Arduino based high power LED light with audio sensor and DMX

[neltnerb]

Do you think that there would be interest in such a device?

The plan is:
- Based on the Arduino Leonardo to allow for more interesting USB device hacking.
- Would have DMX connected to the now free USART.
- Would have a four color high power LED (RGB+white at 700mA per channel) along with power electronics controlled from four arduino PWM pins.
- Would have a Xbee/RV-XN header for attaching a wifi module if desired.
- Would operate from a 3A, 5V wall wart since USB can't handle the current for the LED.
- Would include an on-board microphone connected to a LP3950 audio analysis chip.
- LP3950 outputs would be converted into analog signals connected to the first three analog inputs on the arduino.
- Would have an extruded aluminum case for heat sinking.
- Would use all surface mount parts where possible to make the heat sinking easier.
- Would have standard arduino shield connections for extending the system.

I think the total cost would end up at around $50/each. It's a lot, but I'm curious if folks think it's worth building.

I could also with minor modification make it a four LED per channel system using a 24VDC, 50W wall wart, although it would be a substantially more expensive toy. But it would be brighter than most commercial LED light fixtures and likely cost around $100.

I really like the idea of being able to turn it into a MIDI device and control via USB, or else use it as a DMX controller itself with a big chain of lights, etc. Seems like a lot of people might find such a thing useful for art projects and the like.

[TonyD]

Yeap, I think there would be interest.

I would like to see a IR interface for a remote control added to the design.

The LP3950 looks a cool chip if slightly expensive at ~£3/ea, the idea of syncing the light output to audio is great :-)

[neltnerb]

After I posted, I found this chip, which has been used in other arduino projects:

http://www.mix-sig.com/index.php?option=com_content&view=article&id=145%3Amsgeq7-&catid=52&Itemid=55

Seven band equalizer which outputs a DC version of the amplitude in each frequency band with peak detection and gradual fall off intended for VU meters in cars. Looks like it would take just one analog input and two digital outputs to operate it, and it'd give more bands of detection more easily than the LP3950 (I originally suggested it because I'm using it in another project).

I think that beat detection should be pretty easy to implement on the arduino if you have a live feed of the amplitude in different frequency bands -- perhaps you could have 7 lights, each assigned to a different band, and each of which shines a color from red to blue depending on the intensity of the band, plus drops the saturation if the volume rise is fast -- so a quick sharp noise would be white, otherwise a VU meter, or something like that. Lots of easily impelmentable userspace algorithms so that people can see what they like the best.

[neltnerb]

As a followup, I've finished schematic and board layout, and it looks pretty fantastic. The version I now have in hand has:

- Xbee/RN-XV header.
- USB for programming and communication.
- DMX input and output.
- 425 lumen RGB+white LED.
- Onboard microphone and audio analysis chip that sends 7 band DC amplitudes for each frequency bin.
- All SMT components so that the entire back can be rigidly attached to an aluminum plate for heat sinking.
- 4.3" x 2.5" footprint (conveniently chosen to fit in the smallest of my favorite LMB Heeger Case - http://www.lmbheeger.com/products.asp?catid=68)
- Automatic switchover power to allow programming over USB (as long as the LEDs are not activated since they'll blow the USB port...)

I'm really getting excited about this one. I had to toss out the shield connectors because of the footprint and routing difficulty, so I might try to put at least a subset of those header elsewhere, but even without a shield you can do all sorts of cool stuff. You could turn it into a USB->DMX converter and light to control a bunch of other lights from a single computer. You can make them all wifi and control them with OSC like I did in a previous project. You can program them to do complex analysis on 7 frequency band intensity information for incoming on-board collected sound. You could have it use that sound to send wifi data to a computer for analysis, and then use the computer to send data back to tell the board what to do. Or use the microphone and wifi to send data to a computer which uses it to do other visualizations along with the LEDs. There seem to be so many cool possibilities!

Best of all, I think I can make them for around $150 in small quantities, and as little as $75 in large runs! Totally worth it for me, although I guess time will tell if other people want them!

Very excited :-D

Attached preliminary board layout and schematic pdf files.