A short, if belated update to how the maker community is helping tackle to Coronavirus. Again these are just some links that I spotted during normal web browsing.
It’s not very often that I comment on current events but the Coronavirus or COVID-19 or SARS-Cor-19 is too big a world event not to have some views about. As a maker and also a professional (cough) engineer I’ve been intrigued by the maker community’s response to these events. We’ve seen makers use their faculties to make face masks and face shields using 3D printers, sewing machines etc. not for themselves but for their wider local community and their local health professionals to help protect others against the spread of the virus.
There are many makers and maker companies that have been very proactive in this, just naming a few, companies like Adafruit have lead the way and their blog has many posts. Other useful sites I found are:
Maker communities such as Hackaday and Instructables also have many useful posts. As well as the blog entries themselves, the various comment section are full of very interesting points made by reverent professionals, as well as interesting details and suggestions by other interested parties. Below is a short list of some of the other links found:
In addition, many universities and other groups have also proposed alternative equipment designs and builds:
Scientic and Medical Journals and Articlas:
Standards and Regulation
And finally, its also the call to arms by many governments to their countries biggest or best industrial companies to help eleaviate their medical equipment shortages. The mainstream media have been quick to jump on these stories of Formula 1 teams, big defence and big consumer companies banding together to rapidily design and manufacture the much needed medical equipments. Others have asked why their countries are not doing the same or enacting war time or emergency powers to allow manufactures to quickly add their manufacturing might to the effort.
I recently started doing a small fun project with a RPi and a BT enable remote controlled car. (Dagu Racer 1) when I hit some problems with writing Python code to connect to the RPi’s BT.
After some web browsing and a bit of trial and error I found the following application updates and library installs got things working.
sudo apt-get update
sudo apt-get install bluetooth bluez libbluetooth-dev
sudo python3 -m pip install pybluez
For the Python code
# Bluetooth stuff
bd_addr = “20:13:05:30:01:14”
port = 1
sock = bluetooth.BluetoothSocket( bluetooth.RFCOMM )
# 0x1X for straight forward and 0x11 for very slow to 0x1F for fastest
Last year Parallax released their latest multicore processor, the Propeller2 or P2X8C4M64P to give it, its full name. It’s been a very long time coming and after a few setbacks it is finally here. It’s specs are very good, featuring 8x 32-bit cores (or cogs as Parallax likes to call them), 512K RAM and 64 GPIO with SmartPin features.
I got my P2 evaluation system (ES) board a few weeks back and designed a couple of P2 ES prototyping wings to go with it.
The first prototyping wing (on the right) is a classic proto board with I/O from two GPIO ports. The other prototyping wing is a breadboard design for faster circuit build and test and features a 3x LED’s and 2x switches
I’ve got a few spare PCB’s which I’ll put on my Tindie store.
This week saw the arrival of another big box of PCB’s. A lot of PCB’s. Some old but many new.
Also in the box where some new board designs. No new RC2014 PCB’s this time but some boards for the ZX Spectrum and Commodore 64 computers. I’ll share more details of these in the coming days and weeks.
Time to break out the soldering iron 🙂
Here’s my Tindies store.
When the ZX Spectrum came out in 1982 the options for data storage on home computers were very limited. You usually had the choice of audio cassette tape or floppy disk. The ZX Spectrum initially came with audio cassette storage via an external cassette player/recorder. Sinclair Research would develop a variation of tape storage in their microdrive system via their Interface 1 add-on and it was only very much later that floppy disk storage would appear as a add-on option (i.e. DISCiPLE drive) or as a official computer model (the ZX Spectrum +3)
Now, lets fast forward to the present. Audio tape cassettes and floppy disks are very much a thing of the past and getting new blank tapes or disks is difficult to almost impossible.
However all is not lost as the retro community has been very busy in the intervening years and has come up with many alternatives to tape and disk storage. These alternatives are usually based on either Compact Flash or SD-Card. Below is a short list of some DIY projects:
“Everdrive”/DivMMC for Spectrum list
View at Medium.com
SD-Card interface round-up
ZXMMC+ (sd-card access, IF-1 – RS-232 and Network), 1MB ram/rom, Kempston joystick
ZXcard DIY SD/MMC interface
maxduino – Unified firmware for tzxduino and casduino
Tapuino-Reloaded – A reworked smd version of the Tapuino Mini Pro.
TzxDuino-Reloaded – A reloaded version of the TzxDuino
TZXDuino Arduino based TZX
Now I’m back on my retro computers I’ve put together this quick guide for those looking to diagnose and repair ZX Spectrum computers.
Schematics and Service Manuals:
Having a set of schematics or even better a full service manual is the good thing to have before starting any repair. Fortunately for us, full schematics and service manuals for the all ZX Spectrum models are available on the web. I have my Speccy schematics printed out on the biggest paper size I’ve got access to, namely A3. The service manuals are a great place to start when looking to diagnose a fault.
Schematics and Service manuals can be found at:
IC Data sheets
Diagnostic Software Tools:
Happily the ZX Spectrum has quite a few diagnostic software tools to help the would be fixer in his fault diagnostics. Most of these are based on external ROM device which avoids the need to have a fully working Speccy or the problem of loading diagnostic software from tape.
Here’s a few ROM based diagnostic tools
Brendan Alford on github has “ZX Diagnostic”
Paul Farrow of fruitcake has the following ROM tools: 128K RAM Tester & ROM Tester
he also has the official Sinclair Test ROM as well
Phil Ruston of Retroleum has the following “ZX Spectrum Diagnostic ROM”
Screw Drivers: Philips and flat blade
IC extraction tool
Power Supply (Adjustable/current limited)
Diagnostic software tools (see above)
TV Monitor/Screen (or car reversing monitor for composite video)
Anti static wrist or foot strap
IPA Wipes (no not the beer) – Isopropyl alcohol to clean edge connectors and contacts
Good web sites:
If the your own best efforts have not yet found the problem then there several good web sites that share their repair achievements where you can search. I like the following sites:
Dave Currah of Tynemouth Software
If you’re still no wiser, then try asking on one of the various Retro Computing Forums or general electronic forums in their repair section if they have one.
Remember to share as much information about the Speccy model, what it is not doing and what you have tried so far. Avoid simple statements like “Speccy not working please help”. It goes without saying that following the forums etiquette for posting will usually get you a more productive and polite response.
World of Spectrum forums
These are more general forums: