Through my own ECE engr portal, I purchased those parts on digikeys and mouser. This order is approved later.
# 2022/2/14
In today's work, we finished our design documents and RV tables.
The supply voltage needs to be within the range of 3.3V ±5% and power 1.5mA of current during write cycles
1A. Using an oscilloscope, ensure the power supplied is above 3.3V ±5%.
1B. Using a multimeter, verify the power draw during write cycles is below 1.5mA
The system would be able to detect and eliminate noises in data.
2A. Simulate a noise signal and add it to one of the lines. Then check on an oscilloscope to see if the signal is filtered out.
256KB of data sent from MCU via Bluetooth is received by software.
1A. Check to see if Bluetooth data is being transmitted at a rate of 2.4 GHz.
1B. Analyze data received by software via Bluetooth for any missing/corrupt sensor readings within the packetized 6x10 array.
Successfully pair with an Android device.
2A. See if IntelliSole is recognized as a Bluetooth device on the software host.
Software must retrieve correct sensor values and not lose any timestamp of data in the process.
1A. Read through ADC sensor data stored in SD card (or Bluetooth) by .
1B. Check to see any corruption of values within the 6x10 array.
Given sensor data, the front end must display the recorded data in the form of a heatmap.
2A. Use the android studio debugger to step through the visualization of the pressure heatmap.
2B. Verify the playback on the user interface by replaying the same data again.
# 2022/3/15
In today's meeting, we modified our subsystem expectations. Data storage subsystem is decided optional for that testing is only available after PCB manufacture.
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@@ -83,6 +104,11 @@ In today's meeting, we modified our subsystem expectations. Data storage subsyst
Today, we participated in the Pressure Data Acquisition subsystem verification by helping establish the pressure sensor’s linear response zone. Now the Pressure Data Acquisition subsystem can read valid pressure values and the circuit can convert resistance value to voltage values. One of the key problems is to establish a linear response zone for the pressure sensor so that we can decide the validity of pressure data later in the signal processing stage and also build a force/pressure to voltage relation based on this. Due to the limits in the lab, we decided to approach this problem by filling up a water cup with water gradually and building a plot with the voltage values read and amount of water in the cup. As seen in the figure, the cup itself is weighing 4.5 gram, and we fill the cup each time with ¼ cup of water which is roughly 60 milliliter until the cup is full which contains 250 ml of water.
According to the linear regression model, the model has mean square error of 13.88 and regression p_value of 0.00083 which is considered statistically significant for the model to be considered linear.
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I also participated in the Bluetooth Data Transfer subsystem and User Interface subsystem to establish bluetooth connection. Bluetooth Data Transfer subsystem can also be enabled and connect to a third party application. My next step will be to continue to work on the bluetooth module and verify data flow acquired by the sensor can be transmitted to our frontend application. I will also need to build a frontend script that handles the input and convert data into a plot. The last thing needed to do is to build a Data Storage subsystem that can store the data when bluetooth function is disabled.
