And another long overdue project of mine, which started with us painting my son's room

My son also wanted to have a firefighter truck painted on his wall. But since I had some electronics stuff on my mind which I wanted to try out anyway, I promised him much more than a painting.

The idea behind, is to have a somehow 3d painting, with lights, and more states of programming. I decided to go with this:

• Idle mode: all lights are off, but if the light sensor senses no light, the headlights go on 20% of their power
• Headlight mode: headlights go on 100%
• Action mode: all lights animated somehow like a real firefighter truck (see video)

Cycling through all actions is done with a touch sensor on the lower left part, near the wheel.

Step 1: Canvas and Form

First of all I tried drawing a truck and all the elements to be later implemented. My son approved every part of the project, so my motivation was maximised ;-)

I started with a normal painting canvas.

Had a lot of styrofoam plates lying around in the basement, cut them in the form I needed, and glued them on the painting canvas. Later I rounded all the corners with some sandpaper. Also for some more detail in the form, I applied some cardboard.

I new that I am gonna use spray paint to cover the styrofoam, and also have found out the hard way that spray paint eats right through the styrofoam. So first of all before continuing, I covered everything with 2 layers of wood glue with a brush.

Step 2: Spray Painting and Decoration

99% of the painting is covered with spray painting. Acrylic paintings I used only for some small stuff.

So I painted everything, red the truck, silver the front bar, black the inside and wheels, white and blue the sky.

Now the decoration part has begun. I gathered over time everything I could imaging fitting the painting: bottle caps, bottles, sticks, parts from old toys, etc.

For the sirens, wheels, headlights, etc I used plastic bottles. See the image what part of the bottle is used for what part.

I found an online service which creates customised registration numbers. I only printed them out and used them on the truck.

Step 3: Electronic Part

I am starting to beleive that lights on toys for children is like bluetooth on devices for grownups ;-).

So lets put some light in the project.

I used:

• normal leds: 2 yellow, 2 red, 2 blue
• a programmable led strip (WS2812b)
• photoresistor - light sensor
• Atmega328p microcontroller - programming
• 7805 voltage regulator
• 10uF capacitor - stabilise 7805 output
• 10MO resistor - touch sensor
• PCB board

Starting with an arduino I tried out the electronic part as seen in the pictures. Have developed the code for all 3 programs and to cycle through them.

Then I moved the code on a ATmega328p, which is the same microcontroller used on the Arduino, just to minimize the cost and size of the electronic part of the project.

Then I moved everything on a PCB board and soldered all together. This is my first time soldering everything on a board. Used only dev breadboards until now. So be gentle with my soldering skills :-)

Step 4: Finished

Put all together results in the truck you see in the videos.

Seeing my son sit in front of it and playing more then 10 minutes with it (yes, that's a lot of patience for him / his age) was all I needed to declare it a successfull project :-)