Arduino to control batteries

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi all, I'm a new arduino user looking for a bit of guidance. I appreciate any help that can be given.

I'm currently building an interactive sound installation which basically uses pressure sensitive mats to trigger sound samples. I want to link this up with some very basic sets of battery powered LED fairy lights so that they are also triggered by the mats.

The installation is run by a max/msp patch on my laptop (therefore the arduino will also be controlled with max/msp and connected to my lappytop)

Soo....I have 5 sets of LED fairy lights (25bulbs each) that are each powered by 3 AA batteries and all I really want to do is have the arduino turn them on and off (via 5 separate outputs).

I believe the programing side of the installation is within my capabilities, it's just the electronic side I need help with.

Thanks for your time.

nick

2

Use a transistor package, or an H-bridge type setup. Transistors allow you to control a different power source easily with a 5-volt TTL signal coming off the Arduino. Sparkfun sells a package for about $2.50.

3

have a look at the blink example in the playground
there i think there is a schematic on how to connect

4

then look into the other aspects like using a transistor to power bigger stuff

5

Brillant, thanks all.

Richard, thank you so much for drawing me up a schematic!

If I'm using 5 different sets of LED lights with their 5 separate battery packs will i need a separate breadboard for each set?

Also, would the lights still be able to use the pwm outputs enabling me to fade them up & down?

Thanks

6

will i need a separate breadboard for each set?

No, but you need to tie all the grounds (Arduino, and all the battery packs) together.

If it's okay to cut up the light sets, you might want to lose the battery packs, and run them all off a single "wall wart"-type power supply (like, say, a 5V supply designed for a router or switch). It should be a regulated supply: an unregulated one probably wouldn't burn out your lights, but it might.

7

I'm not sure what you are asking?

Yup I'm note sure if I knew what I was asking either! I think I just wasn't sure if it would still all work as one big circuit.

You should really use a meter and measure the actual current drawn by the light string so that the proper transistor can be selected.

Cool yup I will.

Ran, thanks for the advice. It would be a lot simpler to run it with a wall wart as you suggested but being the electronics novice that I am I'm not sure if I'd feel comfortable using AC. I would need 15 AA batteries to run all the lights though which is a bit extravagant. Would it be possible to use fewer more powerful batteries? e.g. 3x 9v batteries. (These are the lights I'm getting ldj-lights.co.uk)

Many thanks