2025 One Hertz Challenge: Educational Tool Becomes 10 Stopwatches

In a remarkable hack, [Ray Burne] has transformed the Smart Response PE digital handheld device into a versatile stopwatch that can track up to ten separate timers. This innovative project, submitted to the 2025 One Hertz Challenge, showcases the potential of repurposing educational tools for everyday use.

The Smart Response PE device, with its candybar cellphone design and Texas Instruments CC2533 microcontroller, was initially intended for classroom use. However, [Ray] saw an opportunity to breathe new life into this hardware, leveraging Github user [serisman]'s readily available development tools to create a custom programming experience.

By modifying the device's programming, [Ray] enabled it to function as a simple stopwatch – but not just one. The device can now track ten individual timers, each accessible through its numeric keypad and control buttons. Pressing a number from 0 to 9 activates the corresponding timer, which begins ticking away on the LCD screen.

To provide a temporary laptime reading, [Ray] added the ability to pause the screen updates by pressing the enter key. Furthermore, a Home button resets the screen and all timers at once, making it easier to manage multiple stopwatches simultaneously.

"It's a fun build," [Ray] notes, "and one that could prove useful for anyone frequently requiring time for ten or more items." Whether measuring cooking times for eggs or tracking athletic events with multiple participants, this stopwatch solution offers an efficient and convenient alternative to juggling multiple traditional stopwatches.

For those interested in hacking their own obscure hardware finds, [Ray] provides valuable resources on his project page. The documentation includes tips on how to add a real power switch to the device and modify the programming pins for easy access. With these instructions, makers can replicate this clever project and unlock the full potential of their Smart Response PE devices.

If you're working on your own creative projects or have discovered another fascinating hardware find, don't hesitate to share it with our tipsline! We'd love to hear about your innovative ideas and experiences.