Tracer | A Wearable for Things!

As the "Tracer" project nears completion, we've reached two significant milestones: the final design testing and the preparation for a bulk order. Our rigorous testing phase ensured Tracer's reliability and efficiency. Highlights include:

• Real-time Object Tracking: Leveraging the LSM6DSL, we achieved precise tracking of various objects.
• Mounting Versatility: Our high-quality velcro straps showcased adaptability, proving effective on diverse objects from bicycles to tennis racquets.
• Battery Efficiency: Tracer demonstrated a robust battery life, with 2.5 hours of continuous BLE streaming at 10Hz.
• Connectivity Range: In open spaces, notably a tennis court, we achieved an impressive 15m BLE range.
• Use Cases: Integration with the Madgwick Filter allowed for effective sensor fusion, estimating parameters like heading, roll, and pitch. This data was seamlessly transmitted to devices such as smartphones and PCs.

With the successful testing phase behind us, we're thrilled to announce the preparation for a bulk order of Tracer. This step underscores our confidence in Tracer's market potential. A special acknowledgment to JLCPCB, whose expertise in rapid prototyping without quality compromise has been invaluable. Their support has been instrumental, and for those venturing into board design, JLCPCB comes highly recommended for their quality, affordability, and efficiency.

As we transition to this next phase, heartfelt thanks to everyone who has supported and believed in this journey. Your feedback and encouragement have been pivotal. Stay tuned for more exciting updates on Tracer!

ANNOUNCEMENT 

Thank you all for the support I have received over the past year. 

I really appreciate the comments and feedback through this forum and I fully intend to update my content here frequently with useful content as soon as they become available. However due to the format of this platform, it is quite difficult to present small yet important updates, therefore I am creating an Instagram page where I will post my content more regularly and also demonstrate more of the "behind-the-scenes" work that goes into creating my projects. 

You can access my Instagram page here, elektroThing (@elektrothing) • Instagram photos and videos.  For those of you who do not want to use Instagram, I am also launching my website, elektrothing.com, which will serve as the landing page for all things elektroThing. :) 

PROJECT UPDATE

It works as a tennis tracker and a data streamer! 

However, battery life needs to be better and I have a few plans for that; 

1. Writing better firmware - devising a scheme such that the BLE modem doesn't have to be "always-on" whilst preserving all the features.
2. Swapping out the MCU maybe? As WiFI is not really needed, I am planning to use a Nordic MCU instead of the ESP32 which should give better sleep currents. 
3. Design low voltage protection to avoid deep discharge to protect the battery further. At the moment it is only implemented in software.

Do reach out if there is something on this list that you would like to help with. I am more than happy to send over a board and in return get some work off my shoulders.

Hi all,
I have just received my 30 units and they are ready to be shipped out to you! :)
You can find them on my Tindie store or through this link. Tracer from elektroThing on Tindie

Hi all, here's a small but significant update! :) 

Sorry for the radio silence this past month but I am pleased to announce that I am finally happy with the state of the design and have added a small power switch to improve the usability of Tracer. And with that, I have placed an order for 30 units to be made up, they should be in stock before the end of the month and I will aim to ship them out ASAP from my Tindie store. 

I am really looking forward to seeing how you will use them and hearing feedback on how the design could be improved further! :) 

YJ

I have been inspired over the last few weeks by Fabio's project with Edge Impulse and how the Tracer platform can be used to leverage the ESP32's processing power to run neural network classifiers of activities and gestures. In this example, I will go through the steps needed to train your own neural network and show it performing live classification with data streamed directly from the board. 

I wrote an Arduino sketch that would spit out the 3-axis accelerometer and 3-axis gyrometer at a frequency of 100Hz. The experiment I had in mind was basically to use Tracer as a classifier that could tell if it was moving horizontally, vertically, "caterpillar" (move in a jagged way horizontally), and waving. A dataset of 10s was collected for each of the movements.

Once I had an idea of what I wanted to build, I followed the steps shown in the video tutorial from Edge Impulse in getting a model trained up as well as a k-means-based anomaly detector.

The initial model that was trained showed inaccuracies when it came to classifying a wave and that is due to several reasons but I think it was primarily due to not having enough data. The table below shows the confusion matrix for the first training cycle with the original dataset.

Following that, I wanted to see if collecting more data would improve so I spent another 10 seconds collecting data for wave, and it improved slightly. I think more data in each category should improve the neural network's specificity and sensitivity. The accuracy improved across the board while the error rates also dropped.

Here is a short video example of how the live classification tool is being used on the data that is streaming directly from Tracer over USB (UART). The next step for me is to deploy a real-time classifier for tennis shots that will run on the ESP32 and stream the results over BLE.

And again as before, really happy to hear any feedback, ideas or suggestions!

Hi all,

I am grateful for the warm reception, the development units I had sold out in less than 12 hours and I plan to place an order towards the end of the month. Please register your interest if you are keen on getting hold of this;
It will ship with the board itself and a high-quality velcro strap that can quickly get you started gaining insights. Due to restrictions on Lithium-Ion batteries, you will have to source the LIR2450 on your own but that is quite commonly available and can be found on Amazon and RS for example. 

Eager to get these boards out there to see what interesting applications can arise through the open-source community! Also, any feedback is greatly appreciated. 

Best, 

YJ

Hi all,

Just a small update with hopefully bigger ones imminent. I have received my new Tracer boards that are now smaller and have a better-suited LDO with a very low forward drop to increase the usable range of battery voltages from the coin cell battery.

I am currently planning the following activities; 

1. Testing it out for tennis stroke counting - Done
2. Tracking bicycle cadence - Done
3. Using it to synchronize blade strokes at my local rowing club 
4. Power measurements and optimization - Done
5. Syncing with camera footage to add data points and improve the usability 
6. Create a Tracer "hub" to synchronize several modules. Still thinking about the best way to do this as BLE might be a little limiting. Feel free to suggest :) 
7. Setting up a Crowdsupply campaign to get the hardware out to you! - On Tindie for now

Thank you all for liking and following this project it means a lot to me and it helps me keep going! 
Best,

YJ