Practical Engineering Notes on Rusty Eddy

Software is Hard

Fri, 22 May 2026 00:00:00 +0000

A section opener explaining why software projects drift and how use cases, Kanban, testing, review, and release discipline make them predictable.

OttO: A Go-Based IoT Edge Gateway Architecture

Thu, 13 Jan 2022 00:00:00 +0000

A practical architecture overview of OttO, the Go-based IoT edge gateway used by the Organic Gardener project.

Use Cases

Fri, 27 Sep 2024 00:00:00 +0000

Why This Matters

Use cases are the first concrete step after recognizing that software is hard. Before writing a single line of code, we need to understand what we are building — and more importantly, why someone would use it. Use cases give us that foundation.

A use case is a single, focused story that describes one way a user achieves a specific goal with the system. Keep them in plain language, from the user’s point of view, with no technical jargon. A good use case has a clear success condition: you can observe or measure when it worked.

Use Cases to Tasks

Thu, 26 Dec 2024 00:00:00 +0000

A use case describes value from the user’s point of view. A task describes a piece of work a developer can finish. Confusing those two is one of the fastest ways to turn a software plan into a vague backlog.

Why This Matters

Use cases are useful only if they turn into work the team can plan, build, and verify. Translating them into small tasks keeps the connection between user value and implementation visible.

Organizing Software Projects with Kanban

Fri, 22 May 2026 00:00:00 +0000

A practical guide to using Kanban cards, WIP limits, task sizing, and exit criteria to keep software projects visible and predictable.

Version Control Systems

Fri, 22 May 2026 00:00:00 +0000

A practical guide to using Git history, branches, pull requests, and tags as the permanent record of a software project.

ESP32 Collection Station Architecture for IoT Sensor Networks

Thu, 13 Jan 2022 00:00:00 +0000

A device-side architecture note for ESP32 collection stations in the Organic Gardener IoT system.

Test Driven Software Development

Fri, 22 May 2026 00:00:00 +0000

A practical guide to test-driven development and the role of unit, integration, system, and acceptance tests in a reliable release process.

Peer Reviews

Thu, 21 May 2026 00:00:00 +0000

A practical guide to code review: what authors should prepare, what reviewers should check, and how pull requests fit into release quality.

Wireframes and Storyboards

Thu, 21 May 2026 00:00:00 +0000

A practical guide to using storyboards for user flows and wireframes for screen decisions before implementation begins.

Release Process

Thu, 21 May 2026 00:00:00 +0000

A practical release process for turning reviewed and tested code into versioned, recoverable software artifacts.

Panasonic Avionics

Fri, 01 Dec 2023 00:00:00 +0000

Member of Technical Staff working on connected systems at aviation scale. The work combines production software engineering, networked systems, multicast behavior, operational reliability, and coordination across hardware, platform, and application teams.

The role builds on my background in multicast routing, embedded systems, Linux, and distributed software: making connected systems understandable, testable, and maintainable when they have to operate in real environments.

Sugo Music Dashboard

Wed, 27 Jan 2021 00:00:00 +0000

Sugo Music is an online Music publishing platform for Artists by artists. It was my responsibility to manage the software process, build and test the backend and manage the front-end development in React.

Go, React, REST API, HTTP, HTML, JavaScript, Webapp, fullstack

University of Southern California ~ MSCS

Tue, 02 Jan 1996 00:00:00 +0000

Sahara Networks

Wed, 27 Jan 2021 00:00:00 +0000

Sahara Networks is building something truly unique, connecting microcontrollers and IoT devices across the network allowing virtual circuits to be created. I help design, develop and lead the design and implementation of the network protocol that delivers high speed digital I/O signals across a “device network”.

Backend, C/C++, nodejs, TCP/IP and Raspberry Pi

Radian Laser

Mon, 01 Jul 2019 00:00:00 +0000

Radian is a small, fast moving startup that sells Laser Engravers and Cutters. I manage five software projects, including two Web Applications for the control and calibration of the Laser system. I am also responsible for the successful delivery and maintenance of the products Firmware and Fleet Management system.

C/C++, Go & Python, embedded systems and microservices.

Cloud Trek

Sat, 01 Apr 2017 00:00:00 +0000

Alchemy Networks is an independently owned service provider. I automated the provisioning of their Private Cloud Service offering. I was an individual contributor on this project. I collaborated with another developer.

Ansible, Linux, Python, Websockets, Networking

DirecTV / AT&T

Thu, 01 Dec 2016 00:00:00 +0000

I was hired by DirecTV (and subsequently AT&T) to help lead the new Software Defined Networking (SDN) team. We were tasked with replacing the companies aging production Video Distribution Network with a new modernized design. Project goals included:

Replace aged network with modern SDN solution
Solution to incrementally replace existing production network
Development would build on industry standard OpenSource solutions
Had to be Reliable and Scalable
Linux, OpenFlow, Java and Python

Sierra Hydrographics

Sat, 02 Jan 2010 00:00:00 +0000

Led the design and development of automated data collection for hydrological gauging stations. Data is gathered by pulling data from line of sight telemetry radios and NOAA/LRGS satellite ground stations. Data is fed to timeseries server for hydrological calculations and alert monitoring.

Timeseries database, C/C++, PHP, Python and Java.

Green Hills Software

Thu, 02 Jan 2020 00:00:00 +0000

I worked on a small team that added multicast forwarding to the Integrity RTOS kernel. Modified multicast routing daemon to run on same operating system allowing the product to serve as the foundation for a military grade network switch/router. Added IPv6 Neighbor Discovery to the suite of routing protocols.

C/C++ and Network Routing Protocols; Real Time OS.

The IMS Company

Fri, 21 Sep 2018 00:00:00 +0000

Led a project to replicate entertainment media (music, video and games) from a single media source to hundreds of inflight entertainment units with minimal redundancy. Contributed to the design and development of an inflight entertainment server.

Perl, Python, C/C++ and Java

Cisco Systems

Wed, 01 Feb 2006 00:00:00 +0000

Original member of the Multicast Routing team. Team of 12 responsible for the design, implementation and testing the complete suite of Multicast Routing protocols for the Cisco Carrier Routing System (CRS). Worked this project from early design through product launch into maintenance.

Computer Networks, Multicast Routing, C/C++, Real Time, Distributed Systems

California State University, Long Beach

Tue, 02 Jan 1996 00:00:00 +0000

USC ~ ISI

Thu, 20 Sep 2018 00:00:00 +0000

Led the effort to add IGMP/PIM and Multicast Routing Information Base (MRIB) to the Open Source GateD suite of routing protocols. Mentored graduate students and others that would eventually become prominent members of the computer networking community.

Retix

Tue, 01 Aug 1995 00:00:00 +0000

Promoted to lead the team of 6 engineers that developed and automated test plans for L2 switches, OSPF, RIP and BGP

Implemented an automated test framework and led junior engineers in developing the automated test suites. C; C++; Perl; TCL
Provided 3rd level customer support, serious customer problems that could not be resolved by customer support or field engineers became my teams responsibility to diagnose and determine solutions and workarounds was required.

Rockwell, Intl. Space Systems Division

Mon, 03 Jan 1994 00:00:00 +0000

Led a team of 5 Sysadmins responsible for the use and well being of Engineering Departments 300+ UNIX workstations, servers (Sun, HP, DEC) and network.

On a team that Developed a Real Time OS that was embedded in a variety of space and military projects.

California State University ~ Chancelors Office

Tue, 01 Aug 1995 00:00:00 +0000

I was hired to install and manage the departments first AT&T Unix Mini-computers, UUNET connection and write a bulletin board system for California State Educators.

Exposing a Go App as Claude MCP Tools

Fri, 22 May 2026 00:00:00 +0000

The Model Context Protocol (MCP) lets Claude call external tools defined by your application. Instead of pasting data into a chat window or writing one-off scripts to query your system, you define tools with typed schemas, start an MCP server, and Claude can call them directly — in Claude Code, Claude Desktop, or any MCP-compatible client.

The Trader project uses this to expose its Forex trading engine as Claude tools: query your OANDA account, review open trades, run a backtest against historical data, and — when explicitly enabled — place or close orders.

Fixed-Point Numeric Types in Go Financial Software

Fri, 22 May 2026 00:00:00 +0000

A practical guide to fixed-point arithmetic in Go for prices, money, pips, API boundaries, and trading-system correctness.

The Strategy Pattern in a Backtesting Engine

Fri, 22 May 2026 00:00:00 +0000

A practical design for keeping trading strategy logic portable across backtests and live execution by returning plans instead of touching brokers directly.

The Five Layers of a Practical IoT System

Sat, 15 Nov 2025 00:00:00 +0000

A practical five-layer model for IoT architecture, grounded in the OttO edge runtime and the Gardener reference application.

Building an IoT Device Abstraction Layer in Go

Sun, 02 Nov 2025 00:00:00 +0000

IoT applications get hard to maintain when hardware code and application logic are tangled together. A prototype can read one GPIO pin or one I2C sensor directly. A real system has sensors, actuators, timing loops, message publishing, local storage, APIs, dashboards, and failures that happen at the edge.

The useful boundary is a device abstraction layer: hardware-specific drivers stay below it, application logic stays above it, and the two communicate through small interfaces.

Adafruit Soil Moisture Sensor Notes for IoT Projects

Wed, 13 Mar 2024 00:00:00 +0000

Adafruit Soil Moisture Sensor Notes for IoT Projects

Notes on using the Adafruit STEMMA soil moisture sensor after unreliable results from cheap capacitive sensors in an ESP32 garden project.

https://github.com/rustyeddy/iotesp

Cheap capacitive soil moisture sensors are attractive for garden automation because they are inexpensive and easy to find. In practice, the ones I tried were inconsistent enough that they became a distraction from the larger system design — and that is the whole point of this note. When the sensor is one small part of a larger system (collection stations, an edge gateway, MQTT data flow, REST APIs, and a dashboard), a slightly more expensive sensor that behaves predictably is cheaper than spending days debugging noisy readings.

Soil Moisture Sensors for IoT Garden Projects

Thu, 15 Feb 2024 00:00:00 +0000

Practical notes on soil moisture sensor reliability, calibration, protection, and sensor choice for a self-watering garden project.

IoT System Architecture (Device to Cloud)

Fri, 13 Jan 2023 00:00:00 +0000

This page is a diagram-first overview of the IoT architecture used throughout the projects on this site. It is for engineers who need to decide where device logic ends, where edge coordination begins, and how telemetry, control, APIs, storage, and user interfaces fit together.

The goal is not to present a single correct design. The goal is to show a reasonable baseline that can grow beyond demos without locking the system to one board, one sensor, one database, or one user interface.

Self-Watering Garden: An IoT Architecture Case Study

Wed, 25 May 2022 00:00:00 +0000

A practical case study showing how a self-watering garden can be designed as an IoT system with clear device, gateway, API, and dashboard boundaries.

Using Go timers for MQTT testing

Mon, 02 May 2022 00:00:00 +0000

This article uses a Go timer and the Go select statement to test our MQTT publish and subscribe in a single simple test statement. A quick note on the go testing package: it is much like the JUnit where tests using a particular naming convention TestXXX(t *testing.T) {} will be run automatically with easy to reports having been generated.

The Problem

The following code snippet is directly from the IoTe edge gateway project. One of the primary features of IoTe is the ability to send and receive MQTT messages.

REST APIs for IoT Gateways: Control, Configuration, and Telemetry Access

Wed, 30 Mar 2022 00:00:00 +0000

A practical REST API design note for IoT gateways, covering Go handlers, JSON responses, endpoint boundaries, testing, and common API pitfalls.

Adding MQTT to the IoT Gateway

Tue, 29 Mar 2022 00:00:00 +0000

A practical MQTT implementation note for the OttO IoT gateway, covering topic design, subscriptions, callbacks, testing, and memory boundaries.

Go timers to remove stale sensor stations

Tue, 03 Nov 2020 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

This article introduces Go timers as the mechanism the IoTa gateway uses to identify stale IoT stations. Modifying the Station with with a new Go timestamp field will allow IoTe to determine how long it has been since the last time it has heard from a given Station.

If the last refresh time for a particular station has been longer than the timeout period the Station will be marked as stale.

Career Summary

Thu, 02 Jan 2020 00:00:00 +0000

I am a software engineer focused on networking, embedded systems, IoT, Go, and distributed systems. I build production software for connected devices, automation, networked services, and systems that need to keep working outside a lab.

My background includes aerospace software, multicast routing, embedded systems, Linux automation, consulting, and connected products at scale. I am strongest where software architecture meets real hardware, real networks, and small teams that need practical delivery.

Skills and Interests

Thu, 02 Jan 2020 00:00:00 +0000

Go, C/C++, Python and JavaScript (and many others..)
Computer Networks, Multicast Video Distribution
Distributed systems and realtime communications
DevOps, cloud automation and continuous delivery
Fullstack software development, reactive front-ends with VueJS
MicroServices: REST APIs, Websockets, etc.
Linux Systems and OpenSource Software

Why Choose Go for Your Project?

Sun, 22 Sep 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

Go is simple

Go is easy to learn to program with and it is free! Go is much easier to maintain and deploy than Java.

Go does not have weird virtual environments of Python or npm, gulp, grunt, yarn, webpack (what’s next?) convoluted and complex build environments.

Go is Fast

It smokes most other languages, except the grand mother of Unix programming C. The Go programming language is almost as fast (performant geeky folks like to say) as C.

Red Eye Video Server

Fri, 24 May 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

The Red Eye project is a service definition rapper around inexpensive cameras attached to inexpesive micro-controllers that take pretty good video.

