Wwe were part of the product lifetime from the beginning and collaborated with our client on how to improve it and where to focus our efforts.

We got to maximize BLE Throughput of the system when things got cluttered with features and requirements and peripherals.

As a multiple moving part system the debugging processes were intricate. Sometimes requiring us to massage some inner connections; 

• like short-circuiting the LEDs on a faulty board in order to use that output pin as a UART, which we were missing

Conclusions

For this project I found great satisfaction in crafting a detailed mind-map tracing from all hardware components to the most lower-level firmware elements. 

Guaranteeing an accurate and effective data-gathering stream received on the smartphone was imperative (iOS and Android, Windows/Mac too, with Python's BLEak).

• The collar included GPS, LoRa and Bluetooth communications.

• My tasks included having the drivers ported, tested and functioning on the newer FW and HW platform.

• Adding BLE OTA DFU as a feature.

• Using GitHub Actions as CI/CD tasks to build system, generate binaries as artifacts and uploading those sync'ing the DB.

^ Still image on the spied monitor.

Resulting spy attack >

We implemented a screen resolution inference GNU Radio module for the SDR attacker system. It was key to apply the fft algorithm in order to make the compute plausible.

We improved the sampling error correction GNU Radio module so that less performance is required to run the DSP algorithm. In depth, we swapped the existing time-domain approach for a frequency-domain calculation of the auto-correlation of the spied signal using the Discrete Fourier Transform of the VGA or HDMI stream.  

This project was a challenging out-of-the-box and hacky experience as a whole. 

It also brought us out of our comfort zone in two main aspects, on the social day-to-day team management side of things; handling the frustrations and competences of three very different engineering students, and on the technical parts; having us get used to RF circuits, signals, C++ and wireless channels, and the noise that follows those, which were all topics out of our areas of expertise. 

Coming from a very analog hardware and imperative programming oriented electronics engineering career, it was a lot to take in and took a lot of massage to make things happen.

• Development focused on highly performant code implementations. 

• Reactiveness of the MCU code is very fast.

• Debugging includes pre-silicon emulation tools and traces.

• Time scales for events that we commit to are pinpointed to the microsecond, or tenths or hundreds of ns.

• Logic analyzer debugging tools.

• Hardware emulation tools. 

• As state-of-the-art techniques.

• Clock gating, power gating, voltage and frequency scaling techniques. Digital voltage regulation. The hardware is just top notch.

• Graphics pipeline understanding, - the different system states.