[Tutorial] - Attaching DS18B20 temperature sensors to a Smart Implant

[Tim__ 126]

The Smart Implant can have up to 6 temperature sensors added to it, which makes it handy for climate control applications.  Here is a guide based on my experience, hopefully it helps you avoid the frustrations I had.

 

1.       Buy the sensors from a reputable source. The DS18B20 is manufactured by Maxim Integrated (ex-Dallas Semiconductor). There are many counterfeit sensors out there (eg Chinese company CXGAS) that either will simply not work, report incorrect readings, or stop working after a short period.  If the sensor is built into a probe it can be difficult to determine a counterfeit unless you open the casing, which can be difficult due to epoxy encapsulation. It seems most sensors bought on eBay, Aliexpress, Banggood etc are counterfeit.   See more on this here:

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2.       Keep the length of the lead between sensor and device under 3 meters, otherwise there may be synchronisation errors.

3.       A 4.7k resistor is required as a pullup from the DATA to VCC line.  If the DS18B20 is built into a probe, the resistor is probably not included.

4.       Where the DS18B20 device is soldered to a small daughter board, be careful as the PCB tracks may not connect directly to the corresponding jumper pins – instead the connections may be rearranged. Use a multimeter to confirm the pinout.

5.       Up to six sensors can be used, connected in parallel. The leads should all be the same length, to ensure the signals stay synchronised. Regardless of the number of sensors, a single 4.7k resistor is required as a pullup from the DATA to VCC line.

 

In order to show the temperature device slaves in your Home Center devices screen:

1.       Power down the device

2.       Wire the sensor(s) up, including the resistor

3.       Move the Smart Implant  very close to the Home Centre

4.       Power up and click the “Reconfigure Device” button in advanced options.

5.       You will need to delete the device and re-add it if you have changed sensors, as the internal sensor serial number identifiers will have changed.

6.       The temperature sensors will appear as additional Slaves.

 

When attempting to add the device, if you receive the error message: "ID xx: System hardware failure. Read the manual", this is a good indicator you have a clone sensor.

 

Set Parameters 67 and 68 as required, so that regular temperature reports are sent.

 

Note that the Smart Implant contains an internal temperature sensor.  This is likely to over-report air temperature, because the sensor is located inside the device and that will make it slightly warmer.

 

If this guide helped you, click the Heart symbol below to say thanks.

[Joost347 1]

Hi Tim, 

 

thank you for your tutorial. Is it also possible to make a picture of your set up?

 

thanks in advance,

 

Joost

[Tim__ 126]

Hi @Joost347, glad this was of use. Have a look in the manual, diagram 3 shows how to connect it:

 

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[MarcoSmartForYou 6]

hello Tim,

 

i got HC3,

 

i tryed to follow all fibaro manuals and your instruction, but i'm stucked, can you pls check what am I doing wrong?

 

it's the first time i use a DS18B20 sensor.

 

i attach you some pics, 

 

i wired everithing as is written in manual,

 

i did your procedure a lot of times,

 

i also tryed to factory default smart implant.

 

i don't understand what am i expected do see in "device" page.

 

I also see that parameter in HC3 starts from 24.. i see in some guide that i have to change some "lower" parameter

 

i think that those parameter are moved to "advanced" as you can see in the pics,

 

i see that there are 2 different analog input, is there any difference?

 

this is not a 0 - 10 sensor, i see other post in other forum saying that you don't have to touch this parameter cause you are acting on "multilevel sensor" only. is this correct?

 

i attach you also a foto of the type of sensor i'm using, 

 

thank you

 

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Edited November 17, 2021 by MarcoSmartForYou
missing information

[RH_Dreambox 189]

@MarcoSmartForYou
The DS18B20 is a special temperature sensor, but the humidity sensor you have can not be connected as a DS18B20 because it is not a DS18B20 sensor.
You have asked the question of how to connect your sensor in another post and which I have answered.
If you read that post, you will understand why the sensor does not work.

 

@MarcoSmartForYou

EDIT

It may work to connect the sensor directly to the Smart Implant, so try connecting it as my picture describes.
You need two different power sources because the sensor can only be connected to a maximum of 5 V and Smart Implant requires at least 9 V to work.
No extra resistance is needed. (Also not needed for the DS18B20 temperature sensor)
Check in your sensor's data sheet which output voltage you should enter, 0-3 V or something else.
You should be able to see some measured values in HC3 but they may need to be calibrated (change Min and Max voltage or measuring range).

 

If you want measured values more often, you can change parameter 63 to 0.1.

