Students and hobbyists build embedded systems that combine sensing, actuation and microcontrollers on solderless breadboards. To help students debug such circuits, experienced teachers apply visual inspection, targeted measurements, and circuit modifications to diagnose and localize the problem(s). However, experienced helpers may not always be available to review student projects in person. To enable remote debugging of circuit problems, we introduce Heimdall, a remote electronics workbench that allows experts to visually inspect a student's circuit; perform measurements; and to re-wire and inject test signals. These interactions are enabled by an actuated inspection camera; an augmented breadboard that enables flexible configuration of row connectivity and measurement/injection lines; and a web-based UI that teachers can use to perform measurements through interaction with the captured images. We demonstrate that common issues arising in embedded electronics classes can be successfully diagnosed remotely and report on preliminary user feedback from teaching assistants who frequently debug circuits.

The rise in prevalence of Internet of Things (IoT) technologies has encouraged more people to prototype and build custom internet connected devices based on low power microcontrollers. While well-developed tools exist for debugging network communication for desktop and web applications, it can be difficult for developers of networked embedded systems to figure out why their network code is failing due to the limited output affordances of embedded devices. This paper presents WiFröst, a new approach for debugging these systems using instrumentation that spans from the device itself, to its communication API, to the wireless router and back-end server. WiFröst automatically collects this data, displays it in a web-based visualization, and highlights likely issues with an extensible suite of checks based on analysis of recorded execution traces.

The Maker movement has encouraged more people to start working with electronics and embedded processors. A key challenge in developing and debugging custom embedded systems is understanding their behavior, particularly at the boundary between hardware and software. Existing tools such as step debuggers and logic analyzers only focus on software or hardware, respectively. This paper presents a new development environment designed to illuminate the boundary between embedded code and circuits. Bifröst automatically instruments and captures the progress of the user's code, variable values, and the electrical and bus activity occurring at the interface between the processor and the circuit it operates in. This data is displayed in a linked visualization that allows navigation through time and program execution, enabling comparisons between variables in code and signals in circuits. Automatic checks can detect low-level hardware configuration and protocol issues, while user-authored checks can test particular application semantics. In an exploratory study with ten participants, we investigated how Bifröst influences debugging workflows.