DDR Lighting

Hi I'am thinking about buying an arduino board but have only a small amount of knowledge about electronics

What I am trying to do is light up a DDR dance mat the idea is that when stepping on an arrow a set of lights will flash on for each press, when pressing and holding on an arrow the light will pulse

I would like them to be in 4 seperate groups of 25 RBG leds or using led strips to light up each arrow

For this project you need some pressure sensors (for the 4 "direction buttons") and some lights. Your idea to use RGB leds is a good one but keep in mind that you need about 100mA each (on 5V), so for 100 RGB LEDs this is 10A. Check that you have a power supply delivering such amounts of current and you need to feed the strips at several points to have not too much current on a strip wire.

Hey pylon I have hooked up some test sensors already and they work fine when being pressed however now I need the arduino to switch on the leds once the sensor is pressed. Also i have multiple options for power supply 12v, 24v that I can plug into an outlet or a spare power supply I have laying around.

So what's your question to the forum then?

Huehue custom dance pads for DDR, we built a set for my sisters birthday a year ago. though they were basic, they had EL panels as the light source for each of the arrows, however no uController was needed, just used pressure switches same as the existing ones in a dance pad (we gutted some red octane pads for their pressure switches and the connection to go to the PS2) and jsut had them trigger the EL panels under the arrow decal that got put on some polycarbonate.

For you though, so im guessing what you want to know, how to pick up the signal when the person is stepping on an arrow. and then tell the LEDs to turn on in the manner you want (you mentioned that on stepping on it, the arrow will flash, and then if your weight is kept on it it’ll continue flashing until you release). Well if its basic and you just want them to light up. all youll need is an interrupt for each of the arrows, that upon being pressed, then run a code. Something like, turn on LEDS, wait .25 secs, turn off, wait .25 secs, turn on. and just have it repeat that while the button is pressed. Electrically, well one I wodner why you choose LEDs, how are you going to mount them in the dance pad, are you buildign a sturdy pad, or jsut taking a mat, or foam insert pad and thinking of adding the lights because LEDs won’t like being stood on repeatedly, or jumped on for that matter (hence why my project opted for EL panels, they seemed like they could take a better beating).
But like what pylon said, 100 RGB LEDs (read, 300 LEDs actually) is going to be a significant amount of power. Youll need several PWM drivers at least to drive the RGBs,
http://www.sparkfun.com/products/10136 seem pretty cheap, each can control 16 channels (so youd need 2 for each color for each pad, and then 3 pair so 6. you could have the extra pins go over and control a different color, or the lights on a different arrow, but then coding becomes more difficult.) And youll also need a power source external to your arduino and any ICs just to run the LEDs.

also i doubt any of the LEDs your going to be buying are going to be 12 or 24v. everything going to want 5. Also whats the amperage rating on that power supply. like pylon said, about 10A of power will be needed for all the LEDs on, thats a pretty significant power supply.

Would this be any easier using LED strips rather than the leds themselves? I have seen people use alot more leds with less of a power supply than what I have available surely this must be possible to do. I have seen a video with someone running 32x16 rbg leds with only a power supply of 'Power Supply 5V 7 3.7A' listed.

With these LED matrices you usually light only one of the 16 rows at a time, then the next and so on. So you have at most 32 x 3 = 96 LEDs running, at about 40mA each you get a bit below 4A. The LED strips often come with integrated control chips (p.e. WS2801 and the like), so it's quite difficult to drive them like a matrix.

So would running them in a matrix be the best option for what I need? I have no problem learning the programming its more the hardware side im not sure about

No, from you've told us yet I'd say it's probably easier to put the LEDs in series and hook them to 12V or more. What do you expect from the LEDs? Do you have to control each LED for it's own? Or just within the 4 fields all LEDs together? Do they have to change color or is one fixed color (for every field) enough? How much light do you need?

Only need to program them as 4 groups rather than individual with ability to change color (eg change square 1 to blue then green effecting all leds in square 1)

In this case it's probably best to take standard RGB LEDs (you don't need that many) and put them in series. Take care that you calculate the current limiting resistor correctly (depends on the LEDs used). To switch them on and off a MOSFET is probably best.