ECE 362 Group Project

Make an Etch a Sketch (with an stm32)!

A brief description of our project and what it will be able to do:

An etch-a-sketch with two knobs (potentiometers) that will record motion to an LCD screen allowing the drawing of images. Additionally using an accelerometer the user will be able to shake the screen and reset their drawing. A user can also switch between screens by tilting the etch-a-sketch, and screens are saved using an SD card and loaded on power up.

• An ability to display a traced line on the TFT display using SPI protocol
• An ability to receive and translate analog voltages into positional information using the internal ADC peripheral
• An ability to save and retrieve screens/drawings to an SD card
• An ability to use an external I2C accelerometer to clear the screen or change between saved drawings

Main features of our project:

Our etch-a-sketch will have 3 external components: the TFT LCD display & SD card reader, the two potentiometers, and an I2C Accelerometer, and 2 potentiometers for X and Y control.

The TFT LCD display/SD card reader and potentiometers are already in our lab kits, although we may procure better potentiometers from the ECE shop which has a drawer full. We also plan on using an I2C accelerometer to shake the board and clear the screen. For this, we would like to use https://www.adafruit.com/product/2019?gad_source=1&gclid=Cj0KCQjwu-63BhC9ARIsAMMTLXQVQhPq4wVcWrk7dFT_t-0NDRVO2zZFT1a4A0YmWToC_e04hHX0ia0aAqd-EALw_wcB which we will purchase when our project has been approved (or find an alternative I2C accelerometer in the ECE shop if they have one).

Eternal interface formats our project will use:

Our system will take in input from 2 different external sources: two potentiometers, and an accelerometer. These parts should be readily available in the ECE shop or cheap to purchase. We will choose whatever is optimal for the constraints of this project without needing to purchase extra parts. These external parts will utilize the following formats:

• SPI for display & SD card reader
• Analog for input of knobs
• I2C for accelerometer

Internal peripheral subsystems our project will use:

The 4 internal peripheral subsystems that our project is gonna use are:

• At least 1 timer for updating the display and 1 timer for triggering DMA request
• An ADC for the x-axis and y-axis knobs
• a DMA for the ADCs
• An SPI for the display system for the etch-a-sketch.

Planned timeline for completing the various steps of our project:

Schematic complete 10/21 Pseudocode complete 10/21 Breadboard Done 10/26 Initial Code Complete 11/2 Final integration complete 11/9 Project works by 11/16

Related published projects, products, or articles that you found that are similar to our project:

There was one previous ECE 362 mini-project that implemented an etch-a-sketch, the video showing the final product is below: https://www.youtube.com/watch?app=desktop&v=kgjA8iDKNtA While this is a good example of a successful implementation of this project, ours will have some differences. They are best described through the following points:

• Different display: LCD rather than an LED matrix (greater resolution)
• Different physical implementation