Multiple Displays

I’ve been wanting to put something cool in my pinball build, so I’ve been marinating the idea of changeable targets, or at least making the targets’ context obvious to the player. You could have a LED on or off, or color-coded, but that doesn’t really explain much about what’s going on.

So I bought a few (well, ten actually) TFT LCD screens with micro SD card slots on the back. I can load images from the card to display on the screens. One Arduino can control multiple screens, with each additional screen requiring only one additional wire (two if you count each SD card). My idea is that each game mode can reset the screen next to each target.

One technical challenge I ran in to was the wiring of the RST pin on the ST7735 display board. Examples everywhere call for it to be wired to a digital pin on the Arduino but if you do that, each additional screen you initialize or write to will reset the other screens. The trick is to take all the RST pins of the displays and only connect them to the RESET pin of the Arduino.

All the (Cabinet) Things!

Motivated by the rapidly-approaching Pinball expo in early June, I’ve been working on my cabinet. And I’ve also learned a bunch of new things, like how I mitered and glued the sides on wrong! I have a fix, but it’s going to take time I already didn’t have.

It looks like I know what I’m doing, right? Well, one more order of parts and I’ll see about getting it all buttoned up.

CAD thoughts

I’ve been bouncing around looking for a decent CAD program to use as a hobbyist. Many exist, and some even have free or reduced prices for makers and hobbyists. My makerspace has BobCAD which is a great, intuitive program. But there is nothing for the hobby user that can’t pay hundreds of dollars a year to license. I even work for a company that makes CAD software (which only marginally fulfills my personal needs). I have settled on QCad and am quite happy with it. It only took me a couple hours of reading to get up and going with it. I don’t need 3D or CAM, but I need DXF support. For about $50 you can get a professional license and a copy of the pdf user manual (half off if you add it to your license purchase), and I now heartily recommend it.

Missing Parts?

Nobody tells you all the little things you’ll need putting a pinball machine together from scratch. Or the order in which to do things. This has been a figure-it-out-as-you-go project for me, and to be honest mistakes have been made. But when buying homebrew parts, why don’t they give you everything? My coin door didn’t come with the carriage bolts to mount it (they have a square profile under the head of the bolt so they don’t rotate), and my cabinet legs don’t have the leveler/feet included either. I wonder what other parts I have but yet haven’t gotten to use yet are going to be the same?

Pinball Finds a Way

Not, I’m not dead. Neither is my pinball project. It’s just…you know. Everyone knows. The last two years…

Obviously the Boston thing didn’t work out in 2020. Or 2021. But the Tacoma expo is on for this June and I really want to have something to take with me. Visit my project site for specific pictures and updates. I have a number of things to get on track, some cabinet finishing work and a new widebody playfield. Maybe some sound and lights. We’ll see how far I get.

Well Well

So Green Mustard announced an InvaderCon 4 this August. I guess I’d better get back to work on this project! I’m in need of an artist if there’s anyone that even reads this, I need cabinet side art soon or else I have to disassemble things later to add art to the sides.

There’s little to no chance of me bringing this to Boston in August though, transporting a pinball machine almost 2800 miles would be costly (I’d have to rent a van or truck or something, not to mention the drive both ways) or else I’d have to take the risk of shipping it freight. Sad, but it’s a tough situation. Now if there’s an InvaderCon 5 on the left coast…

Cabinet Joints

No, not those kind of joints. I’ve cut out most of the wood that I need for the new cabinet, but I’m waffling on how to join it together. The inside corners all have metal braces because that’s how the legs attach (through the corners and into the brace’s threaded receptacle). So even if you just did a butt joint you would have a pretty solid cabinet. Cutting a 45° miter looks a lot better, but you have to set it up right or you get a sloppy corner. But you’re still just glueing two flat surfaces together. Going to the top of the line joint, you’d use a lock miter which is an angle plus slot and tab that fit together, but that’s even harder to set up (if you have the right router bit). So I thought maybe a simple slot cut perpendicular to the miter that I could glue a strip of 1/8″-thick wood could be a good locking method. Here’s a picture of what I mean:

I’ll call this the “long biscuit miter joint” for lack of knowledge of what it’s actually called.

It should be plenty strong, but there’s a part of my brain that keeps saying “if you’re only going to do it once, do it right.” So maybe I’ll end up with a real honest lock miter joint. I’m going to work on it tomorrow and see what I come up with, and practice on some scrap.

Wow. Just, Wow.

I can barely believe I already have “version 2” (with larger Molex connector) in hand! These shipped out from ShenZhen YESTERDAY. And daddy didn’t pay for no overnight overseas shipping. Fantastic! Check out JLCPCB, this won’t be the last project I use them for!!


PS Version 2.1 with a smaller Molex connector is just shipping out now, so I’ll probably have it Monday or Tuesday.