PDA

View Full Version : looking for a good temperature sensor



robot maker
08-14-2008, 03:48 PM
i am looking for a good temperature sensor for my hand design,it will be on each finger
and I2C or analog output,if analog output like the phigets temperature sensor that uses TC1047 will need 10 input analog circiut,all ready have a chip that will fill my needs
or teperature sensor that has I2C bus ,i have a few samples or thermistor k type with circuit
what is the best sensor for my hand also finger is 3/4 inch width

Adrenalynn
08-14-2008, 04:15 PM
http://www.sparkfun.com/commerce/product_info.php?products_id=8227 ?

robot maker
08-14-2008, 05:28 PM
looks like a good sensor,but 2 bad things i see has humidity i dont need and the cost $130 per hand besides all other other sensor motors servo,s and electronics
robots are getting to cost of a good used car,just bought one for my wife for anniversary gift toyota cellica 2004

JonHylands
08-14-2008, 09:54 PM
Digikey:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LM19CIZ-ND

$1.22 (CAD) in single quantities. Give it ground and plus 5, and it gives you an analong voltage proportional to the temperature.

Adrenalynn
08-14-2008, 11:07 PM
How about just a thermistor? I can get those down under ten cents. :)

jes1510
08-15-2008, 10:16 AM
I have never used one but the LM34 and LM35 temperature sensors have analog outputs. The LM34 output 10mV per degree F and the LM35 outputs 10mV per degree C.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1966391;keywords=lm35
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1966391;keywords=lm34

Adrenalynn's suggestion of a simply thermistor is probably your best bet but their output is usually not very linear. It depends on your preference.

jes1510
08-15-2008, 10:18 AM
BTW a search for "I2C temperature" on Digikey's site turns up these results:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1966391;keywords=i2c%20temperature (http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=1966391;keywords=i2c%20temperature)

robot maker
08-18-2008, 12:04 PM
that maybe one way to go,not because of costs,but size of package ,temperature sensor needs to fit on top or under the FSR of each finger,surface mount sometimes flat,also less the wires from temperature sensor to circuit,using a thermistor you need a good stable bridge circuit and a buffer amp


How about just a thermistor? I can get those down under ten cents. :)

robot maker
08-28-2008, 10:51 AM
looking at thermistors i see all mostly fairly round and 3mm thick,i am thinking surface mount might be best way to go
question is -writing the code for a-d converter alot easy then writing the code for I2C bus
other problem might be hard mounting it in 3/4 inch finger,looking to see if they have a surfboard that will fit and take smt temperature sensor or just solder wires to the chip and use thermo tape
any ideas on this
another idea is on thermistor is to drill a hole inside the aluminium 3/4 inch square tubing i am using for each finger ,and place the thermistor inside the hole and FSR on top and thermo tape on bottom

Adrenalynn
08-28-2008, 10:57 AM
>> question is -writing the code for a-d converter alot easy then writing the code for I2C bus

Depends on your capture device.

robot maker
08-28-2008, 01:06 PM
i guess first is to get a sample of each type of temperature sensor,smt,to-92 like JOH hylands gave me link to,and thermistors and test them on my design to see how they fit and work,then find out what processor i will need to interface it,might for now use a basic stamp for testing,since it easy to use and program and used a a-d chip with it
i have found out that basic stamp is a great chip for testing sensors and other circuits ,before buying the right processor for my needs,a-d chip will use is 12 bits,temperature on a hand design doesnt need to be super precision,just hot from cold mostly,that microprocessor board you gave me a link too seattlerobots site seems to be almost perfect,only wish it has more a-d channels
maybe buy one for each hand and have roborealm control both of them,i know you can control 2 or more webcams with roborealm,so i am thinking i can control 2 microprocessor boards too
then i wont need a seperate a-d to I2C BUS


>> question is -writing the code for a-d converter alot easy then writing the code for I2C bus

Depends on your capture device.

ScuD
08-28-2008, 04:07 PM
If you really wanna jump in head-first, try a PIC microcontroller or AVR or something.
More than plenty of freeware compilers can be found, some with limits but still more than able to do what you need.

In any case it's more a matter of what you wanna do. If you're interested in the electronics part of it all, grab a micro, if it's more the programming that does your trick, get an arduino or the likes.

robot maker
08-28-2008, 04:59 PM
if you read my last post to my thread that is what i said to use avr or adurino/wiring board that uses avr processor,mostly because freeware is free and seems little easy in programming
the basic stamp is only for testing,its way to slow and not many inputs for uses in robots
still can be used by not high end robots
need atleast 20 channels of a-d and 4 channels of pwm so the one adrenalynn gave me a link to has 15 channels and uses avr processor,so buying 2 is a good idea instead of maybe A-D TO I2C 10 channel,and have 15 a-d channels per hand with have channels left for another set of FSR on the palm if needed or other sensors


If you really wanna jump in head-first, try a PIC microcontroller or AVR or something.
More than plenty of freeware compilers can be found, some with limits but still more than able to do what you need.

In any case it's more a matter of what you wanna do. If you're interested in the electronics part of it all, grab a micro, if it's more the programming that does your trick, get an arduino or the likes.

robot maker
08-28-2008, 05:05 PM
this is the link that adrenalynn gave me that really looks good for my project and will interface with roborealm
http://www.societyofrobots.com/axon/ (http://www.societyofrobots.com/axon/)
thanks again adrenalynn



If you really wanna jump in head-first, try a PIC microcontroller or AVR or something.
More than plenty of freeware compilers can be found, some with limits but still more than able to do what you need.

In any case it's more a matter of what you wanna do. If you're interested in the electronics part of it all, grab a micro, if it's more the programming that does your trick, get an arduino or the likes.

robot maker
08-31-2008, 12:22 PM
i seem to like jons idea of a sensor ,sofar will buy a couple of different types to try out
going to use analog output types and interface to axon board a-d,it simple,and easy
size might matter,since i need to place under the fsr sensor,using thermistor not a great idea since it needs a stable current source then a bridge circuit,we do make temperature meters,but with thermocouplers,k and j type,and would be hard to interface to my circuit,asked guys at work and they said the best is to-92 case or smt with analog output like LM19 or LM34

any ideas on mounting them ,one idea i have is to drill a hole under the fsr and place to-92 or smt sensor in it and have metal plate or themotape to hold it in place