PICAXE PROJECTS (Two Probe Digital Thermometer )

Steve S

Got my Two Probe Digital Thermometer running but not as I hoped for.
The FT probe works perfect on 1.5m cable but 5m shielded cable I wanted to use is a no go.

It shows temp. on Turn On, Actual Temp. and Min/Max Temperatures in deg.Celsius,
no decimals, not bellow freezing (0)deg.
Would need bit more of clever programming.
Could be done, les than half of available memory is used.

The probes, DS18B20 are insulated in two layers of shrink sleeve.
Worked well on the test run but will pot the FT probe into something more secure
to prevent moisture seeping in.

The first DC socket is for 12VDC, the second is for 4 x 1.2V Ni-MH battery pack or similar to 5VDC.
Only one power source is needed.

Code:

;********************************************************************
; Project by Steve S 
; Date: 28/05/'08
; Re:29-05-2008,#2westaust55
;
; For PICAXE: 08M
; Clockfrequency: 4MHz
;
; File saved as:TEMP-CURRENT-MIN-MAX-2X-v2
; Version:v2
; Bytes used:112/256
;
;********************************************************************
; Program function: Measure and display temp at reset, current, minimum 
;                   and maximum temperatures until reset.
;
;====================================================================
; Pin assignement-Input: I3 - reset
;                        I/01 - DS18B20-air
;                        I/O4 - DS18B20-water 
; 
;                Output: I/O2 - serial LCD
;                                     
;====================================================================
; Init routine:   
                Let Dirs = %00000100   'Pin2 Output
                Let Pins = %00000000   'output 2 low
;
;====================================================================
; Main program 
         
  Main:  pause 500
         serout 2,T2400, ("?G216")
         serout 2,T2400, ("?c0")
         
         
         pause 100

S_read: readtemp 1,b0         'temperature on start/reset
      
        readtemp 4,b4 
        
               b2= 127             'minimum temp. var. (b2)
               b3= 0               'maximum temp. var. (b3)
                                    
               b6= 127             'minimum temp. var. (b6)
               b7= 0               'maximum temp. var. (b7)

C_read: if pin3=1 then goto S_read
           
        readtemp 1,b1             'current temperature
        readtemp 4,b5         
        
        if b1<b2 then 
           b2=b1                  ' new minimum
        elseif  b1>b3 then 
           b3=b1                  ' new maximum
        endif                           
        
                              
                
        if b5<b6 then 
           b6=b5                   ' new minimum
        elseif  b5>b7 then 
           b7=b5                   ' new maximum
        endif
         
       
        serout 2, T2400,("?y0?x00AIR:?i",#b0,"?i",#b1,"?i",#b2,"/",#b3)
        
                  
        serout 2, T2400,("?y1?x00F/T:?i",#b4,"?i",#b5,"?i",#b6,"/",#b7)
        pause 300
         
         
        goto C_read
;
;====================================================================== 

; NOTE: Serial LCD module instruction set from Oatley differs to the Rev- Ed’s AXE033

; http://secure.oatleyelectronics.com//product_info.php?cPath=81&products_id=269& osCsid=c635a14e8058999b2310ddc4997fb6b3

; AXE033- http://www.microzed.com.au/displays.htm 

 

Steve S

And inside of he box.

Outbackozzie

Steve, what does something like that cost to build, and can it be monitored via a PC, to a webpage?

I spend a fortnight away from town at a time, so I would like to be able to keep a better eye on FT temps.

EllKayBee

Compact and well laid out Steve - nicely done :thumbup:

Hex

Yep, the veroboard circuit looks very tidy.
Building your own stuff is very rewarding..especially when it works first time :wink:

Steve S

OBO, except for programming, I didn’t use a PC to monitor o control anything as yet, so I wouldn’t know how to go about it. Only hobbyist, not expert in this field.

Unless you do have already a web server able to monitor and control your AP sys.
to monitor temperature alone wouldn’t be worth it.

About two years ago Silicon Chip run a tutorial on a very basic Pic based server with 8 pins that could be configured individually as input, output or special function.

It could read the DS18B20 Digital Thermometer directly.
Or could use a Picaxe to process the data and send them to the servers shared memory to be read and displayed.
So it would depend on you servers capabilities.

DS18B20 is AU$ 9.95 each
The small 08M Picaxe I used is AU$ 6.10, all from Altronics

The serial LCD wouldn’t be needed, that’s the costliest part in my gadget.

Steve S

EllKayBee wrote:

Compact and well laid out Steve - nicely done :thumbup:

HEX wrote:

Yep, the veroboard circuit looks very tidy.

Had a full version of EAGLE cad I inherited

, but it became obsolete and the new demo I am using now is rather limited in board size
so I have to try to accommodate the components as best as possible or divide bigger projects into smaller daughterboards.

Quote:

Building your own stuff is very rewarding..especially when it works first time

Usually try it first on a protoboard before hardwiring it, so it should.

steve

fantastic work.

are the DS-18B20 part of the dallas "1-wire" (i-button) range?

ifso then there may be a web interface software on their website. in which case you could use the w-ire interface (i still have a few of them i think) to directly link the sensors to the PC.

They even have a SDK so you can make your own pc programs i think. has been about 5 years since i played with the DS1920's

Hex

Breadboard is very useful, i usually just goferit :wink:

A webcam might be an option for remote monitoring on the cheap.

b2barker

Awesome work Steve S.

Quote:

Steve, what does something like that cost to build, and can it be monitored via a PC, to a webpage?

For PC monitoring you could use something like the Link45 or LinkTH along with the same sensor Steve is using. That would give you up to 300m of cable from PC to sensor(s). Then a free serial port logger can store the data in text files. So for AUS$80 and a Ethernet cable long enough for PC to tank you are logging to file. To get it on the web maybe something like Fling which would just FTP your logger file to your web page.

Steve S

Yes Steve, it is one of the Dallas parts,
Spent some time on that website, going through the Ap. Notes
trying to find something on those devices cabling.
Lot of staff there, don’t remember it all.

Quote:

Awesome work Steve S

for that little gadget, this coming from a pro, B2B,
how many Brownies frm you will I get those ones:

Ten lines Sequencing, Moisture Sensing Watering Sys. decommissioned because of the water restriction,
some of the daughter boards already cannibalized. Boxed in an old Amstrad case.

X-tal controlled Pulse Generator/Counter, unused since I got a selfranging DMM with C and Frequency capab.
and a cheap Velleman LCD Scope over two years ago.
All on stripboard. Had no heart to strip it for spares yet.

Thanks for those tips B2B

scottt

Steve S - The vero board King !
Neat work, well done !

Bridgette

HI
Looked for a place to put this and thought maybe this is a good place, its a link to a website and they have electronic AP projects, dont know the quality of the projects but it looks ok

Bree

http://users.bigpond.net.au/eagle33/elect/elect.htm

Charlie Price

nice work steve

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PICAXE PROJECTS (Two Probe Digital Thermometer )

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