Samstag, 16. April 2016

Fan-Tas-Tic Pinball, Part 5

Adding some LEDs

I did a quick test with the WS2811 LED strand and I'm quite satisfied with the results. They are slightly brighter then the original bulbs, consume far less power and hence don't get hot. Especially under the white playfield inserts, the RGB colors look fantastic. The red inserts filter out all the other colors, so it only makes sense to have these LEDs configured for red only -- but that's not a big problem, considering how cheap those LED strands are.

I started to work on a platform driver for the Mission Pinball Framework v30. There is some basic functionality already -- but still some bugs need to be resolved.

Donnerstag, 3. März 2016

Fan-Tas-Tic Pinball, Part 4

 Rewiring the switches

There are around 40 switches on the playing field which were originally wired in a point to point fashion -- the cable management was quite impressive.

With the new electronics, switches are arranged in a 8 x 8 matrix. The row and column wires are tied together in two strands, which are routed in a serpentine fashion below the playing field. Finding a good way to keep the wires in order and organized took some time.

Some pics of the cabling `making-of` ...


The flipper buttons on the cabinet and the tilt switch (lead blob on a pendulum) was wired to a I2C port extender. The shielded white cable for the I2C is visible in the last picture.


The initial test look promising. The Fan-Tas-Tic controller scans the switch matrix and reports input changes to the PC.

Sonntag, 28. Februar 2016

Fan-Tas-Tic Pinball, Part 3

Some impressions from the cleaning process

State of the playing field Before / After

I used white spirit and spot eraser pads for cleaning and automotive wax for sealing it.

The insides Before / After

The playfield has been stripped and all cables removed. I kept the leaf-switches but will read them in a matrix configuration.
It was possible to take out the relay based control board in one piece. The new ARM based control board is already in place.

In its original configuration, the pinball contains only one single transistor which is part of a delay circuit. All the other functions were done electromechanically.


Sonntag, 7. Februar 2016

Fan-Tas-Tic Pinball, Part 2

The Fan-Tas-Tic controller

The new homebrew controller board for the pinball machine. It's general job is to read a lot of switches and drive a lot of solenoids. 

The game logic runs on a Raspberry pi, which communicates over a USB-serial connection with the controller board.

Mainboard, as rendered by KiCad

Mainboard, getting CNCed

Mainboard, tested and working
Unfortunately there was a glitch during toolpath generation of the second layer, which we only noticed very late in the milling process. While the board was functional, the high current traces for the solenoids turned out much more narrow than intended. They instantly burned up during the first test with a real solenoid (24 V, 3 Ohm, 8 Amps peak.). As a workaround I soldered thick copper wire on-top of these traces.

High current traces fixed

Driving WS2812 LED strings. Check of timing.

Samstag, 6. Februar 2016

Fan-Tas-Tic Pinball, Part 1

Refurbishing and upgrading a electromechanical pinball machine from the seventies.

Right: How it looks like now. Left: How it might end up

Taking the monster apart

Under the hood. This thing is full of relays and mechanical switches -- a lost art.
Underneath the playfield, showing the solenoids for the flippers.

At this point, the machine is in quite a bad state. All the rubbers have turned into brittle plastic, many lamps are blown, the playfield is a filthy mess and the playfield window is cracked.

We took a last video of the machine with its original electromechanical brain, before we have teared it completely apart:

Turns out it almost works. The score counting wheels have some issues. Sometimes they get stuck, sometimes the reset process never finishes.

Dienstag, 11. November 2014

Electric longboard

A large RC car brushless motor + huge Lipo batteries + a rather smooth to ride longboard = a lot of fun :)

Pictures and comments of the construction progress here:

The whole design is based on the experience from the endless-spheres forum:

Dienstag, 29. Juli 2014

Fireflys in a jar

New! Webinterface

A toy webinterface for a similar jar can be found here:
Note that it is the real deal and the jar, standing next to my window, will actually start flashing if you click any of the buttons


  • A large jam jar (Ikea)
  • Mini USB Nano V3.0 ATmega328 5V Microcontroller Board (eBay)
  • FTDI serial cable for flashing (eBay)
  • Solar cell, 5.5 V, 50 mA or larger (eBay)
  • Lipo - battery cell, 100 mAh - 600 mAh (eBay / old laptop / old cellphone, etc.)
  • 12 x tiny LEDs, different colors, the smaller the better, with ~80 - 200 Ohm series resistors, depending on how bright you want it (kit from eBay)
  • Very thin magnet wire from the coil of a miniature relais
  • SMD resistors with 1 % tolerance: 2 x 560 kOhm,  2 x 160 kOhm. For two voltage dividers to sample the solar cell and battery voltage
  • SMD ceramic capacitors, 2 x 100 nF, to stabilize the analog inputs of the AVR
  • Some circuit board, glue, prototyping wires, sticky tape 
The making-of after the click ...