RGB LCD Arduino Intervalometer

I am getting ready to sell some kits and wanted a good way to photograph the assembly without fumbling around trying to hold a camera in one hand and a project in the other. The answer? An intervalometer. A device that can send an IR signal to my Nikon, triggering the shutter. The video above explains all of the features including; automatic delay calculation, auto stop, multiple LCD and LED feedback options, Li-Po charging, FTDI headers, and manual control via button or plug-in foot switch.

This project will work with most Nikon DSLR cameras without changing anything, but can easily be adapted to work with Canon, Sony, or any camera that will accept an IR remote.

You can get nice RGB LCD’s, as well as the foot switch at Adafruit Industries. They even have positive character, negative character (the one used in this project), positive graphic, and negative graphic versions!

Arduino intervalometer code

Eagle intervalometer schematic (Eagle format)

Eagle intervalometer schematic (PDF format)

Intervalometer Parts List (Numbers format)

Intervalometer Parts List (Excel format)

Intervalometer Parts List (PDF format)

Using PWM outputs with an Arduino and a LED

Hi everyone, been a while since my last post, but I have been a busy new daddy. πŸ™‚ I wanted to demonstrate what PWM output was and how to use it nicely in a sketch. I’m really big on ramping lights on and off (my entire house is set up that way) and would like to share how do accomplish that. I also wanted to use a video to show PWM outputs on a scope to help me explain the process.

Slide from video above

Pulse Width Modulation (PWM, but also sometimes referred to as Pulse-Duration Modulation -PDM) is the manipulating (modulating) of the width of a fixed pulse. The pulses are sent at the same voltage and frequency, so just the width of the pulse is changed. In the screen shot above the fixed voltage is 3.2V and the Frequency is 490Hz.

You can grab the serial controlled Arduino code here, or the shorter fading sketch here.

Controlling high power (or high number of) LED’s with an Arduino

A while ago I posted about my bench lights, and have gotten a number of request for schematics and code. I’ll gladly put the code up, but I also wanted to explain what I did so that others can create their own, or at least change my design up as they wish. The transistors I’m using are TIP122’s. You can find the data sheet here. They will switch a lot of power, but keep in mind, they need to have adequate cooling if you are going to push them hard. Always remember, fire = bad.

I covered the basic schematic for a few LED’s in the video above, but if you have any questions, feel free to post them in the comments and I will answer as quickly as I can.

You can download the original (controller with LCD and hard buttons) code here.

You can also download the newer (serial controlled – adjustable level) code here.

Just a note, I will be using Vimeo from now on, but I will still put all my videos on YouTube as well.

Multiplexing for a 7 year old

I have been wanting to make a LED clock for sometime and can’t really believe I never have. So I rummaged through some parts and found some nice 4 segment LED displays. I found some code for a simple clock at nootropicdesign, and it did something pretty neat. It slowed down multiplexing so you could see it, then it would get faster until it appeared “on”. It was a good sketch, but I thought, it needs set buttons, a blinking colon, and a way to trigger the multiplex slow down trick with out restarting. (and resetting the clock!) So I made this little clock and it worked great.

This was a great way to show my 7 year old (who wrote his first Arduino sketch the other night) about multiplexing. A picture is worth 1,000 words right? Well, a hands on demo is worth even more than that. After explaining how it works, he totally understood.

Then I noticed I had, sitting on my bench, some Lexan laser cut, for those little Nokia LCD’s I love so much, that had a 4 segment LED display size hole in them. I made the clock and moved some pins around to free up 3 PWM pins for an RGB LED. Because it’s always good to have a full PWM controlled RGB LED, ya know, just in case. Thinking of programming the LED different colors/brightness according to sun position. I also remembered I have a few Dallas 1307’s.. Maybe tomorrow, it’s late right now, and besides I’m busy porting software for a Touch Shield I got. πŸ™‚

If your new to multiplexing, it basically combines pins of LED’s and then through switching on only certain pins at a time, you can light only certain LED’s. If you were to apply power to more than 1 cathode and anode, you would get unwanted LED’s lighting. So how can this work? I have to light 14 LED’s just to display 1:00! What makes this work is you light one segment at a time. With a microcontroller, you can do this in an order and at a rate that’s fast enough that the human eye thinks that they are on solid. Most LED 4 digit displays found in microwaves, stoves, appliances, and VCR/DVD players are multiplexed. Its a great way to light a lot of LED’s with less pins than connecting each directly to the microcontroller. Below is a circuit diagram of the LED display I used. The link for the code is below as well, as always, hack away. πŸ™‚ Detailed pinout for Arduino are in the code comments.


Get the code here. (Arduino 22 .pde file)

Schematic (Eagle file)

Schematic (png file)

Arduino Police LED Strobes!

OK, sometimes your brain gets a little fried on a project and you need to decompress a little right? That happened a little while ago, and here is the result. I have this awesome little 10th scale 40mph+ Losi stadium truck I play with now and then, and I have always wanted to do this. While the strobe modes are manually controlled with buttons, I have an urge to crack open my 2 channel transmitter and put a little ASK radio in there. Nothing like the element of surprise eh? What I really would like to do is make it autonomous. πŸ™‚ Maybe later..

There are a few modes in the sketch, the video shows the first or “main” mode, but if you download the sketch the possibilities are endless to make calmer or even more obnoxious ones. I have noticed (not from my rear view mirror thankfully) the new LED bars on cop cars have a faster mode (almost like a boost mode) for high speed or high attention ares ie: intersections, but when they have someone pulled over, it is a slower pattern. Trust me, I know these things.

There are 20 (red and blue in: each of the headlights, tail lights, sides, and 4 red and blue in the light bar) “straw hat” style LED’s and they are driven by an Arduino and powered by a 3.7v Li-Po battery, you can buy them at adafruit.com. There is not an actual Arduino inside, just a 328 programmed with the Arduino IDE. It’s way cheeper that way. (I tend to put 328 chips in a lot of stuff) Below is the sketch for your hacking. A really good tutorial on “LED blinky modes” can be found from Lady Ada here. I actually learned a lot from this tutorial series a while ago, but still reference it from time to time. Good stuff.

Click the picture to see the full image of the truck (4.7MB) You can see how dirty it is.. :\

Download the sketch here. (Arduino .pde file)