The video streams are built using the GStreamer library. The camera native capabilities are used to extract as high quailty, realtime images possible.

The video streams will be consumed by one or more sinks, including but not limited to Files, cloud storage, High Def Display and Computer Vision libraries.

Skid Steering

Wed, 15 May 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

Skid steering basics

Based on fixed direction wheels[1] or tracks
There are two groups or sides of wheels: left and right
All wheels in a group MUST always point in the same direction
All wheels in a group MUST always rotate at the same rate
Direction is determined by the speed of the two wheel groups
- To move straight all motors rotate at the same rate
- Forward and Reverse are determined by positive and negative values
- Turning is achieved by varying the throttle on the right and left

Example

The Skidder class has the following API, as you can see all of the movements we desire can be accomplished with a single API call skidder.set_throttle(left_throttle, right_throttle), does not get much simpler than this!

Raspberry Pi Motor Control Software

Tue, 14 May 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

This software adds a Skid Steer motor control software to the Raspberry Pi Device Server device server. RPID adds motor controls accessible via both MQTT and REST APIs, as well as directly with the Skidder python library.

MQTT for Controller Communication

Fri, 03 May 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

The MQTT message bus is a simple but critical element of our MBR software design. MQTT provides what is known as a publish/subscribe or pubsub communications model. This model of machine to machine communication has some attractive benefits for realtime driving algorithms that we will discuss in this post.

Streaming Video is Complicated

Mon, 29 Apr 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

I need to stream live video from a moving vehicle with a connected camera and a possibly connected Wi-Fi network.

Live High Resolution Video

Video will stream from the vehicle to be picked up by video consumers and processed as required. Examples of consumers are Live Video Display on our (Webapp), OpenCV for vision algorithms.

Streaming Video Tools

Tue, 23 Apr 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

The grandparents of streaming video, and snapshots, read, writing and transcoding video and single frame images are ffmpeg, vlc and gstreamer.

Other platforms, such as the wildly cool and inexpensive Raspberry Pi and attached CSI Camera (Raspberry Pi Camera) have thier own set of utilities: like raspivid. Or the NVidia Nano with it’s gst-streamer plugins and nvgst-capture/nvgst-playback utilies.

TLV: The Type-Length-Value Protocol

Wed, 17 Apr 2019 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

TLV is a very simple communication protocol that can be used to send messages around a complex, distributed system.

Streaming Live Video on a Local LAN vs. the Internet

Sun, 23 Dec 2018 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

differences in local vs. internet and streaming video
live stream vs. video on demand
what does real time mean?
what to do with late packets?
UDP vs. TCP in the local network
RTP and UDP
RTP and RTCP
RTP and RTSP
RTP and Multicast
Tools used

RTSP is a good option for streaming video in a local setup up, where minimal delay is the highest priority. However, RTSP does not typically do very well over the Internet due to the nature of RTP/UDP.

Publications

Fri, 21 Sep 2018 00:00:00 +0000

Ramesh Govindan, et el. “An Architecture for Stable, Analyzable Internet Routing”, IEEE Network Magazine, Jan-Feb 1999.

Rusty Eddy, Ramesh Govindan, “Testing Protocol Implementations with pkt”, Networld+Interop 99 Engineers Conference Proceedings, June 1999

Rusty Eddy, “Emulating Multicast Routing Protocols in a Software Defined Networking (SDN) Controller”, AT&T 2016 Software Symposium

Rusty Eddy, “Testing Multicast SDN Networks in a Container”, AT&T 2016 Software Symposium

Inexpensive Motor Controllers for Arduino and Raspberry Pi

Wed, 22 Aug 2018 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

I prefer to use an Arduino with a Motor Controller over say a Raspberry Pi with a motor-controller. I believe the Arduino has better support for dedicated Real-time software vs. the Raspberry Pi and as a superior platform for general computing including running Control Software. This is how we do it on the West side …

Control System Design

Sat, 05 May 2018 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

Early in the process of building the first set of mobile robots I discovered that I was not going to settle on a single micro controller.

The first two obvious choices being the Arduino or Raspberry Pi, for which I tried both with a modest level of success. I quickly realized that I would not be providing my sole focus on either platform, neither was sufficient for my grand plans for a number of reasons.

IP Multicast Basics

Sat, 03 Feb 2018 00:00:00 +0000

Older project note. Kept for historical context; some implementation details may no longer reflect my current recommendations.

IP Multicast addresses

The typical IP addresses used by computers networking today are known as unicast addresses, meaning that every unicast address as a single (physical or logical) end point.

Most all computer networking is point to point between two specific IP addresses, you name it: web browsing, email exchange, transfer files and so much more.