Nadine H. Tuhaimer

Fab Academy 2018 | How to make almost anything






Input & Output Devices


The PCB board I made is an Arduino IDE compatible board since I used the atmega328P as the brains of my system.

At first, I wrote small portions of the code to test each part on its own.

At first I used the Servo Sweep Example to see what shapes will the water flowing create while it's attached to the servo. I have only added a minor adjustment which is reading the input of the potentiometer connected on pin A0 to decide what delay is the best for me.

                
float x,y; #include <Servo.h> Servo myservo; // create servo object to control a servo int pos = 0; // variable to store the servo position void setup() { Serial.begin(9600); myservo.attach(9); // attaches the servo on pin 9 to the servo object } void loop() { x = analogRead(A0); y = map(x,0.0,1023.0,0.5,10); Serial.println(y); for (pos = 160; pos <= 180; pos += 1) { // goes from 160 degrees to 180 degrees // in steps of 1 degree myservo.write(pos); // tell servo to go to position in variable 'pos' delay(y); // waits the amount of delay read from the potentiometer } for (pos = 180; pos >= 160; pos -= 1) { // goes from 180 degrees to 160 degrees myservo.write(pos); // tell servo to go to position in variable 'pos' delay(y); // waits the amount of delay read from the potentiometer } }

The servo I used is a Micro Servo motor as seen in the below image.


The above video shows my tries and how the water behaves when I change the delay based on the potentiometer.

Next, I tested the LED strip, I downloaded the FASTLED Library from github and tested the strobing using the below code.

        
#include <FastLED.h> // How many leds in your strip? #define NUM_LEDS 30 // For led chips like Neopixels, which have a data line, ground, and power, you just // need to define DATA_PIN. For led chipsets that are SPI based (four wires - data, clock, // ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN #define DATA_PIN 7 // Define the array of leds CRGB leds[30]; void setup() { FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS); } void loop() { // Turn the LED on, then pause memset(leds,(255,255,255),sizeof(leds)); FastLED.show(); delay(500); // Now turn the LED off, then pause memset(leds,(0,0,0),sizeof(leds)); FastLED.show(); delay(500); }

I got the LED Strip from Amazon.


Next, I had to put them all together in one code. I had a problem with the timing. I need the pump to keep operating all the time with certain pulses. And the same goes for the LED Strip and the Servo Motor.

Luckily I found a timer library and use it. The code is seen below.

        
//Flash two LEDs at different rates using Simon Monk's Timer library //http://www.doctormonk.com/2012/01/arduino-timer-library.html // //Jack Christensen 30Sep2013 // //Beerware license: Free for any and all purposes, but if you find it //useful AND we actually meet someday, you can buy me a beer! #include <Servo.h> #include <FastLED.h> #include "Timer.h" //http://github.com/JChristensen/Timer int pos=0; int pump = 5; // pump is connected to pin 5 int pos1=170; int pos2=180; #define potentiometer A0 // to get the reading of the potentiometer and write it to the delay of the servo. unsigned long PERIOD1 = 2; Timer t; Servo myservo; #define LED_PIN 7 //Strip Data pin is connected to pin 10 of the arduino #define NUM_LEDS 30 // initially there were 30 LEDs in the strip, I cut the last 2 so there are only 28 now CRGB leds[NUM_LEDS]; //initial values for the LED int x = 100; int y = 50; int z = 20; unsigned long previousMillis = 0; // will store last time Servo was updated unsigned long previousMillisLED = 0; // will store the last time the LED was lit // constants won't change : long interval; // for the servo delay long intervalLED = 20; // for the servo delay of the LED Strip void setup(void) { Serial.begin(9600); // for BT communication FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, NUM_LEDS); myservo.attach(9); //define the LED Strip used pinMode(pump, OUTPUT); t.every(15,servo); // call the servo function every 15 milliesecond t.every(25, LED); // call the LED function every 25 milliesecond t.oscillate(pump, PERIOD1, HIGH); } void loop(void) { t.update(); //Update the timer if (Serial.available()){ // check if data is received { char input=Serial.read(); switch (input){ case '1': // stop the servo pos1=0; pos2=0; break; case '2': // let the servo sweep pos1=170; pos2=180; break; case'3': // turn off strip x=0; y=0; z=0; break; case '4': //light the strip back x = 80; y = 0; z = 125; break; case '5': // Make LED strobe slower intervalLED=30; break; case '6': intervalLED=5; // Make LED strobe faster break; case '7': intervalLED=20; // Make LED strobe medium break; } } } } void servo(){ // Servo Function interval= map (analogRead(potentiometer),0,1023,0,10); // change the delay of the servo depending on the potentiometer reading for (pos = pos1; pos <=pos2; pos += 1) { // goes from 0 degrees to 180 degrees // in steps of 1 degree myservo.write(pos); }// tell servo to go to position in variable 'pos' unsigned long currentMillis = millis(); if (currentMillis - previousMillis >= interval) { // save the last time you blinked the LED previousMillis = currentMillis; // waits 15ms for the servo to reach the position for (pos = pos2; pos>= pos1; pos -= 1) { // goes from 180 degrees to 0 degrees myservo.write(pos); // tell servo to go to position in variable 'pos' delay(5); // waits 15ms for the servo to reach the position } } } void LED(){ memset(leds,(x,y,z),sizeof(leds)); //use this instead of for loop FastLED.show(); unsigned long currentMillisLED = millis(); if (currentMillisLED - previousMillisLED >= intervalLED) { previousMillisLED = currentMillisLED; // save the last time you blinked the LED memset(leds,(0,0,0),sizeof(leds)); FastLED.show(); } }

The pump I used is a washer pump that runs on 5V-12V. I only needed 5V for my project.


I used a 10K potentiometer to control the delay of the Servo.


It worked out perfectly. Check out the bluetooth communication in the Networking section of the final project.



You can download the code HERE.

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