1. /*
2. * flowSensor.h
3. * Will White 11/7/17
4. *
5. * Library providing some basic functions for the Adafruit (plastic) flow sensor
6. * Does not use interrupts, not necessary for SG6 Auto (for which this is written)
7. * CheckFlow function is inspired by code written by Adafruit to test the sensor
8. * Current implementation is for binary readings, ie is there flow or isn't there
9. * Flow volumes are not calculated here, can be done in the future.
10. */
11.
12. #include <stdint.h>
13.
14. #define FLOW_PORT PORTD
15. #define FLOW_PIN PIND
16. #define FLOW_DDR DDRD
17.
18. uint8_t flowpin;
19. uint8_t lastState;
20. uint32_t timeCount;
21. uint32_t pulses;
22. float flowRate;
23.
24. /*
25. * initializes the flow sensor to read a particular pin in port D
26. * default pin is 3
27. */
28. void flowSensorInit(uint8_t pin);
29.
30. /*
31. * Returns a 1 if water is flowing through the sensor, a 0 if no flow is detected.
32. * reading takes about 100 ms (current implementation is relatively inefficient)
 
33. */
34. uint8_t isFlowing(void);
35.
36. /*
37. * helper function, reads the input pin and determines if a pulse has occurred. If it ha
s,
38. * the flow rate in hertz is calculated. NOT STANDALONE
39. */
40. void checkFlow(void);
41. void getReadout(uint8_t *reading);
42. float getFlowrate(void);





1. /*
2.	* FlowSensor.c
3.	* Will White 11/7/17
4.	* Implementation of flowSensor.h 5. */
6.
7.	#include "flowSensor.h"
8.	#include <avr/io.h>
9.	#define F_CPU 16000000UL
10.	#include <util/delay.h>
11.	#include <avr/interrupt.h> 12.
13.
14.
15. void flowSensorInit(uint8_t pin) { 16.
17.	flowpin = pin;
18.		FLOW_DDR &= ~(1  <<  flowpin); //set as  regular input (no  pull up  so  it doesn't sour  ce current)
19.	FLOW_PORT &= ~(1 << flowpin); // should be 0 already but just to be  safe 20.
21. } 22.
23. void checkFlow(void) { 24.
25.	uint8_t x; 26.
27.	x = (PIND &  (1<<flowpin))  >>  flowpin;  // equals  0  if pin  is  low,  1  if high 28.
29.	if (x != lastState) {
30.		if (x == 1) pulses++;
31.		lastState = x;
32.		flowRate = 1000.0/timeCount;
33.		timeCount = 0;
34.	}	
35.	else	
36.		timeCount++;
37. }		
38.		
39. uint8_t isFlowing(void) { 40.
41.	//lastState = 0;
42.	flowRate = 0;
43.	int i; 44.
 
45.	for (i = 0; i < 100; i++) {
46.	checkFlow();
47.	_delay_ms(1);
48.	}
49.
50.	if (flowRate > 0) return 1;
51.	else return 0;
52. }
53.
54. void getReadout(uint8_t *reading) {
55.
56.	uint8_t x;
57.	int i;
58.	for (i = 0; i < 500; i++) {
59.	reading[i] = (PIND & (1<<flowpin)) >> flowpin;
60.	_delay_ms(1);
61.	}
62. }
63.
64. float getFlowrate(void) {
65.
66.	uint8_t x, laststate = 0;
67.	uint32_t count = 0;
68.	int i;
69.	for (i = 0; i < 1000; i++) {
70.	x = (PIND & (1<<flowpin)) >> flowpin;
71.	if (x != laststate &&  x  == 1)	// count the rising edges
72.	count++;
73.	laststate = x;
74.	_delay_ms(1);
75.	}
76.
77.	// 450 pulses per liter
78.	return (1.0/450.0)*count*60*0.264172; // liters per second
79.
80. }