All posts by chrisherman

Sharp PC-G850 Serial over WiFi Module

3D Printing, Arduino, Retro Computing, Uncategorized 1 Comment

YAEP (Yet Another ESP Powered Project): An ESP8266-12 powered WiFi module for the Sharp Pocket Computer via the 11-pin connector connects wireless to PCs for transfer of programs and data. The ESP8266 connects to your home WiFi or acts as an AP for initial configuration. The Serial port of the G850 becomes accessible via TCP on port 23. You can use telnet or netcat (nc) for simple direct transfers to/from the PC or use socat to create a virtual com port. The module supports 9600baud and shortens CTS/RTS and pulls these signals up to +5V, so you need to use XON for flow control. Please note: The G850 uses inverted serial protocol logic levels (i.e. logical “high” is represented by a “low” (0V) TTL level, logical “low” is represented by a 5V TTL level. The ESP8266 uses the SoftSerial library on GPIO 4 and 5, which supports inverted logic levelsRaw TCP is implemented without encryption on port 23. You can connect via telnet to receive or send data or programs but everyone on the same network can read the transferred data in clear textThe module does only support serial port communication (i.e. it does not emulate the CE-126 synchronous communication for print and cassette tape commands)In the TEXT/Sio/Format menu enable 9600 baud, 8N1 and no flow-control. End-of-file “1A” allows the G850 to stop listening when receiving a file. You can still send files without the end-marker, but need to interrupt the “load” command by pressing “ON/BREAK”. The received text will be in the editor. Sleep…

Read More »

Vertical Pinball Machine

Uncategorized Leave a comment

Vertical Pinball Machine Parts: Windows 10Pinball FX3 (Steam)34” QHD Ultra Wide 1440p Monitor (Samsung LS34J550WQUXEN)7”Screen Display 1024*600 LCD MonitorRadeon RX590Dell Optiplex 3020 (8GB RAM, 3.2GHz i5-4570Inductive Plunger (allows trick shots)2x45W Stereo, 68W SubwooferOak case ArchitectureThe vertical Pinball machine was build on a Windows 10, Optiplex 3020 (i5) with 8GB RAM and a 16GB Radeon RX 590 (8 GB GDDR5). The Dell Optiplex shows a BIOS error when the front cover is not connected (and I threw it away before realizing I should have kept the cable). So I added an additional Arduino that emulates a keyboard and sends an “F2” keystroke 5 seconds after power-up. I am particular proud of the inductive plunger, which allows skill shots without use of a linear potentiometer (no wear!). You can Google “Arduino Inductance LM339” and will find good description of how to do it. Schematics and board can be found in the resource section. One problem remains unsolved: I need an external keyboard to shutdown windows. I did not want to mess with any software that maps keystrokes, so at the end of the gaming night, I pull out a little wireless keyboard and shutdown Windows. No enough of an inconvenience to warrant drilling another hole in the cabinet. CabinetI ordered a kitchen worktop (2m x 0.9m x 2cm), cut it into 12cm wide boards of 2cm thicknes and various lengths, halved the thickness to about 8mm (thereby doubling the number of boards), glued the boards together to form 8mm thick sheets and cut the sides of the…

Read More »

DGT-3000 Raspberry Pi Connector

Chess 1 Comment

PicoChess is a software developed by Jean-Francois Romang that brings several chess engines to a DGT board and allow full control via the second queen (i.e. no cpmputer required!. It works with a Raspberry Pi and a DGT-3000 chess clock. DGT offers an all-in-one solution (DGT-3000 with a Raspi) for £280. The DGT-3000 alone sells £50, so quite an up-mark for a £28 Pi! Based on the work others have done, I developed a board that allows you to connect a Raspberry Pi to the DGT-3000 without too much hassle. You need a soldering iron for the power cable (from the Pi to the DGT-3000). The solution consists of the following components: A DGT-3000 Raspberry Pi (a Raspi 3 will work best with the PicoChess engines, though a Zero W cor an older Pi can be used as well) The connector cable (Pi-Hat with molex and power connector for the clock) a 5-pin Molex connector cable A Case that serves as a base for the clock and houses the Pi and the connector board You remove the small board that holds the 3.5mm connector and instead the board will be connected directly to the RasPi via USB (I added a magnetic USB-C connector to easily hook up the board and the RasPi. Just to clarify: After this conversion, you will no longer have the 3.5mm connector (and a little hole on the side of your DGt-3000). Layout of the molex connector: This is the layout of the board that connects the RasPi with the mainboard of the DGT-3000.…

Read More »

Micron 3DP Metal Extruder

3D Printing Leave a comment

Adding an all-metal extruder to a Prusa i3. The Wade extruder on my i3 started to slip and not enough filament was extruded, so the prints started to look flakier and flakier. I checked the extruder, refurbished the hobbled bolt, but the problem came quickly back. Only once I increased temperature to over 230C (for PLA!) it completed prints – of course the result looked like roasted marshmallows. So I ordered a new J-Head hot end (0.4mm) and a new all-metal extruder. Price on ebay was $175 plus $20 shipping. Quite steep, but I have no regrets! Build quality is excellent and the Nema 11 stepper has plenty of power thanks to the gearbox (at first, I used same driver setting as for my Wade extruder’s Nema 17 and subsequently the stepper would become very hot. Adjusting the reference voltage of the driver board to 0.45V solved the problem). I had to print a new mount to fit the extruder. That was a bit of a challenge, given I own only one 3D printer, and that one was broken. I managed to get one decent print: enough to mount hold the new extruder in place. Once I had the printer re-adjusted (M92 X80.00 Y80.00 Z4000.00 E1333.33), the first task was to print a better mount. Result is attached below.   Not sure if it’s the new extruder or the recalibration of the machine (incl. resetting x and z end stops), but now I am finally able to print straight onto glass (using a watered down…

Read More »

3D printed Nema 23 mount

CNC Parts Leave a comment

Print you own Nema 23 motor mount. A low cost alternative to aluminium mounts and more accurate than most wooden constructions. Nema motor mounts are usually quite expensive. The quality of the mount does very little to a CNC machine’s accuracy. So I decided to print one. It raises the motor about 2mm above ground. My motors fit snug into the mount hole. The mount is relatively sturdy. I had a bit trouble with warping, since my heated bed didn’t work properly. Thickness of the base can be increased to improve rigidness. For the particular machine I built, 2 mm was al I could afford. Nema23-Mount.skp Nema23Mount.stl  

Read More »