-
Notifications
You must be signed in to change notification settings - Fork 769
/
Trinket_Ultrasonic_Rangefinder.ino
120 lines (104 loc) · 3.79 KB
/
Trinket_Ultrasonic_Rangefinder.ino
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
// SPDX-FileCopyrightText: 2018 Mikey Sklar for Adafruit Industries
// SPDX-FileCopyrightText: 2018 Anne Barela for Adafruit Industries
//
// SPDX-License-Identifier: MIT
/*
Demonstration sketch for Adafruit LCD backpack
using MCP23008 I2C expander and Maxbotic LV-EZ1 Ultrasonic Sensor
(other pin compatible Maxbotix sensors should also work)
Tested with the 5 volt Trinket mini microcontroller at 8 MHz
The ultrasonic sensor and pin use should be Gemma and Trinket 3V compatible
This sketch reads the LV-EZ1 by pulse count and prints the distance to the LCD
The circuit:
* 5V to Arduino 5V pin, I2C Backpack 5V and EZ1 +5
* GND to Arduino GND pin, I2C Backpack GND and EZ1 GND
* Display I2C Backpack CLK to Trinket GPIO #2
* Display I2C backpack DAT to Trinket GPIO #0
* LV-EZ1 Ultrasonic Sensor PW pin to Trinket GPIO #1
Portions of code provided free use on http://playground.arduino.cc/Main/MaxSonar
by Bruce Allen and Bill Gentles
Version 2.0 Adds Arduino IDE 1.6.7 and greater Wire support
Anne Barela for Adafruit Industries
*/
// include the library code
#include <Adafruit_LiquidCrystal.h> // Tiny LiquidCrystal library using TinyWireM
#define EZ1pin 1 // Trinket GPIO #1
// Connect display via i2c, default address #0 (A0-A2 not jumpered)
Adafruit_LiquidCrystal lcd(0);
// These values are for calculating a mathematical median for a number of samples as
// suggested by Maxbotix instead of a mathematical average
int8_t arraysize = 9; // quantity of values to find the median (sample size). Needs to be an odd number
//declare an array to store the samples. not necessary to zero the array values here, it just makes the code clearer
uint16_t rangevalue[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0};
uint16_t modE; // calculated median distance
void setup() {
pinMode(EZ1pin, INPUT); // Sey ultrasonic sensor pin as input
lcd.begin(16, 2); // set up the LCD number of rows and columns:
lcd.setBacklight(HIGH); // Set backlight on (HIGH on, LOW off)
}
void loop() {
int16_t pulse; // number of pulses from sensor
int i=0;
while( i < arraysize )
{
pulse = pulseIn(EZ1pin, HIGH); // read in time for pin to transition
rangevalue[i]=pulse/58; // pulses to centimeters (use 147 for inches)
if( rangevalue[i] < 645 && rangevalue[i] >= 15 ) i++; // ensure no values out of range
delay(10); // wait between samples
}
isort(rangevalue,arraysize); // sort samples
modE = mode(rangevalue,arraysize); // get median
lcd.setCursor(0, 0); // write data to LCD display via I2C backpack
lcd.print("Range: "); // write to LCD
lcd.setCursor(7,0);
lcd.print(" ");
lcd.setCursor(7,0);
lcd.print(modE);
lcd.setCursor(11,0);
lcd.print("cm");
delay(500); // Read every half second
}
// Sorting function (Author: Bill Gentles, Nov. 12, 2010)
void isort(uint16_t *a, int8_t n){
for (int i = 1; i < n; ++i) {
uint16_t j = a[i];
int k;
for (k = i - 1; (k >= 0) && (j < a[k]); k--) {
a[k + 1] = a[k];
}
a[k + 1] = j;
}
}
// Mode function, returning the mode or median.
uint16_t mode(uint16_t *x,int n){
int i = 0;
int count = 0;
int maxCount = 0;
uint16_t mode = 0;
int bimodal;
int prevCount = 0;
while(i<(n-1)){
prevCount=count;
count=0;
while( x[i]==x[i+1] ) {
count++;
i++;
}
if( count > prevCount && count > maxCount) {
mode=x[i];
maxCount=count;
bimodal=0;
}
if( count == 0 ) {
i++;
}
if( count == maxCount ) { //If the dataset has 2 or more modes.
bimodal=1;
}
if( mode==0 || bimodal==1 ) { // Return the median if there is no mode.
mode=x[(n/2)];
}
return mode;
}
return 0;
}