Temperature Sensing using DS18B20 Digital Sensors

the1andonly · Post by **the1andonly** » Fri Aug 21, 2015 6:08 pm

I know some people have used these with an arduino to measure temperatures around the Bongo.
My system has been in use since oct 14. I have 5 sensors sourced from china/ ebay ( water proof? sealed stainless tubes)
Recently 4 have taken to intermittantly show the 85 error signal but only with engine running (diesel 4wd) engine off all sweetness and light.
I am running the arduino via USB and a usb convertor to 12V (LB)
is it a sensor issue as 1 is totaly happy and 3 have recently started playing up (only with engine running)
or a Voltage issue
(LB is solar charged) and split relay charger.
Cheap USB /12V device
or something else

mikeonb4c · Post by **mikeonb4c** » Fri Aug 21, 2015 9:03 pm

the1andonly wrote:I know some people have used these with an arduino to measure temperatures around the Bongo.
My system has been in use since oct 14. I have 5 sensors sourced from china/ ebay ( water proof? sealed stainless tubes)
Recently 4 have taken to intermittantly show the 85 error signal but only with engine running (diesel 4wd) engine off all sweetness and light.
I am running the arduino via USB and a usb convertor to 12V (LB)
is it a sensor issue as 1 is totaly happy and 3 have recently started playing up (only with engine running)
or a Voltage issue
(LB is solar charged) and split relay charger.
Cheap USB /12V device
or something else

Are the sensors suitable for the environment they are operating in (vibration, for example). Were they cheap to buy. Could the answer lie somewhere in this area?

Post by **g8dhe** » Fri Aug 21, 2015 9:58 pm

Can you move the sensor around the other inputs and see if there is anything common? The other thing is if the wiring is running parallel with any other internal looms you might be getting induction into them which can be quite significant voltages when relays and solenoids start operating, the devices aren't rated for automotive use so its always a concern, likewise if you relying on on the chassis for return.

the1andonly · Post by **the1andonly** » Fri Aug 21, 2015 10:35 pm

g8dhe wrote:Can you move the sensor around the other inputs and see if there is anything common? The other thing is if the wiring is running parallel with any other internal looms you might be getting induction into them which can be quite significant voltages when relays and solenoids start operating, the devices aren't rated for automotive use so its always a concern, likewise if you relying on on the chassis for return.

I was /am concerned about the quality of the supply spiking etc but parts have been in same position for almost a year.
all sensor parts have a a common earth via the arduino (3 wire mode)
The 5V to the sensors is via the regulated arduino supply, though supply to arduino is more suspect.
All 4 engine sensors are combined in 1 position in engine compartment and then joined to rad monitor outside (ie in the cab ) before going to arduino.
I see something to check (ie what is common about the problem devices)
the connection
the temperature of sensor
the rad (works) has a separate connection and is lowest temperature.

mikeonb4c wrote:
the1andonly wrote:I know some people have used these with an arduino to measure temperatures around the Bongo.
My system has been in use since oct 14. I have 5 sensors sourced from china/ ebay ( water proof? sealed stainless tubes)
Recently 4 have taken to intermittantly show the 85 error signal but only with engine running (diesel 4wd) engine off all sweetness and light.
I am running the arduino via USB and a usb convertor to 12V (LB)
is it a sensor issue as 1 is totaly happy and 3 have recently started playing up (only with engine running)
or a Voltage issue
(LB is solar charged) and split relay charger.
Cheap USB /12V device
or something else
Are the sensors suitable for the environment they are operating in (vibration, for example). Were they cheap to buy. Could the answer lie somewhere in this area?

cheap? same component (not assembly)
£6 for 5 from china
or £5 for 1 from UK
the same part, same silicon?
The temperature excursions are within spec
vibration?
the system works much better (poss no probs when engine off)

Post by **g8dhe** » Sat Aug 22, 2015 6:19 am

Not uncommon to have something fail after its been stressed several times, the spikes can sometimes be horrific to watch on a fast scope, you'll never see them on a meter at all.
If its working when the engine isn't running then there is a big clue!

novocaine · Post by **novocaine** » Mon Aug 24, 2015 8:21 am

voltage spike. try changing from pin 2 to pin 3 and altering the sketch, you may have fried a track.

can you not reach the plug to debug on a laptop?

the1andonly · Post by **the1andonly** » Tue Aug 25, 2015 6:34 pm

novocaine wrote:voltage spike. try changing from pin 2 to pin 3 and altering the sketch, you may have fried a track.
can you not reach the plug to debug on a laptop?

Yes i can debug using a laptop in van
which Pin 2 ,3 on DS18 or Arduino? thinking about it you must mean Arduino (you may have fried a track.

jimmo62 · Post by **jimmo62** » Tue Aug 25, 2015 7:36 pm

Also I believe they use a single wire bus (i.e. all sensors send their readings over a single shared common wire). If one goes faulty and does not share the bus properly it could affect the readings of the others. You could try disconnecting one at a time to see if it helps

the1andonly · Post by **the1andonly** » Mon Sep 07, 2015 6:20 pm

All sorted
just soldered all fresh connections and heat shrink. one wire may have been able to short to cars earth.
Thanks all

sotal · Post by **sotal** » Mon Apr 11, 2016 11:58 pm

the1andonly wrote:I know some people have used these with an arduino to measure temperatures around the Bongo.
My system has been in use since oct 14. I have 5 sensors sourced from china/ ebay ( water proof? sealed stainless tubes)
Recently 4 have taken to intermittantly show the 85 error signal but only with engine running (diesel 4wd) engine off all sweetness and light.
I am running the arduino via USB and a usb convertor to 12V (LB)
is it a sensor issue as 1 is totaly happy and 3 have recently started playing up (only with engine running)
or a Voltage issue
(LB is solar charged) and split relay charger.
Cheap USB /12V device
or something else

I'm tempted to make something like this.

What are you using to display the temperatures? Have you got it rigged to a buzzer if they get too hot etc? How did you attach the sensors? Any chance you could post up your code?

Thanks

the1andonly · Post by **the1andonly** » Tue Apr 12, 2016 9:21 pm

sotal
pragmatic rather than pretty.
The Led is a tricolour
blue normal
red alarm
there are 6 sensor (the inside sensor does not display but all values saved to sd card)
if value exceeds limit the sensor number on top line changes to alm and led is red. a buzzer can also be triggered.
sensor positions:
bottom hose, Next to scav fan sensor, front stub on head to rad, rear of head, autobox.
Held in place by jubilee clips, bolts or cable ties

will Pm code

sotal · Post by **sotal** » Tue Apr 12, 2016 9:24 pm

Thanks

I've got a few of the cheap clone boards and have used them for a few things so should be able to set this up but any code/diagrams would be much appreciated.

Sensors look cheap enough on ebay.

Temperature Sensing using DS18B20 Digital Sensors

Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors

Re: Temperature Sensing using DS18B20 Digital Sensors