I attended Arcade Expo today in Southern California. Marco had a Walking Dead with Stern's new SPIKE system on display. This was the first time I saw it in person, and I had plenty of time to really look at it up close, so I thought I'd share some thoughts about it here.

BTW, who the heck am I to be posting this? I'm one of the creators of the Mission Pinball Framework, an open source pinball platform which runs on both P-ROC and FAST hardware. Stern's SPIKE system is *very* similar in architecture to what P-ROC and FAST do (lots of small interface & driver boards connected via serial cables), and since I wrote the P-ROC and FAST interfaces for the Mission Pinball Framework, I have deep knowledge of exactly how those two systems work.

So anyway, I walk up to the Stern SPIKE thing and here's what I notice (in random order):

First, that little main board in the backbox that's been on Facebook and stuff is a combination CPU & pinball controller. It's a custom board (with a Stern logo on it) which has an ARM (Amtel SAM9G45) CPU as well as the CAT-5 connectors to talk to the other distributed boards. This is different than FAST & P-ROC, as their pinball controllers can be used with any host computer you want. I don't know if Stern's choice is good or bad.. I'm just pointing out that it's different.

One thing that seemed really weird to me was that the main board had LEDs for 5, 9, 24, and 48vdc. I wonder why they're taking those higher voltages into that board? FAST and P-ROC connect the high voltages directly to the driver boards that need them.

The example SPIKE system had a switching power supply with what appeared to be three 10,000uf caps. This will probably cut 20 pounds off the weight of the machine, though I'm curious how they actually did it because I always heard that getting UL & FCC certification on a pin with a switching supply was really tough.

The power supply has been moved to the lower right corner of the backbox, and the power switch has been moved to the back of the backbox.

As for the breakout boards, it looks like driver boards support 8 drivers each (with through-hole MOSFETs), and all the switches seem to be on their own board. This means that so-called "instant response" coil activations (flippers, pop bumpers, slings, etc.) need to go to the network. (This is how P-ROC does it. FAST has switches and drivers on the same breakout boards and can therefore handle instant responses without going to the network.)

Speaking of the network, don't be misled by the fact that the Stern SPIKE system has Cat-5 cables between all the boards. That does *not* mean the boards are connected via Ethernet. The Cat-5 is just a form factor. The guy from Marco confirmed that Stern is using the CAN bus. (Maybe that's the "automotive grade" technology Stern mentioned in their press release?) This is pretty similar to P-ROC and FAST. P-ROC uses a two-wire RS-485 bus with cables you can make yourself. FAST uses Cat-5 cables with their own serial protocol.

I forget to look at the switches to see if there was a matrix or if they were all direct. Based on number of connectors, I assume they're all direct. ("Direct" meaning that each bundle, for example, of 9 wires supports 8 switches and a common.) Ironically this actually means *more* wiring under the playfield versus a matrix, but it's certainly easier to troubleshoot.

The FAST and P3-ROC boards use multiple distributed switch boards so you can locate your switch boards near your switches. This means less wiring. The Stern SPIKE system I saw today seemed to use one board for all the switches. Sure, putting it under the playfield means less wiring to go all the way to the backbox, but having one switch board instead of multiple means that SPIKE has more switch wiring than FAST or P3-ROC.

For LEDs, the example machine only had single-color LEDs. Based on the photos from CES, it appeared that RGB LEDs in Wrestlemania were direct-controlled versus serial. This also means more wiring. Some people think that direct wired are better because there are issues with serial devices in pinball machines, but meh, that doesn't really make sense because all these systems (SPIKE, FAST, and P-ROC) use serial connections between their boards.

Unfortunately I had to leave tonight, so I can't check out anything for follow up. But if anyone's watching this thread from the show then they can probably get answers tomorrow. (The Marco guys didn't know too much, but the hardware's right there for all the world to see.)