Mini/micro Arduino to control a digital LED strip matrix.

Using Arduino LEDs and Multiplexing
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Hi, first post, so please be gentle :slight_smile:

I am new to Arduino and despite reading quite a bit, I need some help with a project.

I fly RC planes and multicopters and have seen a few of my local club recently adding analog LED strips to their craft - I want to go a bit further and make a matrix of digital LED strips to display pictures, words, etc.

We are limited with weight, but have a ton of battery power at our disposal.

I intend to use the LPD8806 IC powered LED strip, arranged into a suitable matrix that will fit the aircraft - the LPD8806 is PWM-compatible, so controlling it should be a breeze.

Ideally, the matrix will be powered from a LiPo battery, with the microprocessor board being powered by the aircraft's LiPo (typically 7.4V and 11.1V, depending on the craft).

The controlling program will be triggered by a spare channel on the RC receiver - I have a lot of spare switches, pots, etc. on my radio - which will allow the matrix to cycle through predefined patterns. One of the spare pots can be used to change the rate by which the display cycles.

I don't have a problem with the programming or with the manufacture of the LED matrix, but I don't know which Arduino would be the right tool for the job.

Price is a factor, as is weight, so with that in mind the mini-sized Arduino boards seem to fit my requirements - the Pro Micro, Nano, even a Lilypad, would seem to fit the size and power requirements, but I am unsure about how to actually get the program from the development environment to such a device and whether such a device will have enough computing power to do the job.

My only experience with such things has been with Raspberry Pi, where your options are limited to one form factor.

Ideally, I would like the whole works to be shrink-wrapped into a package and connected to the matrix using something like a JST connector (of which I am very familiar, being into RC). If that was the case, how do I go about changing the program and updating the patterns?

My background is computing - Linux, server farms, etc. and before that programming IBM mainframe OS's, so I am comfortable with the programming and shifting bits around. I am a reasonable solder-monkey so making the matrix and packaging it to suit a lightweight aerial device is something I am happy doing.

The electrical side of powering the matrix and of passing control signals isn't a problem - I have read a number of tutorials, but they were based around using a standard-sized Arduino board, not one of the micro-sized units and obviously programming such a thing is a doddle - just connect the USB.

It's those bits in the middle I am a bit confused about.

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Hi immike

Couple of comments. The various Arduino products are compared here: http://arduino.cc/en/Products.Compare

I've used the Nano in embedded projects. Processing power is the same as the Arduino Uno. It has a mini-USB connector, so reprogramming your project would only need you to plug in a laptop with the Arduino IDE and upload a new version of your program, as with the Uno. Recommended external power supply range is 7V - 12V so fits with your spec.

I haven't used the Nano in a RC project. Might be worth checking this site and googling for any possible RF interference issues and how to deal with them - I'm thinking about RF from the Nano affecting your RC receiver - which would not be great in an aircraft :slight_smile:

All the best

Ray

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Thanks Ray,

And good thinking on the interference front! I can always wrap it in a cooking-foil Faraday shield contraption using doubled shrink wrap, it will only add a few grams.

The nano is so damned cheap and with the integral USB, I think it is the way to go.

Cheers!

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For the arduino board, definitely consider using a teensy board:
https://www.pjrc.com/teensy/
That will be as small and light as you are going to get.
Teensy is very well supported.

One thing you might consider is that you don't actually need a matrix of LEDs to produce words & images.
Since your craft is moving, you can take advantage of the eyes persistence of vision.
This means that all you need is a single column of LEDs and by controlling the timing
of how the LEDs are turned on/off you can make the appearance of having many columns

  • potentially many more than could actually probably fit on the side of the plane.

I've also some pretty amazing things done using POV on the blades of the heli & Quad copters.

--- bill

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That's interesting, Bill. Thanks.

Getting LEDs to operate on a prop going 5000+rpm is going to be a challenge, I think.

I want to build displays for fixed-wing as well - lots of real estate on my park flyer wings.

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