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Sep 11, 2023

Steve Rodgers Gives Honeywell Alarm Systems a Home Assistant Upgrade with a Drop

Electronics engineer Steve Rodgers has designed a drop-in replacement for old Honeywell or DSC alarm panel boards, built around an Espressif ESP32 and using ESPHome to add existing alarm systems to

Electronics engineer Steve Rodgers has designed a drop-in replacement for old Honeywell or DSC alarm panel boards, built around an Espressif ESP32 and using ESPHome to add existing alarm systems to Home Assistant setups — no cloud service required.

"I had a Honeywell alarm panel and an EyezOn EnvisaLink to interface with HomeAssistant, but it depended on the cloud, and the Honeywell panel didn't transmit information to the EyezOn board when a sensor was restored to the non-faulted state," Rodgers explains. "[So] I designed this board to completely replace a Honeywell Vista 20 alarm panel."

The eight-zone alarm panel mimics most, but not all, of the features of the original, barring only support for arming and disarming via keypad and central station monitoring. In exchange, it provides an Espressif ESP32 microcontroller designed to host the ESPHome firmware and integrate into a Home Assistant or compatible home automation system.

The panel includes a built-in charger for an original lead-acid battery backup, eight supervised zones expandable to 16, a 12V siren output, integrated temperature sensor, full fuse protection, and connectors for zone expansion and access to the I2C bus for additional sensors. Wired sensors connected to the panel show up in Home Assistant as binary sensors, Rodgers explains, ready for triggering alerts or other automations.

Rodgers is selling the panel as a mostly-assembled kit — needing two switches adding by the end user, as a means of swerving the need for FCC certification as a complete device — via his Tindie store for $159, though it comes with a warning: "The controller is shipped without firmware which can connect to your Wi-Fi network," Rodgers explains. "It will require some firmware programming and electrical knowledge to successfully implement."

Home Assistant YAML configuration files for the board are available on GitHub, for both the stock eight-zone board and an expanded 16-zone version.