Cerebra is a charity that develops innovative products to help children with brain conditions participate in everyday activities and sport. The charity had previously developed a Mk1 prototype of a sensory tag rugby system; however, the original electronics were not functional.

The brief was to redesign the electronics and develop a robust wearable tag rugby system. The belt needed to provide clear multi-sensory feedback through high-visibility LEDs, an audible buzzer and haptic vibration, allowing players with different sensory needs to immediately recognise when they had been tagged.

The system also required low-power RF communication with a pitch-side receiver, which announces the colour of the tagged team to assist referees, officials and spectators.

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  Schematics: Designed full-system MCU, BMS, and tag sensing in Altium.

• RF Design: Integrated 433MHz module with Pi matching network.
• Power Logic: Gated peripherals to eliminate idle current draw.
• Sensory UI: Implemented LED, buzzer, and haptic feedback.
• Sensor R&D: Invented low-cost, low-power tag-colour sensor.
• Bring-Up: Executed board bring-up, debugging, and RF range testing.
• Thermal Analysis: Profiled peak operational thermal behaviour.
• DFM / Spatial: Fixed 3rd-party CAD interference errors in Altium.
• Client Lead: De-risked technical decisions and managed delivery.

Review of the original prototype identified several areas where the electronics could be significantly simplified. One example was the replacement of a complex NFC-based tag detection system with a single analogue Hall-effect sensor. Using the magnets already present in the mechanical tag attachment, the system could identify up to four team colours from magnetic field polarity and magnitude using a single MCU input.

Power consumption was another key consideration. A digital Hall sensor and hardware load switch were used to isolate high-current peripherals—including the LEDs, buzzer and haptic motor—when they were not required. This reduced standby current and helped maximise battery life from the compact rechargeable cell.

For pitch-side telemetry, an off-the-shelf 433 MHz RF module was integrated with a custom matching network and flexible antenna options. Addressable RGB LEDs were also selected to simplify PCB routing and firmware control.

The final electronics had to fit within a compact curved enclosure with tight Z-height constraints. A densely populated double-sided PCB was developed with consideration for charging, thermal performance and mechanical clearances. A dedicated 3D spatial review in Altium identified screw-boss and pogo-pin clearance issues before manufacture, reducing the risk of mechanical rework during assembly.

Laboratory bring-up verified the power rails, charging circuitry and core hardware functions before the prototypes were released to the software team for firmware integration.

Thermal testing was also carried out to assess the charging circuit and PCB heat dissipation. The charging IC reached a measured peak temperature of approximately 42°C under the tested conditions.

Formal EMC compliance testing was outside the scope of this development phase.

Following bench validation, the sensory belts were deployed in field trials with the Leeds Rhinos Foundation and Saracens.

The trials provided an opportunity to evaluate the system under real playing conditions, including the mechanical durability of the wearable enclosure, visibility of the LED feedback, operation of the haptic and audible alerts, RF communication and battery endurance.

The hardware performed successfully throughout the sessions and the battery capacity was sufficient for the duration of the trials.

Client feedback following the sessions was positive:

“Positive testing with the Leeds Rhinos Foundation and Saracens. The participants really loved the concept, and we’ve learned a lot from the sessions.”