Category: Art

The color mix master

A while back a friend asked me if I could build a custom toy for a little guy called Oscar. She said something in the lines of ”The little guy is crazy about knobs, button, switches and blinking lights. You know, the same stuff that you like.” Of course I could not pass up an opportunity to lead a new requite towards the world of electronics so I accepted. Now it’s finished and the Color mix master is born.


The basic function is that the six RGB diodes on the top is controlled by the knobs, switches and buttons below. The color mix master has 5 modes which can be cycled between by pushing the buttons at the bottom.

Mode 1

In mode one the three switches works as a way to input a binary number. The LED that correspond to the number set by the switches is lit up correspondingly. The three knobs that are colored red, green and blue can be used to set the hue of the LED.

Mode 2

In mode two the three switches works as a way to input a binary number just as in mode one. But what is different in mode two is that the all LEDs up to the number that correspond to the number set by the switches are lit up. The three knobs can be used to set the hue of the LED.

Mode 3

In mode three the switches works just like in mode two but LED color is a fading rainbow and the knobs have no function.

Mode 4

In mode four the switches works just like in mode two. The LED color is a some random sparkles in different colors and the knobs have no function.

Mode 5

In mode five the switches works just like in mode two. The LED color is a dot moving back and fourth between left and right with a fading rainbow trail and the knobs have no function.


The case of the color mix master is an old router that I have spray painted red. It had plenty of room inside after ripping out the old circuitry.

The LEDs are through hole APA106 LEDs and they function in all essence like the WS2812B that is sold by Adafruit under the name Neopixels. They have the nice ability that you can address each diode individually using only one output from the microcontroller. Each diode has a data in, data out, GND and 5V. The diodes are connected one after another where the output from one diode is the input for the next. To make the spacing between the LEDs match the holes I had drilled in the case I made a little jig with the same spacing between the holes as in the final case to use while soldering.

The microcontroller is an Pro Mini, it has the same Processor as the Arduino, ATmega328P, but it doesn’t have USB or a voltage regulator, this makes it bit cheaper but you have to take care of the usb communications and power control your self. To provide 5V power I used a standard LM7805 voltage regulator and a 9V battery. The LEDs shouldn’t be powered from the microcontroller directly because they consume quite a lot of power and you would risk damaging your microcontroller. Instead you can run power to the LEDs directly from the LM7805 as long as you remember to connect the ground to the same rail as the microcontroller is using. If you would like to build a similar device based on my code any microcontoller that can be programmed with the Arduino IDE can be used just as long as it has at least 6 Digital IO pins and 3 analog input pins.


The software is a real hack. It was done in haste to be ready for christmas and can be improved greatly. I had problems to get the debouncing library to work so every time I pressed the button it registered as two presses. There are also unused methods etc. but hey it works! The LEDs are controlled by the excellent library. The code is available at my github:

Stockholm Mini Maker Faire 2014

Here are some pictures from the Stockholm Mini Maker Faire 2014. I didn’t have much time to look around during opening hours so most of the pictures are taken before the faire opened on Sunday morning.

The most impressive build by far was done by Jonny Eriksson with his creation popmaskinen (The pop machine). Popmaskinen is an electromechanical one man band. Not suprisingly Jonny Ericsson was awarded maker of the year 2014.

Jonny is a musician/electrician/furniture carpenter and building Popmaskinen was a way for Jonny to put all his skills to the test. The heart of Popmaskinen is the spinning metal barrel called ”taktverket” which translates loosely into the pace keeper. The taktverk was designed by Jonny and then manufactured using a CNC-lathe. Taktverket contains a myriad of little holes into which little bolts can be inserted. As the taktverk spins the bolts that has been inserted into the taktverk hit little switches that in turn trigger one of the instruments to play a note. The function is similar to how a music box works. What note that gets played is controlled by the keys on the main unit and the strumming action is controlled by at what pace the the spinning cylinder is turning at.

To be able to play both in major and minor scales Jonny has built a custom two necked guitar where one of the necks is tuned to a minor chord and the other neck to a major chord. To control the guitars Jonny has mounted electromagnets all along the guitars necks and for the strumming actions. He had to rebuild the guitar three times before he finally got it just right. The casings that houses the mechanics of popmaskinen is built from MDF and the absolutely stunning finish of the surface has been achieved by using car enamel. The estethics of Popmaskinen makes me think of cars from the 1950s and the whole build screams hard work and quality.


Today I have been trying out StippleGen2 by Evil Mad Scientist. Stippling is when you create an image from little dots of the same color but with different sizes and with different density. StippleGen2 is built in Processing and uses an algorithm written by Adrian Secord. To try it out I used this classic picture of Louis Armstrong playing the trumpet. Once you load the picture you want to stipple the StippleGen2 starts crunching numbers and the algorithm continues to refine the result by applying the algorithm over and over again and the resulting image gets better and better.

After letting StippleGen2 crunch the numbers for a while I imported the resulting vector graphic file into inkscape and generated the G-code so that I could use my laser cutter to cut the image into a black paper. 2 hours and 23 minutes later I had a 20×20 cm piece of paper with about a 1000 holes in it and it looks awesome! Would be perfect for a lamp shade or just nice to put up in a window and let the sun shine through. I can highly recommend StippleGen2 it’s super easy and a lot of fun.

Laser cutting a ”ME” stamp

Ever since I built my little laser cutter I have been trying to find different uses for it. Today I decided to see if I could laser cut a stamp out of EVA foam.

Step 1, Prepare the image for laser cutting.

I decided to let my narcissistic side run loose and choose a picture of me to make a stamp out of. If you want more details about how to make a stencil from a photo check out this tutorial.

Step 2.

Generate the g-code from incscape using the laser plugin and cut the eva foam.

3. Glue the EVA foam stamp to a piece of wood and use a saw to make it a little bit more easy to use. Once the glue is dry the eva foam frame can be removed.

4. Stamp away! I used acrylic paint and a sponge to get the paint onto the stamp.