Matthew Sato
[email protected]
Autumn 2023
This repository contains three folders: electrical, software, and docs which contain all the project deliverables for this project. The project summary with my perspectives on this project is located at the bottom of this page.
The smart pot is designed as a completely autonomous plant pot that gives you the ability to be a plant parent without the trouble of remembering to water it on a regular basis. It gives water to the plant when it actually is thirsty. Now you can travel without being worried about watering your plant!
- Senses the ambient air temperature and soil moisture of the plant
- Automatically pumps water into pot when soil moisture drops too low
- Sensor to indicate when the water reservoir is low
- Display to show the temperature
- Ability to change temperature units, activate pump manually, and change the threshold at which the pump is activated
- Serial desktop interface and web-based HTML interface
- The features are fully integrated across the board, serial interface, and webpage. Any update in setting in one of these interfaces results in the corresponding update to the other interfaces.
- The Smart Pot is built on a PCB and is under the control of a PIC32 microcontroller
- Temperature sensing is performed via a thermistor
- Soil moisture sensing is performed with two probes manufuctured on a PCB
- The water tank sensor is a limit switch which is activated by a plunger when the water is too low
- The WiFi capability is added with an ESP32 and communicates with the PIC32 via SPI
- Powered with a 5 V DC barrel jack
- A 7 segment display implemented with shift registers and SPI
- 2x UART to USB bridges to allow serial communication with a desktop machine
To learn more about the product, visit the following folders:
docs: contains the product brief, product requirements, product design document, bill of materials, bringup plan, and unit tests documentelectrical: contains the detailed KiCad schematic and PCB layoutsoftware: contains the software for the Smart Pot
The fully functional board appears as follows:
A. The power supply barrel jack. Insert 5V DC only.
B. The display for the product. Can show temperature in F/C, or the soil moisture percentage
C. The function button. Short pressing once will switch the watering frequency to between the low threshold and the high threshold. A long press will activate the pump. A double press activates selection mode. In selection mode, you can click the button to select Fahrenheit units, Celsius Units, or Soil Moisture to display. After 5 seconds of inactivity in selection mode, the display will show the desired quantity.
D. The serial output. Connect this USB-Micro port to your computer and see the current data using a baud rate of 115200. I recommend TeraTerm, and the proper driver for a CP2102 USB-UART driver must be installed on your machine. The output looks like the following:
E. These two LEDs indicate if the low soil moisture threshold or high soil moisture threshold are selected.
F. This blue LED indicates when your water tank is low:
G. The port for the pump
H. The ports for the soil moisture probes. The probes should be placed in the pot approximately one inch apart:
I. The ports for the water tank level sensor. The sensor can be mounted as follows:
The unit should be turned on for approximately 5 minutes before a reliable temperature can be maintained.
All data can also be viewed on a web browser:
- In retrospect, why you found this project compelling and was the scope of the project comfortable.
- I liked that this project allowed us to design a product from start to finish. Going through the design process and how this influences the eventual circuit and PCB design was very informative.
- I thought the scope of the project was fine, just a little more time at the end would have been nice.
- What were the areas that you learned the most.
- I learned how to design a circuit from start to finish, including choice of parts. Selecting a part from DigiKey can be daunting, but this project helped me learn how to do this.
- I also learned a lot from the board bringup --- how to test if things are working, and how to fix poorly soldered joints with a heat gun.
- What are you proud of about the project.
- After taking ME218, I felt confident about my ability to program a microcontroller to do useful tasks. I am proud that I was able to transfer the skills to the PCB using a slightly different microcontroller and now feel like my capabilities are much larger than before.
- What might you do differently.
- I would have not used any QFN packages in my design --- these are hard to solder!
- I would have spent more time doing floor planning in the PCB design before routing the copper.
- Now that you know how to build a PCB based system, what might you want to attempt next?
- I plan to use my PCB knowledge to design PCBs for my research project(s), including the design of a low-level controller for a mobile robot.