Introduction: Auto Ph

WARNING: github link doesn't exist anymore

Hello, I am a MCT studenst from Howest Belgium.

Have you ever wanted to automate the Ph in your pool/jacuzzi/hottub? Then this might be something for you.

I've made a device that will automatically adjust the Ph level.

Step 1: Supplies

You need the following items:

  • Raspberry pi4
  • Arduino Uno
  • LCD display 16*2
  • 16gb SD card
  • 5v usb-c power supply for raspberry pi
  • Ph sensor
  • 12v peristaltic pump (2x)
  • DS18B20
  • 20kg weight sensor (2x)
  • HX711 module (2x)
  • L298N motor driver module
  • 4.7k ohm resistor
  • 10k ohm potentiometer
  • breadboard
  • jumper wires
  • filament for your 3d printer
  • paint (optional)

Tools I used:

  • 3d printer
  • saw
  • brushes
  • drill

Step 2: Housing

I made a housing out of wood. You can adapt the design to your Ph containers

Step 3: Beginning

For the case I've got help some help from my grandpa. We started by making a frame. I made my housing 70cm tall, 30cm wide and 15cm deep. The housing has to be at least 15cm deep otherwise you won't be able to fit all the electronics easily. For connecting all the pieces of the frame we used wood glue and nail. For extra stability while the glue was drying we added a couple of screws.

The back of the case is glued and nailed on the frame.

On the right side we made 1 hole to pass through the 2 power cables. The top get 4 holes. 1 for the Ph sensor, 1 for the temperature sensor and 2 for the Ph tubes

Step 4: Adding the Weight Sensors

While the front is still open we added a piece of wood to the bottom for the weight sensors. The wheight sensors are screwed in place. For the top we first added a small piece of wood as a spacer and the a larger peice where we can fit the bottles on.

Step 5: The Front

the front consists of 3 pieces. A smaller piece on the bottom to cover the weight sensors. A door in the middle and at the top another piece of wood to cover the rest of the ellectronics. The door gets hinges, the top and bottom get screwed in place. The top piece received some extra attention. We needed to make a hole for the LCD.

Step 6: Painting

Because mdf wood isn't that appealing I've painted the housing white

Step 7: 3d Print

I made a mount for the peristaltic pumps. You could also make this out of wood.

To connect the tube to the pumps I used from Boerni.

Step 8: Adding the Circuit to the Case

To mount the RPI, arduino, lcd, motor controller and pumps I used screws. For everything else I used hot glue. If anything would break it can easily be replaced.

Step 9: Wiring

For my project I used the arduino to to send the Ph and weight values to my RPI through serial communication over USB. The LCD, temperature and motor controller are directly connected to the RPI.

Step 10: Database

My database isn't big: I just needed to save the sensor data. This data i could later use for a history garph.

All the sensor names are stored in device, the measurements are stored in measurements (what a suprise :p). These 2 tables are connected with a anonther table. By doing it this way I could easily expand the database later.

Step 11: Code