mgonzal1/drmem

Full source tree for the DrMem control system

A small, capable control system for the hobbyist

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The DrMem Project strives to be a complete, easy-to-use control system for home automation. Like the Arduino and RaspberryPi communities, this project is aimed at the hobbyist that likes to tinker and build systems. Although commercial products will be supported, nothing prevents you from incorporating and controlling your own custom hardware.

DrMem has been developed with the following design goals:

• Reliability. Excepting hardware failures, this control system should provide 24/7 service in controlling and monitoring its devices. Like any project of this type, careful design and extensive testing will help prevent issues. However, DrMem will also be written in the Rust programming language which provides strong compile-time checks which eliminate whole classes of bugs that occur in other languages. This project is an experiment in writing mission-critical code in Rust.

• Efficiency. Because we're using Rust, we have a systems programming language which generates optimal code and reduces CPU usage. Less CPU means reduced power consumption and less latency in responding to hardware inputs. In this project, we're also using the tokio async scheduler which means tasks will get distributed across all cores of the system, further reducing latencies (or providing more scalability.)

• Simplicity. DrMem is targeted for small installations so we want to minimize the number services that need to be managed. The drmemd executable, along with a configuration file that defines your location's set of devices, is all you need.

• Accessibility. Although DrMem is capable running in the background with no user interaction, it is useful to have an interface that applications can use to provide dashboards, etc. for viewing and controlling DrMem devices. This is provided by a built-in HTTP server hosting a gRPC interface.

Other Control System / Home Automation Projects

DrMem is a young project. If you're looking for more complete solutions that are available now, here's a few options:

• EPICS is a professional control system used by particle accelerators and observatories around the world.
• Mister House is a home automation system, written in Perl, that has been around for decades.
• Home Assistant is a nice-looking, well-polished, home automation system.
• Many devices can also be controlled by Google's Home app or Apple's Home app

But be sure to check back occasionally as drmem matures!

Preparation

The core service used in this control system is Redis which is light-weight, fast and has the data management features needed for a control system: device information and time-series storage of device readings.

redis servers support multiple databases. The default database is number 0 and is what DrMem uses. For testing, other database numbers can be used which isolates possibly buggy, development code from the "operational" database.

Before setting up DrMem, you'll need to have a running instance of redis. The author configured an instance on a RaspberryPi to only listen on 127.0.0.1. If the control system grows beyond one node, redis can be configured to listen on the local network. redis is an in-memory database, so the author configured it to periodically dump the database on a NAS over NFS.

Building

DrMem is written in Rust using the excellent tokio async scheduler module. To build it, you'll need a Rust installation.

NOTE: This project is in a very, very early state. Eventually I want users to specify which drivers to use in drmem.conf. Right now every driver gets built and run.

Check out the source, run cargo build --release, and relax; this takes a half hour to build on my RPi 3+. On server boxes, it'll build much faster.

Developers can run cargo build to create the debug version (found in target/debug/drmemd).

Colophon

The name of this project, DrMem, is a shortened version of "Doctor Memory" -- a character from Firesign Theatre's comedy album, "We're All Bozos on this Bus". Doctor Memory is the marginally intelligent, easily confused AI that operates behind the scenes of the Future Fair.

Although this project strives to be much more reliable than this fictional character, I wanted to pay homage to Firesign Theatre's early vision of a powerful control system.

... this is Worker speaking. Hello.