Apple Keyboard II Modification

The first computer my family owned was a Apple Macintosh Performa 550, which died before I was able to revive it (I had played around with the registry too much and killed the OS). The computer was tossed/recycled, but without the keyboard.

I picked it up and kept it at my desk, figuring there'd be a way to hack it to work with USB or something, but it sat for quite some time before I actually looked it up.

I was right, there's an ADB (Apple Desktop Bus) to USB convertor that can be made with a Teensy 2.0, and also a pre-made one by Griffin (which seemed to not work very well). Last month I finally broke down and got the Teensy 2.0, but didn't do anything with it besides grab the 1k ohm resistor that I would need for the mod.

When upgrading Triela to Windows 10, I got bored and decided to work on the mod, first with the wires and resistors. I used 22 AWG wire, and I noticed that the resistor legs were just thin enough to enable sticking in the hole with the wire. It was a lot easier said than done, but I managed to do it with it looking fairly nice.

"Top" and "bottom" of the Teensy 2.0 with the wires and resistor (the shield drain wire is being used for GND, but is hard to see).

After soldering, it looked quite nice.

"Top", "bottom", and the unit ready for the next step.

I then figured out the pins on the keyboard, checked numerous times, and soldered the wires appropriately to some filter/isolation block thing (because it was easier than de-soldering it).

Closeup of the solder-work, board overview, board in its proper location.

I then played around with the casing to see how much free space was left, which was quite a bit, and the location I figured worked just as planned.

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Teensy 2.0 lined up to some pre-existing groove, spacing inside (nothing close enough to short anything), cable plugged into the Teensy (with the ferrite choke being held by the ground strap thing, and the inside view.

I loaded the firmware to the Teensy and got nothing, and trying different firmwares also yielded no results. I checked the pinout again, checked the resistor was across the correct pins, checked the Teensy itself with the LED flash firmware, and then looked closely at the keyboard PCB. I found absolutely nothing visibly wrong.

I then played around with a multimeter and looking at resistances and found there was absolutely no resistance reading between the voltage in and ground pins of the keyboard's microcontroller ("OL" on the display, not a short). From what I kinda remembered from work, there should be some resistance between those pins, but there wasn't anything. Now that I think about it, I don't recall if I changed the resistance reading range or not.

Anyway, I was a bit upset that the microcontroller was dead, since I wouldn't be able to revive the old keyboard. I'll have to check again with my auto-ranging multimeter, but I'm fairly certain the microcontroller's dead. If it is confirmed dead, I'll probably use the Teensy 2.0 for a PS/2 to USB convertor instead.

CFS

Late last year, sometime after learning SSHFS, I realised that it would be very convenient to have a centralised file server. Yes there is the NAS, but I prefer using it for backing up, considering RAID 1.

Anyway I bought another Banana Pi and hard drive, and poked around Amazon to find a box sized appropriately. Once I had all the parts, I got to work. I used the fan from the smaller Raspi "case" since it was the best option. I did a bit of prototyping and figured out the best locations for the Banana Pi and the fan, drilling the mounting holes soon after confirming.

It took quite a bit of time and effort to get the hole for the ethernet lined up correctly to cut, and after was finished cutting (not much less awkward than the double drive pi), I realised I cut too much, so placed a piece of tape on the inside, so that not much air would enter from the ethernet hole. For the power cable, I drilled a couple holes next to each other and cut out the plastic in between them before cleaning it up with a needle file. Once I was done with that, I taped the mesh over the intake hole and began prototyping a bit more.

Inside view, intake hole, fan hole, power and ethernet holes, and inside of the ethernet hole.

While the power cable fit just fine through its hole, there wasn't anything that would stop it from being pulled out, nor would there be anything to keep the air from entering. I was wanting to use Plastimake, but I didn't feel like working with it. I looked around for some relatively thick plastic that I could use, and eventually came upon some picks for bass guitar, which I decided would be the best to use, as it would be the most time-efficient to modify. I drilled a hole, cut a slit to the hole, and made a couple more cuts to make a right-angle. While it's not entirely perfect, it was good enough.

Stopper orientation, and as prototyped.