 

EDIT

Important!
First watch this video which is about good and bad sensors.

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Edited November 19, 2021 by RH_Dreambox

[MarcoSmartForYou 6]

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THANK YOU FOR THIS!!!!!!! 

 

I got one good news and a bad news,

 

the REALLY GOOD ONE is that your scheme is perfect! i'm getting some data and i owe you a bottle of good wine!!

 

the bad one is that i got some "inverse" readings. 

 

if i put water in glass i read 0% if i leave it i get 100% ?

 

is it because i got a "cheap" sensor? (can someone suggest me some good sensor in this case?)

 

 i got 3 different sensors, aesthetically identical, i see different voltage for each sensor. 

 

datasheet says 0-3V but if i put 0-3 it does not work. is this tension the voltage between yellow wire (signal) and GND?

 

i tryed to make this measurement with this 3 device i got and i get different readings:

 

first:

at0%      2.7v
at100%  0,930v 

 

second:

at100% 4,25
at0%     3,13

 

third:

at100% 1,0 v

at0%     2,10v

 

are those parameter good? i think a have broke two of them in some way....

 

if i understood well, more water, less resistence, more tension. is this "reverse" normal? have i bought the wrong sensor 3 times? ? am I missing something?

 

 

thank you guys!!

 

 

have someone noticed that there are 2 "analog input W/O pull up" possibility? is there any difference between them? (see attach 1)

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[RH_Dreambox 189]

@MarcoSmartForYou

Nice that you have managed to make it work (almost)
Since the sensor seems to work differently than I thought, you can start by changing the measuring range.
Change the configuration so that 0V = 100% and 3V = 0% so it should behave correctly (I hope).

If you want a more accurate scale, you can also change to 0.9V = 100% and 2.7V = 0% (your first sensor).

The fact that the sensors show such different values may be due to the fact that you have had too high an input voltage on the sensor and that they have been damaged.
Also remember to clean the sensors as grease from your hands can cause incorrect values.

 

And yes, you can connect two sensors to a Smart Implant.
You are now using Input 1 which is the yellow cable. The next sensor you connect to the green cable which is Input 2.
If you want to connect more sensors, you must get another Smart Implant.
Your offer of a bottle of wine sounds nice. I can pick it up if I go to Italy at some point

 

EDIT
I thought you would configure Analog input with "W/O pull-up".
Have you configured the sensor as "W/ pull-up" ???

 

EDIT

Important!
First watch this video which is about good and bad sensors.

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and if the sensor reacs slowly

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Edited November 19, 2021 by RH_Dreambox

[RH_Dreambox 189]

@MarcoSmartForYou

It's a bug in the Italian translation.
It should be con pull-up and senza pull-up.

 

 

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[MarcoSmartForYou 6]

hello guys,

 

sorry if i didn't show up of a long time,

 

thank you for support, just to let you know that everything is working now,

 

i'll report this minor bug to Nice Italia, to let them work on it,

 

let me know when you are going to program your travel to Milan to collect your bottle of wine! ?

 

have a nice day guys!! 

 

 

[S.V. 0]

 Tim__ @,

 

Thank you for info.

 

The schematic shown in the manual FGBS-222-T-EN-rev.1.2.6.pdf under "4.3: Connection with DS18B20" does not show your #3 instruction "A 4.7k resistor is required as a pullup from the DATA to VCC line. "  The schematic labels the DS18B20 leads as:

• GND -- GND
• DQ -- SD
• VDD -- SP

Q#1: This is not helpful for a beginner.  Would an equivalent instruction be "connect a 4.7k resistor from DQ/SD to VDD/SP"?  Could or should Fibaro update the PDF to show the resistor?

 

Q#2: I put the resistor in line and followed the reconfigure/remove/add instructions and the FGBS-222 now shows 4 temperatures that make sense, the highest of which I assume is internal to the device (image attached). However I have 6 of DS18B20 connected, why are only 3 showing?  All 6 show when the array is connected to a Raspberry Pi with 1-wire library installed (image attached).  Note similar temperature readings.

 

Q#3: Is there any means to extract the 1-wire serial numbers of the DS18B20 devices via FGBS-222? What strategy do you suggest to logically associate sensor-X to location-X?

 

I'm an expert in a completely different technology and I know for a fact expert advice is under appreciated.  Thank you very much for participating in this forum.

