Case Studies

Creating an Ultra Low-Power Bluetooth Device With a Custom PCB and CRYOTIMER

Posted in Circuit Design, Embedded Development & Programming, Product Development


DMC created a fully functional, ultra low-power personal safety IoT device for a client by designing a custom printed circuit board (PCB), implementing Bluetooth-bonding, and using CRYOTIMER. DMC then expanded the original project by creating an automated end-of-line testing system for the device.  


DMC was tasked by a client with extending the battery life of a personal safety device. This wearable device synced to a mobile application over Bluetooth and was controlled by the user through an app. In order to provide proper personal protection, the client needed to manufacture a low-power, low-energy Bluetooth device with a constant mobile connection.

Other products on the market typically need a bulky base station to maintain a charge and connection for extended periods of time. However, DMC bypassed this issue by designing a custom PCB to create an ultra low-power device.

The client’s original design utilized BG script, the proprietary language of Silicon Labs. BG script packaged nicely for easy programming but didn’t give the flexibility and power needed for an ultra low-power scheme. DMC rewrote the firmware in C programming language to allow deep sleep mode and EM4 shut off mode, therefore extending battery life.

DMC further optimized the device by implementing Bluetooth-bonding and using CRYOTIMER. The Bluetooth-bonding process establishes permanent security between devices by storing corresponding encryption information—allowing for fast reconnections in future sessions. The use of CRYOTIMER makes the device to go into very low-power sleep modes, only being woken up for intermittent status reports. Now, the battery is optimized enough to run for the entire lifespan of the device.

Following the battery’s optimization, DMC expanded the original scope of the project to create an end-of-line testing unit. The client’s previous process of checking the Bluetooth connection was entirely manual. To optimize this process, DMC integrated a custom Raspberry Pi into the system.

This unit ran a Linx package and was built with a firmware that allowed the production team to run automatic bond-testing cycles. A single LED indicated whether the device passed or fail, therefore automating the process and reducing testing time. The test even became more accurate with the integration of DMC’s custom Raspberry Pi by removing many sources of human errors.

DMC not only satisfied the original parameters of this project but went above and beyond to serve the client by greatly improving production efficiency and making the device as high quality as possible.  

Learn more about DMC’s product development expertise and contact us to get started on your next project.

Customer Benefits

  • Reliable Bluetooth connection
  • Ultra low-power battery that lasts for the lifespan of the device
  • More efficient and automated product testing
  • Increased testing accuracy