Current Risks:
  • More problems arise upon integration of all project modules
  • Catastrophic failure of a component or set of components before demo
  • Damage to PCBs or Arduino’s during capacitor soldering or voltage testing
Schedule Changes:

No schedule changes this week

Design Modifications:

As Anirud explained in his post, we are planning to possibly change resistor and capacitor values on our boards. We currently have an amplification of around 5/3 on the op-amps and coupling capacitors set at 100 micro farads. We are aiming to increase these values due to the increased voltage we intend to emplace on the matrix system.

List all unit tests and overall system test carried out for experimentation of the system.

Matrix:

  • Testing individual sensor performance (V/mm for device placement)
  • Testing single PCB performance
  • Testing overall matrix performance
  • Testing polling rates for the matrix (col/ms)
  • Testing voltage levels on matrix power rails
  • Matrix power consumed

Ammeter/Charger:

  • Amperage through charger with respect to device distance
  • Total minimum and maximum amperage values
  • Testing how amperage changers as device charge increases
  • Maximum charging distance and efficiency

Gantry:

  • Speed limit testing: How fast we can safely operate the gantry
  • Torque limits: In hand with speed, how much power we can safely operate with
  • Time testing: The longest and average time for the gantry to move to a position

System:

  • Total Latency: The total time taken between device placement and charging
  • Total Accuracy: How close we can predict device location using all modules
List any findings and design changes made from your analysis of test results and other data obtained from the experimentation.
  • We found charging distance to have a maximum of around 2cm, giving us more leniency in PCB and top panel sizes. We used this information to save budget by not purchasing thin/flexible PCBs
  • Whilst testing the power consumed by the matrix, we found that we were limited by the Arduino’s available amperage. This led to our decision to use an external source to power the matrix. Through this testing, we also experimented with using higher voltages through the system which gave us a higher sensing accuracy – we plan for our final implementation of the matrix to run on 5.7V.
  • Through testing matrix and ammeter accuracy, we found that the former was less accurate than expected, whilst the latter was far more than expected. Using this information, we changed our design for software to use the matrix to find general location, and the ammeter to precisely find the location given the matrix prediction.
  • We found that our total latency was bottlenecked by the gantry system and was minimally impacted by the low polling times we were able to achieve from the matrix. From this information, we decided to minimize polling times as much as possible for the final build.