#creatura posts

Another 2022-present portable computer thing. This is a 1991 Corvallis Microtechnologies PC5-L. It's a ruggedized, waterproof handheld MS-DOS computer meant for industrial applications. It ran on Ni-Cd batteries and they died so now it runs on AA's I got two of them for $50 on eBay during one of those months when i impulse buy obscure electronics as a form of escapism This thing is an absolute brick. You could murder someone by hitting them on the head with this, and it would work fine afterwards. Here's pictures of its organs for anyone curious:

That thick red wire around the screen PCB is a heater. Yep there's a setting to heat up the LCD so it doesn't get sluggish or shatter when you decide to leave it in the freezer. The thing runs on a little system-on-chip thing, which is interesting to see coming from the early 90's. Iirc the datasheet says it's capable of analog video out as well as driving the LCD, but I haven't poked around enough to enable it. Might be cool to hook it up to a TV. I did, however, open those 512k storage modules and I saw some unpopulated footprints on the boards. So I ordered some of the same chips, and at some point I'mma try soldering them on and see if it recognizes the extra space. They came with two voltmeter modules, which I couldn't get to work, so I took one of the casings and made it into a USB and WiFi adapter using an ESP32 running Zimodem, since this thing has RS232 ports on the top. I also made my own charging adapter, since they didn't come with one. I see that internal PCMCIA slot, and I tried putting a CF card adapter in, and tried installing the drivers, but it didn't work. I'm not good at DOS tbh, and I know nothing of what this slot is for. I might come back to it later. I did all of this in 2022-23 and haven't messed with it since. Except to use it to talk to my Kaypro 4 '84:

Something had really gnawed one of the claws and there was green paint, and it was full of dust, so I took the whole thing apart and cleaned it thoroughly. The design is pretty cool.

There are too many things for me to list. There's hidden buttons everywhere, and this board. I have never seen a toy PCB have trim pots in any decade. What is there to adjust? And a giant exposed copper diamond. And a blob chip, on a breakout board with labelled pins. Doesn't that cost more? This thing is mechanically and electronically complicated for a toy, and there seem to be a lot of corners uncut. Very interesting. Also there are so many different kinds of screw that you have to go to great lengths to keep them organized.

After cleaning it I made an attempt at retrobrighting the plastic. It may have done something. I 3D modeled and printed a new claw, and put it on the arm. I might paint it later. There was also a broken spring anchor that I fixed.

Now there is an app to control this guy. But it relies on specific hardware and an older Android version. I found this on GitHub

Which contains raw IR data for the basic direction controls, and later they figure out how to decode all the signals. I tried transmitting with one of my ESP8266s, but had no luck. However, I found I could transmit the raw signals with a Flipper Zero through the CLI, and I put them in an IR remote file. Now I have a controller for it, though I can't control the moods or anything.

I still wonder what's up with that PCB. With the chips so easily accessible, maybe I can do some hacking?

TLDR with this procedure you sacrifice the lower loudspeaker, but the upper one will still behave as normal. Calls and other audio seem to work just fine. There is some interference from internals that gets picked up by amplified speakers, I'm sure there's a way to filter it, this is mainly a proof of concept. This is not really a guide and I do not guarantee anything at all.

I really liked my Fairphone 4 except that it didn't have a 3.5mm jack like normal phones used to have. And my car has never heard of Bluetooth. So I started joking about drilling a hole in it.

I found this green TRS jack on a USB DAC and found it would fit inside. I took this photo with a DSi camera. Originally I thought I might be able to fit both the jack and the speaker, and I had this elaborate plan to make a cut in the mainboard and move the vibrating motor elsewhere,

but decided against it because I had no idea what losing that one contact would do. I did a test and found no major issues with removing the bottom loudspeaker. If I needed the phone to be loud, I'd hook something else up anyway. I bought a second loudspeaker and horrendously dissected it.

I used a knife. If you do this you should absolutely use a dremel tool and not a knife. Unless you don't have a dremel tool

The plan is, remove the speaker part. You do not have to completely de-laminate the two layers of plastic. Just this section of the bottom layer. The top layer has pretty colors and conductive tape and contacts for mysterious purposes. Maybe antenna.

Next, you must drill the hole. We're not quite sure what the case is made of, but it probably involves aluminum. I had a drill press and clamps, but I went to my friend's house. He doesn't have clamps or many drill bits, but he knows metal. The jack barrel was like 5.1mm in outer diameter, and after lamenting that all our bits were in imperial, we settled on a 7/32". We removed all components from the chassis including mainboard and screen before drilling.

Here, we went for a hole that was centered on the middle hole of the speaker grill. However, if you do this, you will need to also remove some more metal, because the jack will need to be kind of submerged in the floor. We also had to sand down one side of the jack paper thin to make it sit flat against the back of the screen module. In hindsight, I should have marked where the jack wanted to sit before drilling. This would have us drill at the edge of the case, but it would be closed off by the phone's back cover anyway so it wouldn't matter. Just plan out your hole instead of eyeballing it.

Unfortunately, we did not get any pictures of the fit after we were done. Probably for the best, so no one has to see the metal carnage.

Once it was in place, it was time to wire it. The speaker module presses a flat flex cable up against these two contacts on the board.

I originally managed to solder to the flat cable, but then made a mistake and tore the pads, so I ended up soldering directly to those spring pins on the mainboard. I used magnet wire for everything. I just connected both the L and R pins of the jack to this one speaker output because I didn't feel like probing out the top speaker connector and running wire up there just yet. Ideally I would have a switched jack that interrupts the top speaker, but that's for later. I might salvage something from an Apple device, their jacks tend to be compact.

Hot glued the thing in place, and this is the end result. It works just great with passive headphones. I'll upload a demo video when I get the chance, I've already used my 1 video. I wish I had taken better pictures, but it wasn't very convenient.

The caveats in the beginning apply. It's also way too loud because it's meant to drive a speaker, and it's balanced for that too. I might be able to put a resistor divider on there to reduce the output volume and let a louder signal drown out the interference a bit better?

This is speloinky btw

That heavy VGA cable is just what I had lying around, I'm only using 4 wires

changed the motors. stuck some 9v batteries and keyswitches together for testing

its so much better now