I am 8, and I always try creating new things. I like to combine art and technology. I have created a running water display showing a circle with a diameter and the symbol pi inside it. I decided to make this because I saw water swirling inside a food grinder on the kitchen countertop. At first, my idea was to have a clear container with the symbol pi made of clear tubing inside it and pump colored water through it. I thought the colored water flowing in a clear tube will look awesome just like water swirling inside the food grinder. I later thought that since it is Pi, and I wanted to show what it really meant, I wanted to show the circumference, diameter and the symbol Pi all in a circle and make it out of clear tubing so that I can pump colored water through it. I borrowed 2 motor pumps and gummy tubing. I also went out with my parents and bought 1/2 inch diameter elbows, connectors and clear tubing. I first draw the circle and the diameter and pie symbol on a piece of paper and pasted it on top of a cardboard box. I then used clear tubing and marked the points where the tube should be tied up with zip ties to the box. My dad punched holes to put elbow connectors for water feed and drain for motor pumps and connected gummy tubing on the underside of the box. Very simple -water pumps push water in through one tube, it goes around, and it comes out through another tube into the same container where the pump is. I used two different colors and so used 2 pumps. You can connect the tubes in whatever shapes you want. Later, instead of plugging the motors into a wall outlet, I used relay modules, a bit of python code from a youtube tutorial on how to use Gpio, and my Raspberry Pi to turn the motors on and off. The idea was mine, because long ago I saw in a youtube video that we can control input /output safely using relay modules and raspberry pi. My dad helped me with the wiring for the motors, and my mom helped with relay-motor connections, and debug the python code to make it work with the relay. I wired the relay input 1 and 3 to the raspberry pi board pins 11 and 18, and also connected 5v and ground pins to the relay modules.
Our relay module was defective was turning on even during the setup() function call in the code. So we had to increase the sleep time after the relay was turned off in code to close the circuit. The correct code for working with a non-defective relay will be included in the comments in code. -edited by parent.
Code to complete circuit using Raspberry Pi GPIO and relay modules
Python
to run the code, open a terminal on raspberry pi, change to the directory where you saved the code, and run it as superuser. The command to run is sudo python <filename>.py
#!/usr/bin/env pythonimportRPi.GPIOasGPIOfromtimeimportsleepCircle_relay=11Diameter_relay=18'Using 4 times Pi as sleep number in code'FourTimesPi=3.14*4defsetup():GPIO.setmode(GPIO.BOARD)GPIO.setup(Circle_relay,GPIO.OUT,initial=GPIO.LOW)GPIO.setup(Diameter_relay,GPIO.OUT,initial=GPIO.LOW)defmain():print'... Circle relay channel on'GPIO.output(Circle_relay,GPIO.HIGH)GPIO.output(Diameter_relay,GPIO.HIGH)sleep(2)print'... relay channel off'GPIO.output(Circle_relay,GPIO.LOW)GPIO.output(Diameter_relay,GPIO.HIGH)sleep(FourTimesPi)defdestroy():GPIO.output(Circle_relay,GPIO.LOW)GPIO.output(Diameter_relay,GPIO.LOW)GPIO.cleanup()if__name__=='__main__':setup()try:main()GPIO.cleanup()exceptKeyboardInterrupt:destroy()
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