Ah, that did it. I had spent ages wading through pages offering advice before asking, but failed to find that. Obviously used the wrong search terms. Many thanks.

My (headless) Pi has a tiny 5" composite monitor, just for checking status. Config.txt includes: sdtv_mode=2 sdtv_aspect=1 but I want the monitor mostly OFF, and I can turn it off perfectly with: /opt/vc/bin/tvservice -o BUT although /opt/vc/bin/tvservice -c "PAL 4:3" ...turns the screen lights back...

All very helpful, thanks.

Is there a way of identifying the current setting of a pin set to Write mode? In other words, if I've got a pin set ON, lighting up a led, can I discover that from a script?

Well, for the record, below is my very rough bash script that: shows one temperature probe; switches on/off up to 7 relay circuits in a hard-coded sequence (using Gordon Henderson's WiringPi pin addresses); and provides a neat colour-coded status display on the terminal. #!/bin/bash NONE='\033[00m' ...

OK, let me lay out where I am. Or at least where the plan says I am... I'm installing a heating system, controlled by the Pi. I have DS18B20 temperature sensors connected to the Pi's GPIO4 (WiringPi 7). That pin is hardwired for the DS18B20, but you can daisy chain several (they are each addressable...

I haven't actually done this yet, but if you're getting a bandwagon going I'd like to join it. I've got a prototype heating controller working well via a bash script, but now want to make it a bit more grown up by porting it to FP. (And I mean FP, not Lazarus; it won't need any window-based front en...