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Open source thermostat runs openHAB on a Raspberry Pi Zero W

May 13, 2019 — by Eric Brown 4,735 views

MakeOpenStuff is launching a $145 “HestiaPi Touch” smart thermostat that runs a Linux-based openHAB stack on an RPI Zero W along with relays, a 3.5-inch display, and temperature, humidity, and pressure sensors.

In late April, we looked at ionware’s ionware sdk1 home automation controller board, which runs the open source openHAB 2.0 IoT stack on a Raspberry Pi Zero W. Now Athens, Greece based MakeOpenStuff has gone to Crowd Supply to launch a HestiaPi Touch smart thermostat that uses the same combo.

HestiaPi Touch in black and white (left) and internal view
(click images to enlarge)

Both products provide more privacy-driven alternatives to cloud-connected home automation gear such as Google’s Linux-driven Nest products. Last week, Google announced that it was integrating its Nest and Home product lines, bringing Nest branding and features to Google Assistant enabled Home products. The first is a new Google Home Hub successor with a 10-inch touchscreen and a 6.5-megapixel camera called the Google Nest Hub Max.

Google Nest
Hub Max

Google is also dismantling its Works with Nest ecosystem of third-party IoT vendors that offer Nest compatibility. Instead, it is pushing participants toward its much more restrictive Works with Google Assistant program, which will require Google Assistant support.


Google says the change will improve privacy and security since fewer third party companies will have access to personal data. However, since most of the Works with Nest participants are unlikely to quickly overhaul their products to add Google Assistant support, this will limit the amount of compatible smart lights, locks, and other home automation sensors that will work with Nest hubs.

The fully open source HestiaPi Touch should be available with at least 20 optional sensor devices by the time its ships in October or November. Considering its foundation within the openHAB and Raspberry Pi ecosystems, you should be able to integrate many more home automation gizmos.

The Java Virtual Machine (JVM) based openHAB 2.0 is one of the most popular and comprehensive of the many Linux-compatible open source smart home IoT frameworks available. The platform supports open IoT standards like MQTT while also offering compatibility with Google Home and Amazon Alexa devices. Unlike Google Nest and the ecobee4 thermostat, the HestiaPi Touch supports ESP8266-based gizmos, including Sonoff/Tasmota devices.

HestiaPi Touch detail view (left) and major components, with temp sensor at lower right
(click images to enlarge)

The HestiaPi Touch, which we saw on Geeky Gadgets, has 50 days left to reach its $48,000 funding goal on Crowd Supply, with shipments due in October or November. Packages start at $95 without the case, RPi Zero W, or SD card or $110 without the case. There’s also a fully assembled, $145 model.

The hackable device competes directly with the $249 Google Nest Learning Thermostat. Unlike the Nest devices, it does not require a cloud connection thereby ensuring privacy and offering full control to the user.

The Raspberry Pi Zero W supplies the device with a 1GHz, ARM11-based Broadcom BCM2836 SoC, 512MB RAM, 2.4GHz 802.11 b/g/n, and Bluetooth 4.1 with BLE. It also provides a 40-pin GPIO header and micro-USB OTG port. The SBC’s mini-HDMI port, micro-USB power port, and camera connectors “are physically blocked,” says MakeOpenStuff.

HestiaPi Touch terminal block wiring (left) and HVAC connections for US model (24V AV)
(click images to enlarge)

The Zero W is mounted on a mainboard that adds a power supply unit available in both a 24V AC US version with support for HVAC systems with C wire connections and a 100-240V AC EU version. There is also a reset button and 6x screw terminals that can connect to various heating, hot water, and other appliances (see chart above).

The HestiaPi Touch mainboard is further equipped with 4x relays rated for 2A, 110-250V AC. A sensor connector connects to an external module built around the Bosch BME280 sensor. It features -40 to 80°C temperature, 0 to 100 percent humidity, and 300 to 1100 hPa atmospheric pressure sensing. An Ethernet port is optional.

UI for 3.5-inch display
(click image to enlarge)

A separate 3.5-inch resistive, single-point touchscreen connects to the LCD connector on the GPIO array. The screen dominates one side of the 3D-printed, hexagonally shaped, 135 x 120 x 38mm case.

The microSD slot is loaded with a 16GB card with pre-installed openHAB. There are also Android and iOS mobile apps. Schematics and other open source files are already posted.

MakeOpenStuff has so far prototyped wireless sensor modules for CO, CO2, other gases, dust (PM2.5), smoke, temperature, relative humidity, wind speed and direction, water level, water leak, proximity, PIR motion, and magnetic contacts. The company has also developed controlling and monitoring standard relays, power relays, electric motors, water pumps, sirens, lights, and RGB LED strips. Plans call for building a portable remote thermostat, wireless LED strip, and a Modbus compatible version.

Further information

The HestiaPi Touch is available on Crowd Supply through July 2 ranging from $95 (kit) to $145 (pre-assembled with Pi), with shipments due in October or November depending on the package. Shipping is free to the US and $10 elsewhere. More information may be found on the HestiaPi Touch Crowd Supply page, the GitHub page, and MakeOpenStuff’s HestiaPi website.

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