[tech] temperature logging
adrian at ucc.gu.uwa.edu.au
Mon Jul 11 10:05:28 WST 2005
amusingly, this is about the kind of thing I was going to build
tomorrow using an AVR. It shouldn't take too much effort to make
an 8 port input/8 port output device. Temperature sensoring is
available, as the AT90S8535/ATMega8535 has 8 ADCs.
Tis up to you all. I think electronic projects are fun. :)
On Sun, Jul 10, 2005, Davyd Madeley wrote:
> I acquired a serial I/O board on loan from work (will have to buy
> them a new one). This board offers 8 bits of digital I/O and two 8
> bit ADCs.
> One of these ADCs is now connected to a thermal sensing
> semiconductor. The board is connected via RS-232 to Centipede, the
> DECserver in the tall rack.
> To read the temperature:
> llogin THERMAL <-- connect to the board over LAT
> rd0 <-- read port 0
> (the decimal representation of a byte will be displayed, close the
> connection - ^] on mussel)
> dc <-- everyone's favourite calculator
> $reading 139 - 0.512 / p
> (prints the temperature in celsius)
> It's only accurate to about 2 deg C according to the appropriate
> datasheets, so the decimal places aren't that important.
> It's currently connected using an Eric, because I couldn't find
> enough appropriate serial to connect it, specifically a DB-9 gender
> bender. It's also connected to a 9V plugpack via a 110V stepdown
> transformer, as I couldn't find a 9V pack designed for Australian
> If we want, it would be very easy to tie the door sensors into this
> thing using some 10k resistors (to stop the inputs floating). It can
> also provide enough current to drive a solid state relay (for the
> door lock) and has another ADC, if we wanted a second temperature
> The machine room is a pleasant 35C at the moment. This has not been
> tested against another thermometer.
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