WeatherDuino Forum

Hi everyone

Just wondering what people are using these days for their outside temperature sensors?

For many years I have been using SHT10, but sadly I have just used my last replacement I have and cannot seem to order any more.

I have found the life span of my last batch of SHT10 sensors have not lasted, usually the humidity fails first before the temperature; something that has been commended on here before.

I ordered form Alliexpress "a direct replacement" for the SHT10 which is a DHT90 but sadly it is not a "plug-and-play" direct replacement as I expected.

Has anyone had a DHT90 temperature sensor working on this Arduino project? I really haven't had a try and understand I probably need to play around with the different libraries but don't want to try if it is going to be a waste of time.

The product ordered is this, but the on-board chip which arrived does not meet that of the photo: https://www.aliexpress.com/item/4000895053325.html

My ideal cable run is 10 metres from the TX unit (version 3.12), so that sadly rules out SHT31 and SHT2x sensors from my understanding. On this TX board I have ground and leaf sensors also attached.

I am considering going back to DHT22 AM2320 sensors, how reliable, durable and accurate are people finding these units?

Thank you for reading,
Matt

After reading these forums and having a SHT11 fitted with a dust shield fail, I switched to the SHT31.  It's been around six months - all good so far.  It looks quite rugged.

Core Electronics - SHT31

Hi Matt,

Hope you are going well.

I don't have any experience with the DHT90 sensor, but it's supposed to be a direct replacement for the SHT1x. The fact that you received a different sensor from the sensor shown in the image may indicate that it is not a DHT90, but something else... without knowing exactly what sensor it is, it is difficult to find an Arduino library for it.
If I can find out anything else about this sensor, I will comment here.

Rgs,
Werk_AG

Hi everyone

Well I sourced some "genuine" DHT22 AM2302 following my inability to source any replacement SHT1X sensors.

Sadly I get some very strange outputs. I get no humidity data and temperatures range from -200 degrees to + 100 degrees.

I have four sensors and all give the same variable output.

I downloaded a fresh copy of the TX software version 7.0_b003 and ensured the correct sensor is set and the DHTxx library matches and ensured my Arduino program is compiling in version 1.6.21 for AVR boards.

I have run the debug mode on the TX board and provided below the serial output from this test. You will note the very first reading is correct before things go off script, the same pattern of numbers is repeated after the board is reset.

Any tips on what I am doing wrong with this sensor having not used it before?

I am thinking that it might be a library issue with the DHTxx. I have successfully got an Arduino Nano to successfully provide regular serial data outputs from these sensors using a different code and DHT library.

 

Quote:Serial Output from TX board in Debug mode:

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 27.40  Hum: 59.20
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 274.00  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 118.56  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: -125.12  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 59.52  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: -60.16  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 53.76  Hum: 0.00

-- RESET BOARD ---

Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 27.40  Hum: 59.70
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 274.00  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: 118.56  Hum: 0.00
 
Sending ID0...
  Sensor 0 - Temp: 0.00  Hum: 0.00
  Sensor 1 - Temp: -125.12  Hum: 0.00

 

Hello dear friend,

Right now I'm testing a DTH22 sensor with a Pro2 TX board v3.12 and latest TX software (7.0_b003) without any change and it is working as expected.

Here is some of the DHT22 readings I get on the serial monitor:


There is one thing I noticed from your pictures: The DHT22 pin3 should be left unconnected (the one you have connected to CLK).
Try disconnect the pin 3, then it should work.

Waiting to hear from you.

My best wishes of an Happy New Year.
Werk_AG

Thank you for taking the time to test your sensors and for your continued support of the old Pro2 system.

I have tested this again tonight without pin3 connected, but sadly no success. I have attached a screenshot of this in operation.

Attached are also two other screenshots of two different Arduino codes which I have been using to test the the temperature sensors and both codes work without issue. This does use a different DHT code library which was downloaded through the Arduino program.

I have repeated my tests on two different Arduino Nano boards and using two different computers to compile and test the codes, but I get the same results.

I note written inside the sensor under the white cover it says: "ASAIR AM2302 V3.1". Maybe it is a version issue with this sensor?

Any other ideas on what I might be able to do?

Thank you for your help once again.

I really don't know waht is happen. Did you tried to test the sensor with your test code with the sensor connected on the TX board as shown on the pictures?
The DAT pin for the DHT22 on the TX board is pin 6. Think you need to change the test code.

The DHT22 sensors I have look exactly as yours, even if different versions they should work the same way.

If the sensor works with your test code when connected to the TX board, as a last resource you may try to modify the TX code to use the DHT22 library that works for you. If you go this way take care, seems your library read the values as float numbers, while the original DHTxx lib read value as integers.

Rgs.
Werk_AG

Thank you for the suggestion of running my DHT22 test code directly onto the WeatherDuino board. I had not thought of doing this before.

Before this for testing purposes I was using a breadboard/prototyping board to test the Nano with the DHT22 sensor.

I have tested your suggestion this evening. Sadly I get the same results however. The test code works fine even when run off the WeatherDuino board, but the TX software does not. At least I know it is not the circuitboard at fault.

Attached to this post, I have included the WeatherDuino TX software with the libraries that I have been using for testing. It would be interesting to see what results other people get with the attached program?

If the attached WeatherDuino TX software works correctly for someone else with a DHT22 sensor, I will try and find an alternative source of these to see a different product functions any differently. I would rather not try and mess around with my own library or editing software to make my current sensors work.

Also I have attached the alternative library with the testing code as a comparison between the two libraries.

My apologies that this topic has moved from a hardware question to a software question. I was not expecting this outcome when I was looking for alternative sensors.

As always, thank you for your help.
Matthew

Additional photos of tonight's testing for reference:

(30-12-2023, 08:37)Palmyweather Wrote: [ -> ]...

I have tested your suggestion this evening. Sadly I get the same results however. The test code works fine even when run off the WeatherDuino board, but the TX software does not. At least I know it is not the circuitboard at fault.
...

That was my intention, try to eliminate anything which could be related to the TX board.
I checked everything again with the TX software, also tried with the library you provide. In both cases I can read the DHT22 sensor attached to the Pro2 TX board.

Here are some pictures:


With the original Pro2 TX firmware v7.0_b003:




Using the example from the DHT library you sent:




Picture of connections:



It like these mysteries, but at moment I haven't a single clue about why your sensor isn't being read properly.
Can you please post your whole Config_Options.h file so I could test with exactly the same config.

Rgs.
Werk_AG