When hackers get together, it's not always for nefarious reasons. Good things can happen, especially when those hackers are part of the revered Chaos Computer Club, Europe's largest association of hackers.
Every four years, Chaos Computer Club Germany hosts Chaos Communication Camp (CCCamp), drawing roughly 6,000 hackers from around the world to Berlin for five days of talks, workshops, and other activities dedicated to electronics, privacy, data protection and data security, and freedom of information. With hackers being the creative bunch that they are, it's no surprise that the CCCamp badge is so popular among attendees eager to show off their firmware alterations and hacks. For each event, a team of hardware, software, and firmware engineers develops a function-rich event badge that also serves as a longer term reference design for evaluation of the components inside. Ole Dreessen, a field applications engineer at Maxim by day, is a longtime member of the Chaos Computer Club and a seasoned veteran of developing unique CCCamp badges. This year, he helped create a wrist-worn badge that is packed with health-monitoring technology.
Called card10, the badge features an array of environmental and health sensors, including electrocardiogram (ECG), temperature, accelerometer, gyroscope, and barometer. Ole served as the main system architect, performing most of the hardware design. He noted that each time, the badge design team aims to highlight a specific type of technology. For instance, in 2015, the badge was a software-defined radio reference design, as the team felt it was important to heighten awareness of this technology. "This year's technology driver was medical and health, so we decided to do a wristband device," Ole said.
Ole Dreessen shows off card10, a wearable reference design that also served as the event badge for this year's CCCamp in Germany.
ECG and PPG Sensors Inside
Vendors, including Maxim, contributed parts for the badge. Maxim components inside include:
- MAX30001 ultra-low-power, single-channel integrated biopotential and bioimpedance analog front-end (AFE). The IC provides ECG waveforms, heart rate and pacemaker edge detection, and a single bioimpedance channel that can measure respiration.
- MAX86150 integrated photoplethysmogram (PPG) and ECG bio-sensor module for mobile health applications
- MAX77651 ultra-low-power power management IC with three-output single inductor, multiple output (SIMO) technology and power path charger for wearables
- MAX32666 low-power Arm
Cortex M4 with floating-point unit- (FPU-) based microcontroller with Bluetooth 5 for wearables - MAX3202E low-capacitance two-channel, ±15kV ESD protection diode array for high-speed data interfaces
Card10 has demonstrated the ability to measure the heart's electrical activity, heart-beat interval, breathing frequency, and even eye movement. Since card10 is an open-source project, engineers are encouraged to download the design documents (source code, schematics, layout, etc.) and use MicroPython to develop their own applications for the design. The board itself is intended to last more than five years. Ole notes that the design is meant to be repurposed or reimagined into something else. Resources are available on the card10 wiki page.
"At the camp, folks started to develop things like algorithms, making themselves familiar with MicroPython very easily. I saw in almost every single face a smile. So this technology will live for quarters, maybe years, after that event, helping people to develop things and go deeper into that technology. The feedback was really positive," said Ole.
Fueling a Passion for Reverse-Engineering
For Ole, this "extracurricular" project was an opportunity to further flex his engineering muscles. Outside of work, his interests include working on various engineering projects and satisfying his interest in reverse-engineering things. For the upcoming Chaos Communication Congress this winter, he is planning to enhance card10 by replacing the top board and including a larger display. This would open the door to applications where a wrist-based device would be too small. So far, CCCamp attendees have written more than 650 apps for card10. Meanwhile, Ole is watching out for any new use cases that may emerge, noting, "It's always about hacking and developing code for those parts as well as applications."