The fan was a bit annoying because the closest hole saw was slightly larger in comparison to the fan, but I used some thin plastic from a blister pack to make a shim to minimise the air leakage. I think I used some leftover metric screws to mount the fan to the box, and the screw was much longer than needed, but I decided to leave it, as I didn't want to spend forever and a half cutting it down with the saw.

I used some small washers between the screwhead and fan, as well as between the nylon locknut and the box. I didn't really need the one between the screw head and the fan, but since the head was kinda large, I wanted the pressure a bit more even (or maybe something else... I can't really remember). I probably didn't need the washer between the nylon locknut and the box ether, but the fact that I had to drill the hole for the exhaust larger than I wanted made me a bit weary.

Inside and outside of mounted fan.

With that finished, I played around with running the cable in the box, finally finding a good path that wouldn't become a problem, but left little slack.

Not sure what caused the bottom edge to be blurry in some of these shots.

I then mounted the Banana Pi, plugged the fan in, and plugged the power in to test the fan. The connector I used is a 3-pin connector and the wire ties the two 5VDC pins together; the wires were taken from a "salvaged" IEEE 1394 (A.K.A. Firewire) header cable, and I didn't feel like chopping off the extra connector. I found the fan to be a lot noisier than I remember it being, and while it did confuse me a bit, I didn't really care that much.

Banana Pi with power (and without a micro SD card) and spinning fan.

I then moved onto figuring out the location for the hard drive on the lid, and at first, I was going to mount it directly above the Banana Pi, but the SATA cable made that idea more awkward than I wanted it to be. I then mounted it longitudinally along the length of the lid, keeping the hard drive as far away from the fan as possible.

Red marks was where I originally wanted the hard drive to be.

Once I put the stand-offs on the hard drive and had the hard drive mounted to the lid, I plugged the SATA cable in on both sides.

Just about finished.

Once the lid was fastened, I connected everything and set it up a bit before moving it to its final location. Something happened between power down and powering it back up after the move, and so I had to re-image the micro SD card and get everything set back up. But once that was done, I had a nice, easily-mountable file server.

The screws ended up spacing the box away from the interior side of the shelf it sits on, so it has plenty of space for the exhaust. Unintentionally genius.

I think it was earlier this year I updated it, and after rebooting, it wouldn't boot into openSUSE Tumbleweed properly. I diagnosed it a bit before taking the micro SD card to my room to grab the vsftpd.conf file (and I think fstab as well) before re-imaging it with the latest image. Luckily it only took a couple hours to get it back up and running, so it wasn't a horrible time loss. Luckily with the Banana Pi side of the 2(DrivePi), I didn't reboot, so the update that broke the CFS wasn't applied.

SSD from 10 Micro SD Cards

The article I read is: This Brando Adapter Turns Ten microSD Cards into a SATA SSD (which appeared as "Memory Card Hard Drives" when I viewed it on my phone).

 It's not really a new concept (there's CF to IDE adaptor cards floating around the net), but I was just surprised to see it come up.

While it's not the most cost-efficient way to make an SSD, it does give micro SD cards some use if you happen to have a ton laying around.

While it'd be nice to have, considering it could (probably) make a 5TB SSD, I feel like it probably wouldn't be worth my money, since I don't have extra micro SD cards laying around.

Ribbon Cable Tester

I can't  remember if this was the first PCB I designed, but it was definitely the first one that I had made. At work, there's a couple 10-pin (5 pins by 2 rows) IDC connectors that we use, one of which I can access the crimp terminals from the lid, and the other where the lid provides no access. Every so often, there'd be a short between the wires, which is caused from a bad crimp.

The first-mentioned style (let's call this "TE-styled" based from the manufacturer's abbreviated name) I can easily check for shorts with a multimeter after crimping the cable(s), but the second-mentioned style ("Kobiconn-styled") I have to insert a header far enough into the connector to make contact for use the multimeter. While I could insert it all the way, it makes it that much harder to remove once finished.

So I had thought of making something that would it make it much quicker and easier to check for shorts for the Kobiconn-styled connectors, and there's a bag of red/green LEDs that aren't being used for anything, so I grabbed what I needed for the project along with an unused LM317M.

It took a bit to design the board, but once I was done and checked it a couple times, I sent the design out to OSH Park. It took a bit of time, but once I received the PCBs, I was a bit awestruck - mainly from just seeing something that I designed look so professional.

