A while ago I purchased an RGBtoHDMI adapter for my Acorn BBC-B, BBC Master and Electron computers.
The RGBtoHDMI adapter is an amazing Open Source project; it samples the “old” video output of your computer and converts it into super crisp HDMI output for your modern TV or monitor.
The “12-bit” board came with an adapter for the Acorn computer RGB output, as well as a professionally produced case to hold the adapter.
Assembling the hardware
I used a Raspberry Pi Zero v1.3. After soldering on the header pins, I inserted it into the case. The MicroSD card will be installed later.
Next, connect the RGB adapter cable to the RGBtoHDMI board:
And install the RGBtoHDMI board on top of the Pi Zero:
Installing the software
The RGBtoHDMI software runs on “bare metal”, so there is no need for an operating system.
Unpack the ZIP-file and copy all files to a freshly FAT32-formatted MicroSD card. Install the card into the RGBtoHDMI adapter - and you’re done.
Using the adapter
NOTE: The RGBtoHDMI adapter is powered from the RGB connector on your computer - do not connect a USB power supply!
Connect the RGB connector to the BBC, connect the RGBtoHDMI adapter to your monitor (using a mini-HDMI to HDMI cable). Switch your monitor to HDMI input, and power on your Acorn Electron or BBC (Master). The adapter should power up (green LEDs), and after a brief wait you should see a menu overlay.
I used automatic calibration, and the result was great. Super crisp, pixel-perfect HDMI output from my BBC micro. Here’s a photo of the LCD monitor: