Psion 2 Interface

-

This is my first foray into interfacing to the Psion 2 organiser using the circuits and machine code routines provided on Org2.

So far I just have an 8-bit output port working (using a 74LS374) and to test this I rigged it up to my trusty serial LED display. This display was salvaged from my first ever CD player (bought in Dixon's in 1988) after it finally died. It's based on an M5450 serial LED driver chip and is easy to communicate with over 2 wires (clock and data).

The Psion 2 archive...

Eventually I want to get this working with my 'classic' Lego robotics (4.5 volt motors, very home brew) and finally get the Lego arm working properly.

Popular posts from this blog

Electronics Upcycling

-
Image
ELECTRONICS UPCYCLING FAQ CHECK OUT THE OTHER POSTS ON THIS BLOG FOR DETAILS ON REPAIRS AND UPGRADES GOING BACK OVER 10 YEARS - What's the story? I've been tinkering with circuits for over 40 years and have an MSc in microelectronics, and a few years ago realised I could combine this with saving the planet. Basically I'm Greta Thunberg with a soldering iron. - Saving the planet? Well every electronic item kept out of landfill reduces the amounts of dangerous 'forever chemicals', getting released into the environment. By repairing items or stripping out most of the reusable parts this reduces what ends up in landfill and ensures the components go into the correct recycling bins, such as hard plastic cases. - Don't the council do that? Up to a point, but information has emerged about huge amounts of European electronic waste being shipped to Africa and Asia where it continues to damage the environment and people's health, especially the women paid ...
Read more

Powered USB Hub - £2

-
Image
 I bought a couple of these little USB 2.0 hubs for £1 each in PoundWorld intending to adapt them to be powered hubs for use with RaspberryPi computers.  Alan here ( http://pihub.blogspot.co.uk/2012/06/raspberry-pi-power-supply-and-powered.html ) beat me to it, but I wanted to give it a go with a flying power socket.  As usual, heat-shrink sleeve comes in to save the day. I didn't like the original USB lead and plug so I bought a USB-to-Micro USB cable (again for £1) and cut it in half.  One end goes to power the RPi and the other is the input USB. The input USB has only 3 connections made, the red power wire is cut short and ignored.  I did connect the ground (GND) wire though because the purist in me doesn't like the idea of floating grounds (blame my MSc).   The output for power to the RPi via the micro USB plug only has the GND and +5v connections made and the other 2 signal lines were chopped short and ignored. The power input was made ...
Read more

Update on the touch monitor

-
This is tantalising... I found some data on driver chips used on these low-cost monitors and some of them have an I2C connection for sending pixel data directly to the screen. This may be to allow text or graphics overlay. Anyway the chip on my 7" screens is an AR05C-LF and there are millions of these in stock in the far east, but I can't so far find a data sheet for this chip or its sibling the AR05CA-LF. Being able to send digital pixel data via I2C directly to the screen would be, well, brilliant.
Read more