Saturday, 27 February 2016

Weekly progress 22 - 26 February

I’m at a crucial point in my MA studies, with only a few months left till the degree show, I’ve taken some time off my part-time graphic design job to focus on my projects.

The plan for my 6 weeks off is to make goals each week and try smash them to move the project on to make it a reality, this post is a journal of what I got up to during week 1.

I'll add in a link here to a catch up on my Pinball Machine and Pinball Prints projects when I post them.

This week my basic goals were:

  • Complete wiring the pinball cabinet & powering up
  • Start accurately measured Playfield Design
  • Complete audio integration for the exchange project


Bob Leadbeater of BLM Audio helping prototype an audio amplifier for a Raspberry Pi
Monday morning started focussing on my submission for a student exchange exhibition Read my post about that exchange project brief. The final piece is a hand made print with an embedded screen. I'm on schedule with the other parts of the project, now I am working on the audio.

With some valuable advice and collaboration with Bob Leadbeater we prototyped a small audio amplifier for the project. Unfortunately what we put together wasn't fully compatible with the Raspberry Pi, so I do more research and will revisit on Tuesday. Read more about integrating speakers into a Raspberry Pi Project.
Wiring up cabinet switches to a temporary connector
In the afternoon I moved my attention to the main event, the pinball machine. I'm getting my head around making the extra switches I need for the cabinet.

Carefully studying and deciphering the original pinball machine schematics - mapping to the software
These switches are for flipper buttons and the start as well as some other switches for control. This involves quite a bit of studying of the schematics from the donor pinball playfield 'Supersonic' (1979). Every problem I solve in this project, I am finding a new set of skills and heightened level of understanding. Taking it one step at a time makes the process easier.


Left to right: 48v supply (solenoids), ATX supply (for boards, switches, LEDs), MyPinballs Control Board, Driver Board with original playfield connections.
I've been a bit wary about connecting the higher power supply in fear of doing something wrong. Luckily MyPinballs has a dedicated hardware support forum to help with all aspects of the Custom Pinball Controller board sets, which he has kindly sponsored to my project. The group consists of Jim of MyPinballs along with everyone who owns the board set and are each working on their own custom pinball machines. A indispensable wealth of knowledge! 

Planning my very simple power board based on the original pinball machine connectors

This bank of knowledge is really useful for learning how to setup the boards and how to do a specific task, such as wiring up custom power supplies. I've started getting my head around it by drawing out diagrams, translating the information I have into a way I can understand it. Colour code helps, these old pinball schematics are all black and white!

Final audio setup and draft layout

In the meantime I'm quickly dropping back in on the exchange print project, and finalising the setup for audio. Read more about integrating speakers into a Raspberry Pi Project.

Installing LED bulbs in place of the original incandescents - it's a fiddly job!

To finish off the day I made a start to installing LEDs to the Supersonic playfield for testing. The original incandescent bulbs are not compatible with the boards, due to current pull.

Pretty satisfying to see some LEDs working. Testing 5v into the General Illumination


Most of today is dedicated to wiring up the pinball machine to my custom power supply. After carefully consulting the schematics I made a temporary power junction.

Temporary power junction connector
My desk! Pretty awesome right?
When powering up the LEDs all work fine, but the flipper solenoids seem to be stuck on full power for some reason. I check my wiring and get back to the online group to problem solve. Something isn't quite right with the solenoid driver power so I'm double checking the game code & asking group questions.

I still haven't been able to get my flipper buttons working so testing with the multimeter to try find the root of the problem. I believe it is a programming issue, but could be a mistake I have made with wiring.


Production line!
I spent the morning in fabrication at uni, making alterations to frame two of my exchange exhibition prints. I basically need to build out the back of the frame in order to include a back panel to mount the Raspberry Pi, Screen and speaker.

At uni I had to opportunity to speak to the fellow MA Printmakers who will also graduate this year about a London exhibition I'm helping to organise in September.

Now a nice bike ride back to the studio for another evening trying to nail this power and flipper buttons problem. After sharing my current game coding with the group, Jim helped me find the source of both problems.

Good news first, with the flipper buttons: because I have an early release of the control boards, the direct switches are mapped to different pins on the Arduino. Thanks to the forward thinking of Jim, he had setup the files in such a way so all that required was to simple change the pin numbers in the pinball controller switch library. I can see flipper buttons in the log files. Is it wrong I'm excited about buttons working!?
The control board can be monitored by USB, great for problem solving!
Now the bad news. We had hoped solving the flipper buttons would solve my power board issue too, but unfortunately not. After a lot more testing we eventually figured out, at some stage, somewhere I had managed to fry two of the transistors on the driver board. I really don't know what I did, but I think something may have shorted, feeding 48v through my low power boards.

The power driver board and my two busted transistors closest - hard to tell without a multimeter

Here's my meter readings comparing the busted transistors to the working ones

I feel a bit silly for whatever caused the problem, but it sure is a learning curve. Although it has set me back getting the pinball machine playable, I've made some serious progress this week, and learned loads in the process.


Most of the day is spent catching up on some freelance work, keeping the admin side of working part time as a freelancer up to date - unfortunately due to the nature of working freelance I can't take holidays! Just now I have a few jobs on, including recurring work for Shetland Arts and Crafts Association and their annual Craft Trail & Members booklet for 2016/17. Also, another exciting project that is just in the sketching phase is a poster for Shetland College’s new BA Fine Art course.

I also made sure the new transistors were paid for so I can get on with replacing those early next week. In terms of completing my weekly set goals, although technically the pinball machine powered up and flipped, it wasn’t as intended so unfortunately that goal was unobtainable this week. The other thing that got left to the side was the playfield design, which ideally I want to have well underway next week. The evening was spent beginning to translate the playfield to a digital cutter template, for lasercutting my own playfield.

Carefully measuring key features of the playfield. Double checking. Triple checking. I'd love a set of callipers right now.
My measurements translated to a digital cutter file, with an early preview of some of my customisations to the original game
I'm a bit behind with this template now, but it's quite important to get it right and take my time. I've split the playfield into thirds, on Monday I plan to make progress on the middle and Tuesday or Wednesday I'll complete the top. The lower playfield looks like it will be the trickiest so hopefully I can make up time now.

It may have been noted that I’ve not been very good at sharing with you and documenting my progress on my pinball machine project. I really think this is due to the nature of it, many pieces have to come together at the right time in order for it to actually happen, I’ve perhaps been apprehensive about putting things out there and having big gaps in between updates and perhaps a slight fear of the whole thing not happening. I'm now at a point where I've made some serious progress so will continue progress updates, follow me on Instagram for more regular insights.

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