problems with DS18S20/DS18B20 and DHT22 sensors

aderito · Post by **aderito** » Sat Dec 23, 2023 9:24 am

Hello, after updating flowcode version 8 to version 10 I am having problems with the components: DS18S20/DS18B20 and DHT22.
in the new version (10) I can't get either of these two sensors to work even after switching to different clock speeds.
So I come here to ask for help but I suspect there may be a bug in the new version of flowcode because I still have the old version (8) installed and the project works perfectly in this one.

Post by **chipfryer27** » Sat Dec 23, 2023 10:14 am

Hi

Can you attach your v10 project

Regards

Post by **jgu1** » Sun Dec 24, 2023 11:13 am

sorry DHT22 for me also not working in FC10. I have to go back to FC8, then it work?

The att. project is a project open in FC10 from FC8.

Br Jorgen

aderito · Post by **aderito** » Sun Dec 24, 2023 6:24 pm

the first attachment is in version 8 and the second is in version 10 which does not work

aderito · Post by **aderito** » Sun Dec 24, 2023 6:28 pm

the DS18S20/DS18B20 sensor I can't physically test because at the moment I don't have any available but using PROTEUS I can't get this sensor to work

aderito · Post by **aderito** » Wed Dec 27, 2023 6:16 pm

Attached is a simple test created with fcv10 (does not work) and a simple test created with fcv8 that works perfectly.
Furthermore, I made "version 8" from the file created with "version 10"

Post by **chipfryer27** » Thu Dec 28, 2023 3:48 pm

Hi

In the Evil Lab today so I had a look around at what I have but unfortunately I don't have any DHT22 modules but I do have DHT11 modules, both use one-wire so.....

I created charts in v8 and v10.

The charts use an EB083 combo-board connected to a multiprogrammer with a PIC16F1939 running at 19.xxxMHZ.

The chart initialises the display then enters a loop.

In the loop we wait for a button to be pressed before sampling the sensor.

According to the component, SampleSensor returns 0 for success, 1 for No Comms and 2 for Checksum Error.

The chart branched depending on result. If 0 then it would go on to display humidity and temperature, if 1 it would inform of comms error and if 2 it would inform of checksum error.

In both charts the sensor returned 1, meaning No Comms.

Connecting a Logic Analyser set to decode 1-wire / DHT11/22 provided the following information

: DHT11_v8.jpg (31.04 KiB) Viewed 1455 times

Zooming in we can see the sensor actually responded with correct readings

: DHT11_v8_zoom.jpg (42.96 KiB) Viewed 1455 times

The same results were obtained using v10.

Changing the chart to display results if a "1" was returned (instead of a 0), the chart displayed the correct readings on hardware on the display.
It would seem that in both v8 and v10, Flowcode is either returning incorrect values, or there is a typo in description in that it should read 1 for success.

I'm not sure if this helps with your DHT22 issue or not.

Although still connected to a DHT11, I changed the component to a DHT22 just to see what happens. Whilst I wasn't expecting much really I was interested to see what was being transmitted. The DHT11/22 decoders didn't register anything but 1-wire caught Resets. Same with v8.

: DHT22_v10_zoom.jpg (29.31 KiB) Viewed 1455 times

Regards

aderito · Post by **aderito** » Sat Dec 30, 2023 11:20 am

Hello, I noticed an error in the flowchart in the Switch icon......
I forgot to declare the variable in this operation so never exit this loop....
my distraction...
Attached I will post the correct flowcharts

aderito · Post by **aderito** » Sat Dec 30, 2023 11:48 am

hello,
I took some screenshots during the simulation with Proteus and it can be seen that in the "dht22 fc10" capture the times are somewhat different from the other captures.
I emphasize that the dht11 component works well in both fc8 and fc10