Wired for Success: Redefining Sports & Athletic Training

Electronics used in sport have a slightly different set of requirements from a lot of other products. The device may be moving quickly, worn on the body, exposed to sweat and impacts, and expected to respond fast enough that the athlete does not notice any delay. That puts real constraints on sensing, wireless communication, power, mechanical design and the way data is processed. A device can work perfectly on a bench and still be frustrating to use once someone is actually running, swimming or fencing with it. The product also has to survive a much wider range of conditions than a desk-bound device. Connectors get pulled, enclosures get knocked, cables move and body-worn parts see sweat and repeated flexing. That means the mechanical and electrical design have to be tested together under the way the equipment will actually be used.

Real-time data is particularly useful in training because the feedback can influence what the athlete does next. A motion tracker needs to capture movement quickly enough that the digital representation follows the athlete properly. A scoring system needs to register an event and update lights, sound or haptics with very little delay. Heart-rate, speed and motion data have different bandwidth requirements, but the same principle applies: the sensing and processing chain has to be fast and predictable enough for the application. There is little value in collecting accurate data if it arrives too late to be useful. Accuracy and latency also have to be separated. A sensor can produce very accurate data and still feel wrong if the processing chain adds too much delay. Equally, a very fast system is not useful if the measurement is too noisy to distinguish the movement or event you care about. The requirement normally needs a number for both.

Real-Time Monitoring in Sports

We've developed several sports products at ZTPrototypes, covering wearable motion tracking as well as scoring and feedback systems. One example was our work with SWYMLINE on a Bluetooth motion tracker for swimmers training at home. The aim of the first device was to prove that the user's movement could be measured reliably and fed into the wider videogame system. At that stage we were interested in the core behaviour: could a small wearable capture the right motion, send it with low enough latency, and produce movement in the game that felt believable to the user. That is a much more useful question for an early prototype than trying to make the first unit look like a finished consumer product. We also had to think about how the tracker would be worn, what movement range the sensor would see and how the Bluetooth link behaved while the user was moving rather than sitting beside a laptop. Those are the sorts of details that are hard to infer from a component datasheet and easy to check with a rough prototype.

We started by working through the processor, sensor and wireless requirements and then testing likely parts on off-the-shelf development boards. Power consumption and cost mattered, but the detailed specifications mattered just as much. For the motion sensor, for example, sampling rate and measurement range directly affected how much of the swimmer's movement we could capture and how smoothly that movement could be represented in the game. We tested the major parts independently first, then combined them into the complete signal chain before committing to a custom PCB. That approach made it cheap to swap a sensor or processor if the real measurements did not match what we expected from the datasheet. The off-the-shelf modules were deliberately larger than the final product because they gave us access to signals and made component changes quick. Once the sensor and processor combination had been proven, the custom board could be designed around the real size and power constraints with much less uncertainty.

The proof-of-concept device was then integrated into the wider SWYMLINE system and used to demonstrate the complete experience rather than the electronics in isolation. That gave the client something they could put in front of real users and potential partners, and it produced much better feedback than a specification or render could. The results gave them enough evidence to continue into the next stage of product development and use the working system in partnership discussions.

We've also been developing a new fencing scoring system with body-worn feedback devices. The timing requirements there are different again. A scoring event happens very quickly, several pieces of hardware need to agree on what happened, and visual, audio and haptic feedback need to follow without a delay that changes how the game feels. The sports hall itself also becomes part of the engineering problem because long cables, nearby electronics, lighting systems and moving athletes create a noisy electrical environment. We ended up treating response time, communications reliability and EMC as linked requirements rather than separate parts of the design. The scoring hardware also had to distinguish genuine events from electrical noise and make the decision within the timing window of the sport. We used that requirement to drive the analogue front end, communications and test setup, then verified the system in the real venue because the sports-hall environment was materially noisier than the bench.

Miniaturisation & Smart Textiles

Miniaturisation is useful in sports because every gram and every millimetre can affect whether a device gets in the way. GPS trackers, motion sensors and small cameras can now be integrated into equipment or clothing with relatively little bulk, but making something smaller usually makes the engineering harder. There is less space for the battery, less room around an antenna, less area to spread heat and less freedom to place connectors or controls. For a wearable, we also have to think about where the mass sits on the body and whether the enclosure still feels comfortable during repeated movement. The smallest possible design is not automatically the best one. The useful target is the smallest design that still works reliably and can actually be worn for the activity it was designed around. Battery placement and charging become part of the same packaging exercise. A comfortable location for the cell may be poor for the antenna, and moving the antenna can affect where sensors or buttons fit. These products are usually easier to develop when the enclosure and PCB floor plan are worked on together instead of one being handed to the other at the end.

Smart textiles take this a step further by moving parts of the sensing or interconnection into the fabric itself. Conductive thread and flexible sensor elements can be used to measure things such as muscle activity, temperature or hydration while keeping the electronics distributed across a garment. That creates some interesting possibilities, although it also brings its own practical problems around washing, repeated flexing, connector reliability and how the electronics are removed or protected. As with any wearable technology, these need to be treated as engineering requirements early rather than left until the device has already been miniaturised around an ideal laboratory setup. Connections between textile sections and conventional electronics are often the weak point too. A conductive path that works when a garment is flat on a bench may change resistance when stretched, folded or wet. Those behaviours need repeated-use tests just like a flex PCB or a mechanical joint would.

Our Commitment to Sports Technology

Sports technology has become a useful area of work for us because it combines electronics, firmware, mechanical design and real-world testing very directly. The projects we've worked on have ranged from motion sensing to scoring, audio and haptic feedback, and each one has needed the electronics to disappear into the activity rather than become something the athlete has to manage. We tend to stay involved as those products move through later revisions because the useful engineering work continues after the first demo: shrinking the hardware, improving reliability, testing it in the real environment and getting the design ready for manufacture.