Comments on: How to use the DS18S20 and DS18B20 temperature sensors with Arduino

By: Arduino, LED-s, LM35 and DS18B20 or temperature sensors. » Ogalik

Arduino, LED-s, LM35 and DS18B20 or temperature sensors. » Ogalik — Mon, 29 Aug 2011 05:47:46 +0000

[...] using digital temperature sensor, DS18B20 proved to be more of a challenge. I did look at http://stuff.nekhbet.ro/2009/08/23/how-to-use-the-ds18s20-and-ds18b20-temperature-sensors-with-ardui... and some other examples, but unfortunately forgot to purchase 4.7Kohm resistors. Back to shop [...]

By: E.A.Neonakis

E.A.Neonakis — Thu, 28 Apr 2011 11:03:01 +0000

I think you should make clear that this code does not work for DS18B20.
I doubt that it works for negative temperatures even for DS18S20, !tr is logical inversion, while you need bitwose inversion ~tr to negate a 2′s complement integer number.
The code for DS18B20 is actually very simple:
float celsius=(short int)((data[1]<<8)+data[0])/16.;
return celsius;

By: bmo

bmo — Tue, 19 Apr 2011 06:09:46 +0000

nm if its not at high temps you’re fine

http://pdfserv.maxim-ic.com/en/an/AN203.pdf

By: bmo

bmo — Tue, 19 Apr 2011 05:18:09 +0000

in parasite mode you should still connect the third pin to ground so says the datasheet…. I’m interested in Vdd wiring, I’m hoping this will give me faster temp returns does anyone know where i could find this before i venture into the unknown…

By: andrew

andrew — Tue, 15 Mar 2011 06:19:47 +0000

Andreas, I think you’re correct. The resolution is different between the 18S20 and the 18B20, so some bit twiddling is required.

By: Andreas

Andreas — Tue, 22 Feb 2011 07:07:17 +0000

I use a DS18B20 and then your code returns a very high temperature:

Temp = 144.61 F or 62.56 C

But with the tutorial from onewire I get realistic temperatures:
http://www.arduino.cc/playground/Learning/OneWire
> 23.93 C

So I think this code only works for DS18S20 and not for DS18B20?

By: Igor1024

Igor1024 — Mon, 31 Jan 2011 09:24:22 +0000

Scheme is wrong a bit. Vcc pin and grount should be shotened/

By: Chris

Chris — Thu, 27 Jan 2011 17:54:41 +0000

Thanks a lot!!

This was exactly the code i was looking for! Al the other code’s on the internet are very large, en they don’t give you the right info you need!

Thanks again!

By: Temperaturna postaja « gregag

Temperaturna postaja « gregag — Wed, 05 Jan 2011 21:04:03 +0000

[...] beleženje temperature sem uporabil dva dallas 1-wire digitalna DS18S20 temperaturna senzorja in analogni LM335. Eden izmed Ds18s20 je mišljen kot senzor v ohišju skupaj z LM335, drugi pa [...]

By: Pierre

Pierre — Thu, 16 Dec 2010 21:59:40 +0000

Hi,

i can confirm the problem with the negative temperatures. I also think the measured temperature is +-3° above the real temp.

Simon, did you ever get this working?

By: Tracy

Tracy — Fri, 27 Aug 2010 13:03:23 +0000

Just to let you know that this has been really helpful, thanks

By: using a DS18B20 temp probe

using a DS18B20 temp probe — Fri, 21 May 2010 23:03:50 +0000

[...] to this guy How to use the DS18S20 and DS18B20 temperature sensors with Arduino – Dedication to DIY and pr… you only need one resistor per ??? devices. Reply With Quote [...]

By: SimonL

SimonL — Tue, 09 Mar 2010 23:28:45 +0000

Hi Sorin, Hope the exams went well. Did you get a chance to try it? I confirmed it’s not a grounding issue – almost certain it’s coding.
Regards,
Simon.

By: Ivan

Ivan — Sat, 30 Jan 2010 16:22:54 +0000

Thanks for this, very helpful in getting up and running with these sensors!

By: Trimbitas Sorin

Trimbitas Sorin — Wed, 20 Jan 2010 12:45:23 +0000

Hi Simon,

Try to ground pin 3 as tinux suggested. I’ll run some more tests tomorrow because I’m off work and will get back and modify the post if it is the case.

Best wishes

Sorin