Temperature module instructions
===============================
Getting an digital value into your BBC to represent the temperature of some
physical object is made simplicity itself by attaching a ready made board to
your beeb. Before, the alternative approach would be to use the analogue port 
to read from a thermistor of similar device - but which would be hard to 
calibrate.

This module allows temperature data to be shifted into the BBC as a background
task, while you continue to use the machine for another purpose. This could be
of use in (for example) a shop, where the BBC was used for stock taking while
also monitoring (and saving...) the temperature of chillers for hygene reasons.
Or monitoring the temperature of your greenhouse while typing a letter to your
aunt!

PARTS...
The circuit diagram shows electrically how to assemble the unit, requiring the 
following parts:
1x  Ready built module (Maplin order code: FE33L)
9x  ZTX300 NPN switching transistors
9x  10k pull up resistors
9x  1.2k base resistors

In addition, it may be useful to have a handful of pins, a user port plug and
a couple of feet of ribbon cable.

BENEFITS...
*Software selectable sample rate, mode, and hi/lo point
*Large LCD display for operation without the computer
*Runs off a single AA battery
*Choice of Celcius or Fahrenheit
*Seperate 'hi alarm point reached' and 'lo alarm point reached' pins

BUILD...
1.Join from the premade module to your board with a short length of 14 way
  ribbon cable, noting which wire is ground.
2.Attach the resistors and transistors from the output from the BBC user port
  to the control lines on the module. The 'REM' statements at the start of the
  software and the hints section below tell you which is which. Note PB7 was
  not needed.
3.Do the same again in the opposite manner for the data and clock inputs from
  the temperature module back into the BBC's interrupt lines, CB1 and CB2.
4.Ensure that both 0v lines on the BBC and temperature module are joined 
  together.

HINTS...
*You might want to add a three small (1.5v) piezo buzzers to the alarm point
 pins, pin 6, 7, and 15. Otherwise, just leave them unconnected. Ground is 
 pin 1.
*The software can easily be modified if you made a mistake wiring up the pins
 though I suggest: PB0 = show lo point      => module pin 13
                   PB1 = show hi point      => module pin 12
                   PB2 = celcius/fahrenheit => module pin 14
                   PB3 = sample rate select => module pin 5
                   PB4 = set hours          => module pin 2
                   PB5 = set mins           => module pin 3
                   PB6 = clock/temperature  => module pin 11
                   CB1 = data               => module pin 9
                   CB2 = data load clock    => module pin 10

FROM...
Robert Sprowson.
Happy soldering!