Twomes Boiler Monitor Module Firmware

Firmware for the Twomes Boiler Monitor Module.

Table of contents

• General info
• Deploying
• Developing
• Features
• Pairing
• Status
• License
• Credits

General info

This firmware is designed to run on the ESP32 of the Twomes Temperature Monitor hardware, in combination with two DS18b20(Z) temperature sensors in clamps that can be connected the supply water piple (from the boiler to the hydronic radiators) and return water pipes returning from the hydronic radiators to the boiler. We do not expect the end user of the device to be able to distinguish between supply and return water pipes and leave the determination of supply and return to the analysis phase of the data.

The ESP32 reads the temperatures from both sensors and stores them in RTC fast memory, to preserve them during the deep sleep interval between brief moments when the ESP32 needs to be awake for data acquisition. After a series of 20 measurements at fixed time intervals, the ESP32 will send the series of measurements to the Twomes P1 Gateway measurement device using the ESP-NOW protocol.

Via the Twomes P1 Gateway measurement device, the Twomes Boiler Monitor Module sends the following properties to the Twomes server:

Sensor	Property	Unit	Printf format	Measurement interval [h:mm:ss]	Description
DS18b20	boilerTemp1	°C	%.1f	0:00:10	temperature of hydronic supply/return pipe
DS18b20	boilerTemp2	°C	%.1f	0:00:10	temperature of hydronic supply/return pipe

Pairing

After deploying and installation in the home, the Twomes Boiler Monitor Module should be paired as a satellite to the Twomes P1 Gateway measurement device.

Deploying

This section describes how you can deploy binary releases of the firmware, i.e. without changing the source code, without a development environment and without needing to compile the source code.

Prerequisites

To deploy the firmware, in addition to the generic prerequisites for deploying Twomes firmware, you need:

• a 3.3V TTL-USB Serial Port Adapter (e.g. FT232RL, CP210x, etc..), including the cable to connect ths adapter to a free USB port on your computer (a USB to miniUSB cable in the case of a FT232RL);
• You need to place a 3.6V Lithium AA-battery (e.g. SAFT LS14500) in its holder to power the board, as the Twomes Boiler Monitor Module is not powered via the 6 pin programming connector.
• Find a row of 6 holes holes (J1 in the corner of the PCB of the Boiler Monitor Module), find the GND pin (see top of the PCB), align the 6 pins of the serial port adapter such that GND and other pins match; then connect the serial port adapter to your computer and connect the 6 pins of the serial port adapter to the 6 holes on the PCB.

Uploading firmware

• Download the binary release for your device and extract it to a directory of your choice.
• Follow the generic Twomes firmware upload instructions , with the exceptions mentioned below:
  • When you see the beginning of the sequence Connecting ......_____......, press and hold the button labeled GPIO0 (SW2) on the PCB, then briefly press the button labeled RESET (SW1).
  • You should see an indication that the firmware is being written to the device.
  • When the upload is finished, view the serial output with a serial monitor tool like PuTTY or the utility of your IDE (115200 baud). Press RESET (SW1) shortly to make sure the firmware boots.
  • Remove the battery or insert a battery insulating pull tab when you do not plan to use the boiler monitor module immediately, to prevent unnecessary battery drain. In particular, when the temperature sensors are not connected, power consumption is higher.

Developing

This section describes how you can change the source code using a development environment and compile the source code into a binary release of the firmware that can be depoyed, either via the development environment, or via the method described in the section Deploying.

Please see the generic Twomes firmware developing instructions, with the exceptions mentioned below:

• When you see the beginning of the sequence Connecting ......_____......, press and hold the button labeled GPIO0 (SW2) on the PCB, then briefly press the button labeled RESET (SW1).
• You should see an indication that the firmware is being written to the device.

Features

List of features ready and TODOs for future development.

Ready:

• Pairing with a Twomes P1 Gateway measurement device
• Measure temperatures using two DS18b20 sensors
• Deep sleep between data acquisition for ultra-low power consumption
• Send measurement data to Twomes P1 Gateway measurement device using ESP-NOW

To-do:

• Align indication of status and error via LEDs with other measurement devices.

Status

Project is: in Progress.

License

This software is available under the Apache 2.0 license, Copyright 2021 Research group Energy Transition, Windesheim University of Applied Sciences

Credits

This software is a collaborative effort of:

• Sjors Smit · @Shorts1999
• Fredrik-Otto Lautenbag · @Fredrik1997
• Gerwin Buma · @GerwinBuma
• Werner Heetebrij · @Werner-Heetebrij
• Henri ter Hofte · @henriterhofte · Twitter @HeNRGi

Product owner:

• Marco Winkelman · @MarcoW71

We use and gratefully acknowlegde the efforts of the makers of the following source code and libraries:

• Arduino core for the ESP32, by Espressif, licensed under GNU LGPL-2.1
• Library for Dallas/Maxim 1-Wire Chips, by Paul Stoffregen and others, licensed under various licernses
• Arduino Library for Maxim Temperature Integrated Circuits, by Miles Burton, licensed under GNU LGPL-2.1