Side projects and fun

DRILLED MOUNTING HOLES AND INSTALLED THE TWO BOARDS ON THE COVER They will hang under the cover when it is closed. I drilled, installed hardware and verified the fit of all the parts. My initial placement of the transformer caused interference with the heat sinks of the power supply - will relocate it slightly tomorrow. GROMMET INSTALLED FOR POWER CORD ENTRY I popped out an opening on the side and installed a nice grommet to protect the power cord as it enters the metal box. I will also add a lug for the ground pin of the power cord to the enclosure.  COSMETIC WORK NEEDED TO STRAIGHTEN EDGES OF THE BOX Taking one side off the box was harder than expected, even with drilling out most of the spot welds. There was a lot of twisting that left the edges wavy and bent. I had to restore it to decent shape before I cover the edge with a plastic mounting plate. 

DISCOVERED INTERESTING FPGA BASED PDP-8 HARDWARE REPLICA This design implements the hardware logic from a PDP-8 inside a single FPGA, something similar to how I recreated an IBM 1130 into a gate for gate cycle accurate replica using an FPGA. It runs on a Cyclone IV FPGA board that is plugged into a host board implementing memory, USB and some I/O connections.  The host board from Land Boards is a  RETRO-EP4CE15 board, which I bought on Tindie. It has a QMTech EP4CE15 FPGA board plugged into it. The bill of materials was easy to source on Mouser other than one voltage regulator chip which was obsolete/unavailable but for which plug compatible replacements exist.  Assembling it brought a minor frustration - the silkscreen on the host board has no indication of orientation for the SRAM and USB chips, nor does the assembly instructions. I had to refer to the schematic and beep out the pads to determine which way to place those chips.  The resolution of the pictures (and...

PLACED EDUC-8 INTO THE FRONT OF THE METAL BOX I need to add plastic to fill a slight gap on the left and right sides of the box between the faceplate and the sheet metal. This will be purely ornamental. In addition I have to place mounting brackets to hold the PCB stack firmly in place. Test fit POWER SUPPLY BOARD, TRANSFORMER AND CROWBAR BOARD WILL FIT They are a tight fit, so I have to drill holes and put in standoffs to hold them in the appropriate locations in side the box. I did find orientations where they could fit correctly. 

A STEROID SHOT ALLOWED ME TO WALK AND DRIVE I was able to drive over to the workshop and do some work finally. Not wanting to overdo things, I only spent an hour today but expect to ramp up over the rest of the week.  3D PRINTED FRONT PLATE FITTED ONTO THE EDUC-8 The cover fit well. I need to find the correct size screws to pass through the two parallel PCBs, the spacers between them and into the front cover. It will then be ready to insert into the metal case. METAL CASE BEING PREPARED I bought a metal electrical box that had the right dimensions. I have to remove one side of the box to slide the EDUC-8 in and secure it leaving the front panel at the proper point. The metal box had spot welds that were quite strong, which required a lot of hacksaw and bending to open. My drill battery was drained otherwise I would have drilled out the rest of the welds and finished the job. 

FRONT COVER PRODUCED BY 3D PRINTING SERVICE COMPANY I had uploaded the design file to Sculpteo, who finished the part and mailed it back to me. It looks great, assuming that the original design file was correct so that this fits the EDUC-8 I built. 

DOCTOR READ MRI AND UPENDED MY BELIEFS Going into the meeting I was expecting that the MRI would show a meniscus that was torn and blocking movement, or perhaps a ligament rupture also blocking knee movement. The solution would be a minor operation to remove the damaged bit and I would be back on my feet.  Instead, the MRI showed that while I did have two torn menisci, there was a whole lot more going on in there. The inside meniscus had multiple tears and 'partial maceration', clearly jammed out so it was not between the femur and tibia at all. The outside meniscus had a simple tear.  However, the inner part of the knee had cartilage missing in segments 2.5 and 3.6 cm long, where one bone was directly rubbing on the other. This was deemed severe osteoarthritis. The other side was better but still work down significantly.  The space under my kneecap showed moderate to severe arthritis, with a lot of bone softening and the patella was not tracking properly. Finally, I have...

SUDDEN KNEE PAIN AND INABILITY TO BEAR WEIGHT A week ago when rising from a chair, I felt a severe pain in my knee. I was not able to straighten the leg more than about 75 to 80% without incurring the pain, but could bear weight when bent. When this didn't ease up within a reasonable time, I visited an emergency room. I was referred to an Orthopedic Surgeon whose office I visited the next day. By midweek the knee was scanned by MRI and an appoint set for Monday (tomorrow) for the surgeon to complete a diagnosis and work out a treatment plan. The preliminary assessment was a mechanical block due to a meniscus tear, but the actual soft tissue damage depends on the reading of the MRI.  CAN'T DRIVE AND NEED MOBILITY DEVICES TO MOVE AROUND I am unable to reliably move my right leg to operate a motor vehicle. The only way I can walk putting weight on the leg is to bend way over into a Chuck Berry like duckwalk so that both knees are at a significant bend. This is not very practical. ...

USED SCULPTEO AS THE FAB FOR 3D PRINT AND LASER CUTTING Sculpteo.com is an online service I had used for prior work, thus this is who I submitted the files to print the front cover and cut the acrylic insert. They contacted me after they did the first cut, because the size of the text characters and line width caused significant burning and discoloration on the acrylic.  Their recommendations were to scale up the text or do other things which require me to take over the design of the panel and update it. Since I was just using the design from Gwyllym Suter directly, which he produced in FreeCad. Not only am I totally unfamiliar with using FreeCad, but the text used a font that he did not include with the files and that I don't recognize. Further, the esthetics of the EDUC-8 depend on the size and placement of the etched text, which would be thrown off if the text were doubled in size.  I am thus trying to recreate the panel in Inkscape and use acceptable line widths and spacin...