal.

Using RF with Arduino is something for in your own house, for example for sensors and a wheater station.
But when it should work in all locations, then I can not guarantee that it will work for every press at the buttons.

(While I was typing this, Grumpy_Mike wrote about Xbee. I think that is one of the better ways to use RF, but you should have some kind of signal that the button is running, for example sending a "I'm alive" command every 10 seconds.)

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Thanks, that's very helpful.

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Have a look at nRF24L01 radios.
Some are very cheap: http://imall.iteadstudio.com/im120606002.html
There are good examples and tutorials:
Arduino Playground - Nrf24L01

I think your project is totally feasible using radios like this.

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CAT5 cabling from each judge to the central receiver would be inexpensive and simple.

Search for CATkit shields or CAT5 Shield under the Products and Services section of this forum.