Shop OBEX P1 Docs P2 Docs Learn Events
If I want 6 separate temp readings do I need 6 separte three pin groups on my b — Parallax Forums

If I want 6 separate temp readings do I need 6 separte three pin groups on my b

technoobtechnoob Posts: 21
edited 2009-02-09 01:43 in BASIC Stamp
·· Good Morning Parallaxians.· 12:06 am

Of course there arent 18 pins available on my bs2.·lol.gif·· My application will eventually use my one and only BS2P40.· I still dont want to use up my pins so quickly.·

Its a synchronous serial question actually.········About wich I know enough to cuase trouble and achieve little.····(Synchronus Cereal with toasted ICs and a glass of milk)

Im on a vertical leaning curve and my ears are poppin.·· wheee!··· any way

I need to take 6 temerature measurements with data not just a thermocouple, thermometer, variable resitance thing.··· Actual temp Measurments like the DS1620 generates, along with·the thermostate ouputs as well.· (I plan on sending the 12· thermostat pins on the 6 DS1620s to cascaded shift· registers.)

When it comes to this device (DS1620)· I noted that it isnt "addressable".· If I want 6 differnet locations to be measured I need 6 different DS1620s.··· Since I need 6, I think I will need 18 pins to communicate with them.··· Since pins are like gold I dont want to waste them.

IMPORTANT NOTE:· Ima noob.· I just finished "Stamp Works" and have a BS Pro Development Board.· Dont let that fool you.·· Ima still a Noob.· My goals are a little high for my extreme noobness but·I will achieve my design objectives.· With a little help from my friends that is.·

Question 1.
········· Would 6, DS1620s require 18 pins?················································································
Question 2.·
········· If yes to above please advise.· Different temp IC maybe?· One that is addressable?

Question 3.
······· Start fresh.··· How should i take·6 differnent temp mesurements that would report the temp and execute the thermostatic functions like the DS1620?.·· Each temp reading would only need to·polled or read avery·2 to·3 seconds or so.· The equipment im measuring is sensitive but I can adjust the high and low temp variables to compensate for increased delays between reads if the suggested temp device allows it.

This beast of a project·may require multiple BS2's.

Thanks guys
Randy C· 'technoob"
This forum rocks.·
·

Comments

  • MSDTechMSDTech Posts: 342
    edited 2009-02-08 23:25
    You should be able to get by with 8 pins.
    One for Data
    One for Clock
    Six for the individual RST lines.
    Just make sure you do not take more than one of the RST lines high at a time or you can have collisions on the data line. There should be a 1k resistor on the data line of each DS1620 in case there is a collision.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-02-08 23:48
    You should consider using 1-wire thermostats from Dallas Semiconductor like the DS1822 or DS1822-PAR. These are inexpensive (less than $2) and can be driven using only one I/O pin. You can hang several off one I/O pin and they can be powered from the Stamp end of the wiring. If you decide to use them, you will need to use a BS2p/pe/px Stamp since the other Stamp models do not support the 1-wire protocol. Look in the Stamp Manual for the OWIN and OWOUT statements.
  • ChetChet Posts: 150
    edited 2009-02-08 23:50
    You could use a 4 to 16 decoder (74hc154 or equiv.) for the RST line and select the individual units to read the temperature. This will work but might slow down the speed of reading them.

    regards
  • technoobtechnoob Posts: 21
    edited 2009-02-09 01:43
    '

    Thanks guys.···· Im on my way..





    technoob Randy C
Sign In or Register to comment.