What did you personally accomplish this week? Give files or photos that demonstrate your progress. Prove to the reader that you put sufficient effort into the project over the course of the week (12+ hours).
- Ordered and tested Hall sensors. After a lot of research, I found these ultra-high sensitivity linear hall sensors:
- https://content.instructables.com/ORIG/FHV/BQO4/JVR5YV9R/FHVBQO4JVR5YV9R.pdf
- I also determined their range and region of optimal operation.
- I did a comparative analysis between these sensors and the ones we had tested before (magnetometers, inductive coils). Concluded that these are best suited to our needs. The linear output of these sensors will also allow us to view the magnitude of change in the voltage across different sensors closest to the device and estimate the location of the device better than we would with a binary output.
- This is the code I used on the Arduino to interface with the sensor: (OS → GitHub) https://drive.google.com/drive/folders/1XTErRDNUgChzzYopmD6_mG5LmT11oCgk?usp=sharing
- I was using the Serial Monitor to view changes in Hall Voltage as the devices were brought closer. This was just for preliminary testing.
- Spent 5–6 hours in the lab with Callum trying to figure out the ideal placement for the sensors to achieve the best coverage with minimum components. We came up with the result that our sensors can cover a 16 cm^2 area on the surface. So, our sensors will have to be ~4 cm apart. We will be making the sensing array on our own, using through-hole components and flat wiring. The acrylic surface will have indents created for the parts to sit in, this will allow for the highest proximity between the sensors and device.
- After this, I also spent some time deliberating different sensing array setups to minimize cabling and maximize the ease of reading the output from various sensors. I decided on cascaded analog decoder chips that would allow us to use select lines to sweep different sensor locations and read sequentially, minimizing the number of Analog-In Arduino pins needed.
- Callum has also created a CAD sensor schematic based on our discussion for us to use.
Is your progress on schedule or behind? If you are behind, what actions will be taken to catch up to the project schedule?
- I think my progress as well as that of our team is on schedule!
What deliverables do you hope to complete in the next week?
- Me and Callum are going to solder together a small-prototype sensing array to test with our phones and devices. Once we have made sure that they work and have adjusted the distancing and spacing, we will place the order for the components required for the sensing array. This should be done by next Thursday.
- We have also purchased a couple of charging coils. They should be in by next week. We want to test their charging range and how they perform with different layers in between the charger and the device. This will allow us to decide on the surface material thickness and charging coil model.