Help needed with Dew Heater & Module

[Trev-NI]

Camera setup and layout looking good so far.

Phase 2 - add Dew Heater before installing in enclosure.
I am using the example as in Dew Heater Module documentation.

I attach a photo of my setup less the dew heater ring and power supply.

First question - is this sensor suitable? Bought because it is an SHT31.
If not correct can anyone recommend a module available in UK known to work.

I have it hooked up as per the sample diagram. Data being the green wire to Pin 3 and Clock the Yellow to Pin 5.

I have the Module enabled in Periodic jobs.

Settings for Sensor, Heater and Dew control as shown all others not changed.

Debug shows Failed to read sensor

Relay showing power and relay on LEDs

Any help much appreciated.

[Alex-developer]

Few things

1. Are you sure thats an sht31? Looks more like a DS18B20 to me
2. If it is an sht31 then is i2c enabled on the pi?
3. Whats the output of

i2cdetect -y -a 1

Both the sht31 and DS18B20 will work with the dewheater module

Alex

[Trev-NI]

Hi Alex
output and some info on the SHT31 from Amazon

[Trev-NI]

Update: I have enabled i2C on the Pi. and went back to the Heater Module settings. I have placed in the module dew control settings Limit 4 and a Forced temp of 5. When I save and check the debug I am seeing: Result - Temperature outside limit temperature 20.64. dew point 11.37. I take it the sensor is working of sorts? The red and green leds on the relay module are still both lit. on the Overlay Editor from Variables Manager there is a variable for temperature which I have enabled - is this the reading of my sensor? It is not showing on the Live view. Any suggestions to test or proceed?

[Alex-developer]

All of the dew heater variables are prefixed 'DEWCONTROL', 'DEWCONTROLAMBIENT' is the temperature read from the dew heater temperature sensor.

I woud look at what the actual gpio pins are doing, some relays don't like being driven directly from gpio pins. Its looks like a pi 4 so use the following command to display the status of all of the gpio pins. Find pin 20 in the list and chnage the dew heater module settings and see if it changes

raspi-gpio get

[Trev-NI]

Thanks - I can see the variables OK now in the all variables not loading for some reason. Re the the command I se on gipo20 level= func=output pull=none. Can you clarify what it is you need me to do re the heater settings please

[Alex-developer]

Thanks - I can see the variables OK now in the all variables not loading for some reason. Re the the command I se on gipo20 level= func=output pull=none. Can you clarify what it is you need me to do re the heater settings please

For gpio 20 you should see something like

GPIO 20: level=0 func=OUTPUT pull=DOWN

the level=0 indicates that the pin is off so the relay should also be off. If it shows

GPIO 20: level=1 func=OUTPUT pull=DOWN

Then since level is 1 the relay should also be on.

So to test this adjust the forced temperature value in the module so that you know the relay should be on or off and then check with the gpio command

[Trev-NI]

First Alex thanks for your patience, I really do appreciate it and I understand it must be frustrating for you knowing that I know very little about all things Pi.
Here is a screen grab of the code line: 20 showing level=0 but pull=none. The relay is on red and green leds lit and tested with continuity. Is this an indication of a problem with the relay module or connection? I have a new relay being delivered tomorrow if required.

[Alex-developer]

First Alex thanks for your patience, I really do appreciate it and I understand it must be frustrating for you knowing that I know very little about all things Pi. Here is a screen grab of the code line: 20 showing level=0 but pull=none. The relay is on red and green leds lit and tested with continuity. Is this an indication of a problem with the relay module or connection? I have a new relay being delivered tomorrow if required.

No problem at all more than happy to help :-)

You could try the following two commands

Turn the relay on
raspi-gpio set 20 op dh

Turn the relay off
raspi-gpio set 20 op dl

Try those and see what the relay does

[Trev-NI]

Relay success - the new relay worked first time! This one had a switchable signal level of 5v or 3.3v and an input of 5 or 3.3. I left input at 5 and the switch was on 3.3 so I just give it an go and - hey presto!
Next - adding dew heather to the overlay - I see 3 entries in the Variable Manager - All Variables - but when I click on any of them (plus button) they are not showing. What am I missing?

[Trev-NI]

Sorry - just found the correct ones at the end of list 3 - too many birthdays!