Author: sgaiter

This week, we received our board (ESP32S) and touch sensors. I started testing out the board to see how we could boot it and ended up using Arduino IDE to code. I created a simple testing structure where we could measure the relevant thresholds for each sensor and validate their functionality. I connected a touch sensor each to an ADC pin and outputted a prompt when each sensor was triggered. Some notes found were:

• When not triggered, each sensor has a different value, but all seem to be under 1000 after ADC calculations, so for validation purposes we set our thresholds to this value.
• When pressed, each sensor value reaches to on average 4000 after ADC calculations, but one of the sensors only seemed to reach 2000 with similar force.
• There seems to be a bit of variance throughout each sensor for values, so we will have to document which sensors these are and do slightly different calibrations for each sensor.

Additionally, after some confusing results, I discovered that two of the pins on the board were shorted together, pins D4 and D15, which unfortunately are both ADC pins. Since we’re not exactly sure the orientation of each sensor relative to the board, we will need to purchase a different board for the final design.

Since we have finished thresholding and setting up the sensors, we are on track for the project. Next week, we plan on receiving the other sensors and starting on IMU calculations, while also starting to map out specific placement for the sensors on the glove and how they interact with the board. I also realized during this process that we will likely need to create and order a PCB for power and signal mapping, so I will start on this next week as well.

 

 

This week, I further researched the right microcontroller to use for the project, and we’ve settled on the ESP-32S board. This is because there are more than 12 ADC inputs on the board, which is more than enough for our sensors, it has built in Wi-Fi and bluetooth, supports Arduino IDE and comes in a compact size of just over 2 inches. We’ve already ordered the board and it will come early next week. As such, I am a bit behind schedule since we were unable to receive the board this week. To make up for this, I will start interfacing with the board when it arrives, but further research on the board suggests the setup process is quite seamless when using Arduino IDE, so I don’t expect this process to take longer than a day. Additionally, I created a block diagram for the design we will use for the sensor to board interface, and started creating a schematic for the design report for next week. I researched different power sources we could use, including coin cells and lithium ion batteries. After researching the power consumption needed for each component, we have a ballpark estimate of how many mAh we need to sustain our device for our target battery life of 2-3 hours. Since we have already ordered the sensors needed as well, next week we will start interfacing the sensors with the board, and experimenting with different thresholds for the analog inputs. Intro to Embedded Systems greatly helped with the block diagram and schematic design for our project. Additionally, Electronic Devices and Analog Circuits helped me to better understand power rules and create circuit diagrams for the power structure.

This week, we gave a presentation on our project proposal. We received good feedback on our design requirements, especially the concern about the size of the board we originally picked, the STM32 Nucleo Board. We decided to look into other options for our main board, including an Arduino Uno, for its ease of use. However, we realized that for the sensors we require, we would need around 8 analog inputs (not including the IMU inputs), which is 2 more than is included on the Arduino Uno. From here, we explored other options, such as analog multiplexers to switch between each sensor input, switch matrices to utilize the 6 analog inputs on the Arduino for 9 analog signals, or a PCB with extra ADC’s. We are still in progress of choosing a main board for the project, but the feedback we received was helpful in our research. Additionally, we chose the sensors we need for the project, and are working to order them in the coming days. We are still on schedule for the project, and we hope to receive some parts by next week to test compatibility and start setting up drivers for the main board.