Project feasibility help

Projects General Guidance
1

Hello

I am completely new to Arduino, and need some advice as to whether you can do the following with Arduino.

Project 1) Independently control an array of 24 (6*4) 12v PC FANs - with the ability to turn on and off and set rotation speed. Like these http://www.maplin.co.uk/computing/pc-cases-and-cooling/12v-mains-fans

Project 2) Independently control 8 smoke machines like these http://www.soundmastersdirect.co.uk/fxlab-metal-mini-400w-fog-smoke-machine

So for each project do I need an Arduino for each device? Or can one control all of them. I want to send data in realtime to the Arduino that will affect the devices connected (turn each on and off) so if I need more Arduino than one can I connect multiples to one computer, and then how to you sync across all of them?

You are no doubt shaking your head at my complete ignorance, but any help getting me started would be greatly appreciated. Better yet if you live in the Edinburgh area and fancy being commissioned to help build the work drop me your details.

Cheers

2

For the cost of those fans you could buy one large fan with vastly more power available - either a mains fan with variable speed controlled by a triac or a car radiator fan with variable speed controlled with a transistor.

If you decide to go for the array of small expensive fans, you need to decide what level of control you need. Do you need fully independent proportional speed control of each individual fan, or of a few blocks of fans, or just the ability to switch them on and off in groups or individually? Anything is possible, but depending how fancy you get it could involve a lot of hardware and software, or just a few lines of code and a relay shield.

3

Hi PeterH - thanks for your reply

I do need an array of fans where each one is fully independent and I can control the speed of each fan. Like this project http://www.creativeapplications.net/iphone/floating-forecaster-maxmsp-iphone/. This is a prototype for a larger project but I thought it better to test the concept on a relatively lower scale before super-sizing it.

4

For your fan project, an easy way to control individual fans is to use the PWM pins to drive each fan individually through a transistor. Even the Mega only has 15 PWM pins though. You could do your own PWM in your sketch by keeping track of time and explicitly turning the other nine pins on and off as appropriate. You would just need to ensure that the code that reads the fan instructions doesn't block or delay as that would interfere with your timing on those fans.

The smoke machine project looks feasible. I suspect you have to power it up and then press the green switch to get smoke. If so, you could hack the switch (which may well be a dangerous proposition involving 240V) or rig up some Heath Robinson contraption to use servos to press the buttons.