SSR always on/off Depending on inverted/ not inverted setting

Greetings fellow members. so I have searched the community up and down looking for resolution to my problem. I have gotten close a couple of times with post like this and thisand this but alas I am unable to resolve my issue.


I am using a Brewpi2 (Canakit) with an ardruino uno R3 connected in the embedded schematic


When I set brewpi to run in either beer constant or fridge constant the arduino does not seem to send the correct signal to the SSRs. The SSRs are either always on or always off depending on the setting for inverted or not inverted. The onewire probes are reporting accurately and I am getting good data log. Dc voltage to the SSR control side reads just under 5 VDC. For the AC power side, I read 120 VAC when SSR light is on and 0 VAC when SSR light is off, indicating the SSRs are switching when the inverted/not inverted setting is toggled.

I am using the correct HEX file (10 I think) I am completely miffed.

I understand this set up is no longer supported, please accept my apologies in advance if this has already been addressed else ware, I am just hoping there is enough still using the old setup that they might have a solution to this issue.

Thank you in advance to any help.



Does the Arduino go into cooling or heating state? Or does it stay in idle?
Did you set it to fridge constant/beer constant?
Do you have a chamber sensor installed?
Please share a copy of your device list.

If your SSRs toggle with inverted/non-inverted, they hardware seems correct.

Thank you so much for the reply, I have to be honest I felt like Dorthy when I woke this morning and saw your reply. I was thinking the great OZ (you lol) is going to help. Thank you so much for your site and the support you provide, truly an amazing creation you have.

okay on to the issue:

Q) Does the Arduino go into cooling or heating state? Or does it stay in idle?
A) it does not seem to switch state, however I may not know exactly how to confirm that. What I have observed is when I run in “constant” (Beer or fridge) mode and make the set point different then the current reading, the SSR does not actively change state.

Q) Did you set it to fridge constant/beer constant?
A) yes see comment above

Q) Do you have a chamber sensor installed?
A) Yes, I have two onewire, one in the conical thermowell and one in the chamber

Q) Please share a copy of your device list.
A) Part list as follows:


Product name : solid state relay; model no. : bem-14840da
Current & frequency : 40A, 50/60Hz; output Voltage : 24-480vac
Control Voltage : 3-32vdc;

Adruino UNO

Microcontroller ATmega328P
Operating Voltage 5V
Input Voltage (recommended) 7-12V
Input Voltage (limit) 6-20V
Digital I/O Pins 14 (of which 6 provide PWM output)
PWM Digital I/O Pins 6
Analog Input Pins 6
DC Current per I/O Pin 20 mA
DC Current for 3.3V Pin 50 mA
Flash Memory 32 KB (ATmega328P)
of which 0.5 KB used by bootloader
SRAM 2 KB (ATmega328P)
EEPROM 1 KB (ATmega328P)
Clock Speed 16 MHz

Raspberry pi/Wifi Dongle/ Power supply:

Raspberry Pi 2 (RPi2) Model B Quad-Core 900 MHz 1 GB RAM
8 GB Micro SD Card (Class 10) - Raspberry Pi Recommended Micro SD Card pre-loaded with NOOBS
CanaKit WiFi Adapter 150 Mbps - Supports Access Point Mode (AP) to allow for WiFi Hotspot hosting
CanaKit 2.5A USB Power Supply with Micro USB Cable and Noise Filter - Specially designed for the Raspberry Pi 2 (UL Listed)

Touch screen:

Wave Share 5 inch resistive touch LCD
800×480 high resolution
Resistive touch control
Supports Raspberry Pi
Supports Banana Pi / Banana Pro, comes with Lubuntu, Raspbian images
Supports BB Black, comes with Angstrom image
For other mini-PCs, driver is required and should be developed by users
Not only for mini-PCs, it can work as a computer monitor just like any other general HDMI screen
HDMI interface for displaying, USB interface for touch control
Back light control to lower power consumption


SUNKEE DS18B20 Temperature Sensor -
Waterproof Digital Thermal Probe Sensor DS18B20DS18B20 Temperature Sensor -
Waterproof Digital Thermal Probe Sensor DS18B20
he high-quality stainless steel pipe encapsulated waterproof moisture-proof anti-rust
Stainless steel housing (6 * 45mm), the leads length of 100cm
Each probe is rigorously tested individually wrapped
3.0V ~ 5.5V power supply
9 to 12 adjustable resolution

I think that is it.



I had miss labeled some of the connection points in my diagram, please see the corrected image

LOL, sorry I made you type all that. I meant:
Make a screenshot of the device list in the web interface.

On the web interface, you have a small LCD screen that will show IDLE/COOLING/HEATING

:laughing: I will, it will be later today though I am away from home.

Thanks again

Both ssr lights are on

Weirdest thing…it is working now. The input signal was flipped (heat ssr was in when cooling)but I switched to not inverted and it’s all good. I don’t know why it’s working now though. Will continue to monitor. You must have some seacret esp or something

Yep, with a bare arduino, non-inverted is the correct setting. The display says ‘waiting to heat’, which means it has a valid sensor and actuator configured, it is just waiting the minimum time to prevent cycling too fast.