Ds18b20 Temperture Sensor

[jimmy88]

i have ds18b20 and it reads temperature im using the debug command and the values is shown on the debug window
anyway the temperature reading is realistic but when i try to apply heat near to the sensor it takes time to let the temperture increase


is it ok to touch the sensor by a heat source like an iron to make the temp increase faster or the sensor is going to damage
because i don't touch the sensor i just apply heat near to the sensor

i have onother quesstion
whats RSSI ,STAT, IND on xbee module stand for

 

[testerrrs]

RSSI is Recieved Signal Strength Indicator. I don't know about the others, sorry.

 

[westaust55]

The DS18B20 is design to work over a temperature range of -55°C to 125°C. It is accurate to ±0.5°C over the range of –10°C to +85°C. SO suggest 125°C is the maximum allowable temperature and the error may be greater.

From my observation there is a slight thermal lag when heat is applied directly to the body of the DS18B20 – such as when using your fingers to raise the temperature for checking.

The tin-Lead type solders typically have a melting point around 175 to 183°C and the soldering iron tip particularly of non-controlled irons will be higher than this to actually melt the solder.
Accordingly. I would not suggest placing your soldering iron in contact with the DS18B20 IC.

 

[marcos.placona]

It may well be something on your code (like a long pause maybe). Try to remove all the pauses on your code, and run a simple

main:
readtemp 1,b1 'read value into b1
debug b1
goto main

This should give you accurate results. Just remember that the conversion can take up to 750ms

Here it changes whenever I put my fingers on the sensor (considering a small delay of +/- 750ms)

 

[Andrew Cowan]

I find that holding a DS18B20 gives a noticable responce - if not, either dip the body (not the legs) in hot or boiling water, or you can give it a QUICK blast with a heat gun.

Andrew

 

[marcos.placona]

Even if you blow some air on it (from your mouth will do), you should get the temperature increased by at least 2 degrees. Of course it will vary a bit in case you are doing it inside of a sauna, or if you're in a desert

 

[manuka]

Good suggestions, & I'll add that DEBUG is a real command slow coach-you'll get brisker results with SERTXD/F8.

 

[Dippy]

Don't stick a soldering iron tip onto the device.

Jimmy says 'takes time' - great, but what sort of duration? Are we talking about mS, seconds, minutes..?
It's like saying that your car goes 'really fast'.

Apply heat 'near the sensor' - whats the heat source? Radiant? Hot air? Mother-in-Law's breath?

As suggested, is it your code?
Have you remembered that reading a DS18xx isn't instant?
Have you remembered your schoolboy physics about heat conduction and heat capacities?

 

[hippy]

Blowing on it, waving a notepad over it, neslting it in your armpit ( or somewhere more daring ! ) should all cause a noticeable change of temperature.

There will always be some thermal lag but I've never measured it - Have you checked the datasheet ? I wouldn't recommend touching it with a soldering iron either.

 

[jimmy88]

thxxx
i stick the sensor to a bowl that has a boiled water and the temp increased faster

any idea wut do STAT and IND stand for

 

[westaust55]

Looks like the general concesus was not the put the soldering iron tip against the temp sensor.

Now, do you want to give us a hint as to where the STAT and IND come from that you are referencing? Manual, datasheet, etc. Page No?

 

[hippy]

From AXE210_XBee.PDF ...

The AXE210 board has three LED indicators.

RSSI connects to the XBee RSSI pin (pin 6)
STATUS connects to the XBee ON/Sleep pin (pin 13
IND connects via Jumper 3 to either XBee Associate pin (pin 15) or Transmit pin (pin 11)

RSSI indicates the XBee received signal strength
STATUS indicates whether the XBee module is active/sleeping
IND indicates whether the XBee module has associated with another module (Associate position) or is transmitting data (Transmit position).