In article ,
Axel Berger   wrote:

>This leads to two questions: What programming language should I use? I
>haven't done any real programming in ages and the languages I used to
>know are obsolete. I have done (or rather used) a simple test routine
>for my solenoid output card in python, which seems to be the accepted
>standard for the pi, but I don't like it. Are there any better
>alternatives (except c, which I hate)?

The Pi, being a Linux PC runs 100's of different programming
languages. Python is just 2 of them.

Try BASIC?

  sudo apt-get install rtb

and off you go. It supports most of the gpio natively.

(With the disclaimer that I wrote RTB :-)

You can also test simple stuff using the gpio command - and then use
that to write shell scripts too - if you want to code in bash or another
shell...

>The second problem is hardware. The ducts leading to my current
>thermostats are strictly a star configuration, so one wire is not the
>obvious choice. What ohter kinds of sensors are there and how can I
>connect at least 8 to the Pi? Part of the GPIO, 8 output pins, is
>already taken by the solenoid card.

You can star wire 1-wire devices, but it's not the best way, however,
depending on the distance, you can pseudo-star them - ie. wire from the
master to the first sensor, then back to the master, but not connected
to anything, then off to the next sensor, and so on. It's just one big
bus and you can use 4-pair cat-5 cable for the connection to each one,
so 2 pairs using 3 wires for the "out" leg and another wire (or pair tied
together) for the back leg to the next sensor. You'll want to use active
power for this rather than parasite power, so you'll need a resistor
and power & gnd. at the Pi end.

Gordon

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