I've been working on an expansion to the Pinscape controller, and it's far enough along that I thought I'd share the plans and see if anyone has ideas for improvements on the preliminary design.
The basic idea is to create a single controller board that can handle essentially all of the I/O needs of a really decked-out virtual cab. As with the Pinscape software project, this is all open-source and DIY. The plans will be published so that anyone can build it.
The existing Pinscape controller is already pretty comprehensive in terms of input functions - analog plunger, accelerometer nudge, and button encoding. But up until now, it's been limited on outputs, because the KL25Z only has a handful of PWM ports. To overcome that, I've designed a circuit board that uses external PWM controller chips (four TLC5940 chips) to provide a large enough set of outputs for just about any virtual cab. The PCB design also includes power boosters for the outputs that can directly power all of the common feedback devices - no relays, amplifiers, or other booster boards needed.
The board has 60 outputs total, allocated as follows:
- 24 high-power outputs for large devices like contactors, shaker motors, gear motors, fans, replay knockers, and flipper coils. These 24 outputs are driven by MOSFETs that can handle about 10A on each channel - way more than enough for any of the common devices.
- 24 medium-power outputs for flashers, strobes, and button lamps, capable of handling 1.5A each. That's enough for up to three of the 3W RGB flasher LEDs, in parallel, on each circuit.
- 12 low-power outputs for 20mA LEDs, specifically for RGB flipper button lights. I allocated 12 channels for this to allow for 4 independent RGB lights, for independent colors on the left/right flipper buttons and left/right magna-save buttons.
It also has a couple of special features from my own cab that I think many cab builders would find useful:
- One MOSFET output is time-limited to about 2 seconds ON time each time it fires. This is specifically for the replay knocker, as protection against software faults on the PC side that leave the knocker stuck on.
- There's a time-delayed relay switch for turning on TVs at power-up. The relay pulses on momentarily after a programmable delay after the power comes on. This is useful if you have a monitor that doesn't turn on automatically when plugged in.
Finally, the board has pin headers dedicated to each function for easy and neatly organized wiring. The KL25Z itself just pops into sockets on the board, so there's no wiring for that - just plug it in.
The Pinscape KL25Z software already knows about the new board - there's a new configuration option to send outputs through a set of TLC5940 chips. You can use that even without the new board if you want to create your own custom hardware. I also extended the USB protocol to accommodate the expanded number of output ports. It's still backwards-compatible with the LedWiz protocol, so old software will still work with it and will still be able to access the first 32 ports. I've written a DOF module that uses the new protocol to allow DOF-aware software (like Visual Pinball and PinballX) to access all 60 of the ports. I still need to hand that off to Swisslizard, but that should be in DOF R3, so everything should just work transparently once that's available.
I have some estimates of what this will cost to build. You might be able to do better by shopping around (e.g., you can get the MOSFETs cheaper on eBay). The PCB itself looks like it'll be under $10 to fabricate in small batches, of about 10 units at a time. Hopefully we can organize group buys as needed. The KL25Z goes for $15. The TLC5940 chips are unfortunately no longer stocked by Mouser.com, so you'll have to order them from eBay, where they go for about $5 for 5. The other components (transistors, resistors, ICs) on the board add up to $65 at Mouser. That brings the total to just under $100. Not exactly cheap, but pretty reasonable considering that it does just about everything - it takes the place of TWO LedWiz's, booster boards for same, a button/key encoder, and a plunger/nudge board. What's more, you don't actually have to install the full set of parts; you only have to install as many MOSFETs as you actually use, for example. So if you're not using all of the output channels and you don't need the TV startup timer, the cost would drop a little (and you can still go back and add them in later if you change your mind).
Here's the PRELIMINARY set of plans. I haven't actually fabricated this PCB yet myself, so be aware that it's UNTESTED. I have built and tested all of the individual circuit building blocks, so I think the design is sound, but the PCB layout could contain errors that I haven't caught yet. I'd certainly appreciate any "proofreading" that anyone has a chance to do, both in terms of the schematic and the physical layout of the board. Definitely let me know if you spot anything amiss, like wires that aren't connected or parts that won't fit next to each other.
You can find the EAGLE schematics and board layout files, along with a more detailed discussion of the project, here:
Part list at Mouser.com (everything except the TLC5940 chips):
The main Pinscape software project page:
I'm going to spend some more time going over the design to make sure everything looks right, and then at some point I'll order a batch of PCBs and do a test build. In the meantime, I'd be happy to hear any feedback about the design.
Edited by mjr, 10 November 2015 - 07:23 AM.
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. And due to the poor availability of the Ledwiz here in the EU this open source project is just killer. 
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