A few months ago, Element14 and Texas Instruments Challenged us to create a wearable with the MSP432 with the theme of keeping us safe. I proposed to create a wearable jacket that could relay important information and sensor data from the cloud or station to the wearable and vice-versa. My initial proposal and plan are available at Safe & Sound - Safety Jacket for the Tolling Industry #1: Introduction to Project
My initial design had a Raspberry Pi at the data sink however as I started work with the parts, my understanding of their capabilities evolved and the design with it. This is the best part of a design challenge allowing us to explore possibilities while gaining new skills.
My final design submission consists of a functional jacket that has the MSP432 running multiple tasks which allows for future expansion in functionality and a singular BLE connection for communication which reduces the complexity and power consumed. The wearable display accompanying the design is self sustaining via solar power harvesting while Qi Charging and a removable power source adds a novelty feature to the project.
All the code, STL files for the 3D printed Enclosures along with a few tutorials are available on GitHub and Pinshape free of cost for download. We are thankful to Texas Instruments and Element 14 for this opportunity and their support.
A sequence of blogs is available at Safe and Sound Blogs for the Companion Jacket.
The Design and Build
The final design is shown below which consists of four modules. The fourth module is a CC2640 based LED module which was added last minute to add a visual indication.
The essential part of this build is the MSP432 Launchpad which is the hero of this design. It runs TI-RTOS which manages the tasks for everything including communications and sensors. I initially tested out the TI-RTOS capabilities which are documented at Safe & Sound - Safety Jacket for the Tolling Industry #3: TI RTOS and POSIX with the CC1310 Launchpad
Since the CC1310 cannot be used in my country due to frequency restrictions, I decided to use BLE for all the communication needs. The CC2650 was employed for this purpose and a detailed explanation of the BLE code and modifications is presented at Safe & Sound - The Companion IoT Jacket #10: MSP432, BLE and 3D Printing module one
I elected to go for a Fuel Tank Booster Pack for power and designed an enclousre that would expose the headers in an appropriate manner.
The sensors need to be separated and were enclosed in a badge like case that is mounted to the front of the jacket.
The connection between the two modules is accomplished via an I2C bus with just four wires traversing the inside of the jacket. My better half was responsible for the cutting and sewing and attaching everything to their rightful place. The exposed headers as seen in the image above allow for an external power pack to be connected.
The second part is the flip display which allows the wearer to get a quick glimpse of the status of the electronics. The Sharp96 display coupled with the MSP430G microcontroller on a custom PCB make for a low power component that consumes around 300uAmps at 1.8V . A working explaination of the code is presented at Safe & Sound - Safety Jacket for the Tolling Industry #7: Cloud CCS and Sample Code Issues and Safe & Sound - The Companion IoT Jacket #11: An Energy Harvesting Display
The power to the display is supplied from a SuperCapacitor managed by the BQ25570EVM enclosed in a custom box and mounted at the back of the jacket. The discharge rate was monitored and was found low enough to power the display for a few minutes even in complete darkness.
The code for the communications is a custom TLV protocol over Serial which is based on the tutorials at Safe & Sound - Safety Jacket for the Tolling Industry #5: Writing your own protocol and Safe & Sound - Safety Jacket for the Tolling Industry #6: Writing your own protocol - part 2
The construction of the Qi Power Pack is explained at Safe & Sound - The Companion IoT Jacket #12: Qi Charging with Element14, Texas Instruments and Wurth Electronics which consists of a TI and Element14 Fuel Tank Booster Pack and TI and Wurth Electronics Wireless Power Kit.
The four module is the BLE LED which is enclosed in a 3D printed badge like box.
The final project is presented at Safe & Sound - The Companion IoT Jacket #13: The Wearable Demonstration and the long demonstration video is presented below. There are so many tit-bits to this project that the video is around 30 minutes long.
I go through each module, its construction and enclosure and finally demonstrate the jacket in action.
This project took up a life of its own when all the bits and pieces started to work. My biggest accomplishment here is that all the parts being used are Texas Instruments from the MSP432 ARM controller to the MSP430 low power controller all the way from the CC2650 and CC2640 BLE controllers and BQ25570 Energy Harvesting Module and even the bq24210 Li-ion charger and bq27510 Fuel Gauge and also the bq50021a from the wireless charger. Sticking to this theme took a little more thought process and the result is an all TI project.
I am slightly disappointed that I was unable to get the GUI to work and that is partly due to the last two week of health related diversions and partly due to my inability to write mobile applications. The code I presented does work though and can be extended to work with protocols such as MQTT, AMPQ and the like.
This is an exhausting project as creating a wearable is not the same as other projects. I have learned a lot from this experience and am working to learn a bit about java for future work. I hope my tutorials and project can help someone out there. Once again our thanks to Texas Instruments and element14 for their support.