Standard order of 3 boards, top of the board, and the bottom.

I soldered the voltage regulator on first, then the resistors, and then the LEDs before the 10-pin header (which was actually 16-pin, but I trimmed it down). I didn't take into account of the minimum length of the resistor with bent legs, so I had them close to the board on one side and angled upward on the opposite side.

The completed board with test cable attached.

I also had gotten a case and drilled the necessary holes to mount the board, but wanted to leave the final assembly for when I was at work, considering the voltage regulator is ESD sensitive. I then tested the board to make sure everything worked just right, and the green side of the LED was much brighter than I expected - flooding the nearby LEDs.

Power on, pins 1 and 2 shorted, pins 1 and 6 shorted, and all pins shorted.

When designing, I realised that I used a bad reference, which caused me to mis-mark the top-left pin as pin 1 and the bottom-right pin as pin 10. It was the last thing I fixed before sending it out. While I could have fixed the LEDs to correspond correctly, I didn't feel like taking the time to.

Not long after I completed the test, I realised that there were some 3mm LEDs at work as well, and in quite a large quantity. I wasn't too happy with myself, considering I had just spent about 15 USD for the test board, but I was determined to make it better.

The next set of boards.

If you're paying attention, you'll notice that "R3" is missing. I had omitted it because I figured that I would just lower the voltage appropriately and the power LED would light without needing a resistor. I should have given another day before sending the design out, considering I would've caught the mistake.

When testing this version of the board, none of the LEDs (beside the power LED) lit up, and I was confused, trying whatever I could to diagnose the problem. When I was about to give up, I saw a very quick flash and was quite confused, trying a few thing before shorting the legs of the LED, which is when I realised my mistake - the forward voltage of the LED is 2 volts, which is what I had the regulator output.

No other pictures for this version...

I was a bit stressed, now that I've spent another 8 USD in addition to the previous 15. I think I played with the adjustable voltage regulator unit that I made and found that I couldn't make 4 volts from 5.2, so I looked at all the adaptors that I had and coming across the adaptor from the Ikea lamp. I measured the output voltage, and it was just barely over 4 volts (4.02), which I figured would be more than enough, so I went back to my computer to design another revision.

Since the supplied voltage would be exactly what was needed, I only needed one resistor for the power LED, which helped make the board that much smaller. I decided to get rid of the ground pad that I had with the previous revision, since there wasn't going to be anything ESD sensitive on the board. When I received the boards, I set one on the soldering station, and the other two in the pile of tools and stuff next to my benchtop power supply.

It sat for a while, since the company had just moved buildings and I wasn't entirely operational yet (mainly the fact that I didn't have a need to make any ribbon cables). When I was doing the Windows 10 upgrade on Melty, I was bored and decided to solder the parts and then work on whatever I could. I forgot to take a picture of the boards themselves, but it's not horribly different from the previous version.

Parts soldered.

For testing, I didn't feel like messing with the cables because the cable from the adaptor wasn't very long (maybe about 15cm at most?), so I just clipped it together with some alligator clips to my "testing" cable (it's a cable that normally "connects" to my benchtop power supply and is inserted into a couple breadboard holes), stuck a couple of the legs into the appropriate holes, and carefully fed the legs through the power holes of the PCB.

Not entirely the best idea, but I didn't care too much.

After plugging in the cable to the adaptor, the power LED lit up, which was nice to see, but didn't mean anything at all to me. Before I was actually able to properly test it, the ends of the test cable had a mind of its own and wanted to short themselves while I tried to set it up. I tested pins 1 and 2 as usual, and the tested all the pins which gave a good result, as all test LEDs were the same brightness.

Pin 1 and 2 short test, and all pins short test (camera app I use has a weird glitch that crops the image weird when viewing right after taking).

I was quite pleased that I didn't muck up as badly this time, and proceeded to drill the new mounting holes in the case, as well as the holes for the on-off switch and the hole for the cable. I took the parts to work and did the final assembly not long after.

Completed unit, and switch in the on position.

I was going to cover the other holes with electrical tape, but I forgot and didn't care after the board was mounted to the case. I also realised that I mounted the switch backwards (I wanted on to be toward the board), but considering I used the anti-torque washer, I didn't care to have extra holes.

After 30 USD, I think I learned to be entirely certain well enough.