 

~Kev

 

 

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[S.V. 0]

Answering part of my Q#2: Getting all 6 of the DS18B20 sensors recognized.  Apparently the FGBS-222 must be factory reset and power cycled after the sensors are connected.  According to the manual, removing it from the Z-wave network also causes a factory reset.  Assuming you have your FGBS-222 included but sensors are not reporting accurately:

1. Connect the DS18B20 sensors you want to report
2. Set your Home Assistant Z-Wave in exclusion mode
3. Triple-press the FGBS-222 service button
4. Note Home Assistant confirming exclusion
5. Power off FGBS-222 for 5 minutes or so
6. Set Home Assistant Z-Wave inclusion
7. Power on FGBS-222 
8. Triple-press the FGBS-222 service button
9. Home Assistant eventually requests 5 digit code for FGBS-222
10. Home Assistant gives an inclusion timeout error but continues to interview FGBS-222
11. Something like 10 minutes later, Home Assistant shows FGBS-222 with temperatures from 1 internal sensor and my 6 DS18B20 sensors.

The attached image shows the sensor results.  The 32.5C (90F) is apparently internal, but the device feels like room temperature when I touch it.   The six sensors range from 19.6C (67F) to 20.1C (68F), but this is in the same +/- range as I showed yesterday when I connected the sensors to a Raspberry Pi with 1-wire library. 

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[Tim__ 126]

@S.V.  Unfortunately Fibaro documentation is not great, and I had to spend a lot of time experimenting to get the sensors to work.  There is a steep learning curve for beginners! However, I'm glad you found my tutorial useful. 

 

To answer your remaining questions: Q1 (updating the manual diagram) is a question for Fibaro.

 

Q3 (which sensor is which)...I worked this out by warming each sensor in my hand, and seeing which one responded in the mobile app.

 

Have fun with your new system!

[krza 3]

On 6/22/2025 at 10:04 AM, Tim__ said:

To answer your remaining questions: Q1 (updating the manual diagram) is a question for Fibaro.

 

This is quite annoying. And I really don´t understand that it´s still not there. Just bought a Smart Implant and a few sensors and tried to connect one of them but did not get any reasonable data. Then I found the information about the resistor here and hope that this is the reason. But where to get a single 4.7k resistor from ... again, it´s quite annoying and actually a nonprofessional (on the Fibaro side).

But thanks for all the posts above ... will read it again when I found a resistor and try again.

 

Edit:

Meanwhile I looked for a clarification for teh exact value of 4.7k and found that it seems to be a rough target value only. Another user talked about 2k only and for short wires even a higher value than 4.7 might work. However, I found a few 1.5k resistors which I will try to connect to 4.5k.

Edited January 10 by krza
further information

[krza 3]

Hi, it seems that there is some help required ...

 

I had connected the 4.5k and one od the DS18B20 but did not really get anything. In the meantime I have created a wild wiring in order to connect 6 of the sensors somehow but the result is actually the same: Nothing. The only sensor which can be seen is the internal one.

 

I wonder if the deice must be configured in order to know that I want to use it for 6 sensors (thus to configuration A from the Fibaro manual). But I read the manual again and cannot find any (clear) hint what to do in order to reach that. Also the posts above don´t seem to mention a specific action but actually let assume that the default settings should work.

 

Maybe my expectation is wrong. My assumption was that the sensors are detected as such when connecting/resetting the smart implant and shown in the dashboard accordingly. Also I expected to see the temperature diagrams as I do for the internal sensor. Is that wrong? Can I get the values programmatically only?

 

The below screenshot shows what I can see in the dashboard.

• 127.0.1 (129) is the internal sensor.
• 127.7.1 (138) seems to be the same sensor, at least it shows the same values.
• 127.3/4/7 (133/134/137) are stated as multi level sensors but without additional details. In the according previews 134 and 137 show a value of 0, 133 shows a 0.26 (always, no change).

Any ideas are welcome to get this fixed. Unfortunately I have no other device which I could use to ensure the proper operation of the sensors.

 

 

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[Tim__ 126]

Hey there @krza,

 

To answer your questions:

- "I wonder if the deice must be configured in order to know that I want to use it for 6 sensors"...no you don't need to worry about this.

- And yes, you should see all 6 temperature sensors in your list.  For me, they appear as additional lines after the last entry (i.e. after 127.7.1, which is the internal temperature of the device)

 

Can you confirm that you've followed the tutorial steps 1 to 5?  Especially, where did you buy the sensors; and did you exclude and then reinclude the Smart Implant AFTER you finished your wiring?

 

I'd suggest breaking the probelem down; and trying to get one sensor working first, then moving on to having all 6 once you have that working.