1. /*
2. * SG6auto.c
3. * Copyright (c) Will White 11/11/17
4. * Appalachian State University Honors Thesis Project
5. *
6. * Control sequence for an AVR Atmega328p microcontroller to automate a small scale
7. * snowmaking system. Interfaces with two solid state relays to control an air compresso
r
8. * and pressure washer, a solenoid valve, and a state indicator LED. Reads from a DHT22
9. * temperature and humidity sensor and an Adafruit flow sensor.
10. * The MIT License (MIT)
11. *
12. * Permission is hereby granted, free of charge, to any person obtaining a copy
13. *  of  this  software  and  associated  documentation  files  (the  "Software"),  to  deal
14. * in the Software without restriction, including without limitation the rights
15. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
16. * copies of the Software, and to permit persons to whom the Software is
17. * furnished to do so, subject to the following conditions:
18. *
19. * The above copyright notice and this permission notice shall be included in
20. * all copies or substantial portions of the Software.
21. *
22. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
28. * THE SOFTWARE.
29. */
30.
31.
32. #include <stdio.h>
33. #include <avr/io.h>
34. #include "DHT.h"
35. #include "DHT.c"
36. #include "flowSensor.h"
37. #include "flowSensor.c"
38. #include "Serial.h"
39. #include "Serial.c"
40.
41. #define ON_WETBULB 27	// degrees farenheit
42. #define TOO_HOT 100
43. #define COLD 20
44. #define FLOW_READ_PIN 3
45. #define DHT_READ_PIN 2
46. #define OUT_PORT PORTB
47. #define WATER_PIN 2
48. #define PUMP_PIN 1
49. #define AIR_PIN 0
50. #define ON 1
51. #define OFF 0
52. #define LED_PIN 3
53.
54. uint8_t systemOn;
55. uint8_t coldFlag;
56. uint8_t waterInFlag;
 
57. uint8_t pumpOn;
58. uint8_t airOn;
59. uint8_t waterOn;
60. uint32_t timeOn;
61. uint32_t timeOff;
62.
63. int temps[] = {20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
64.	38, 39, 40};
65. int hums[] = {10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,
66.	100};
67. int wbTable[21][19] = {{14,14,14,15,15,15,16,16,16,17,17,18,18,18,19,19,19,20,20},
68.	{14,15,15,16,16,16,17,17,17,18,18,18,19,19,19,20,20,21,21}
,
69.	{15,16,16,16,17,17,17,18,18,19,19,19,20,20,20,21,21,22,22}
,
70.	{16,16,17,17,18,18,18,19,19,19,20,20,21,21,21,22,22,22,23}
,
71.	{17,17,18,18,18,19,19,20,20,20,21,21,22,22,22,23,23,23,24}
,
72.	{18,18,18,19,19,20,20,20,21,21,22,22,22,23,23,24,24,24,25}
,
73.	{18,19,19,20,20,20,21,21,22,22,23,23,23,24,24,25,25,25,26}
,
74.	{19,19,20,20,21,21,22,22,23,23,23,24,24,25,25,26,26,26,27}
,
75.	{20,20,21,21,22,22,23,23,23,24,24,25,25,26,26,27,27,27,28}
,
76.	{20,21,21,22,22,23,23,24,24,25,25,26,26,27,27,28,28,28,29}
,
77.	{21,22,22,23,23,24,24,25,25,26,26,27,27,28,28,29,29,29,30}
,
78.	{22,22,23,23,24,25,25,26,26,27,27,28,28,29,29,29,30,30,31}
,
79.	{23,23,24,24,25,25,26,26,27,27,28,28,29,29,30,30,31,31,32}
,
80.	{23,24,24,25,26,26,27,27,28,28,29,29,30,30,31,31,32,32,33}
,
81.	{24,25,25,26,26,27,27,28,29,29,30,30,31,31,32,32,33,33,34}
,
82.	{25,25,26,27,27,28,28,29,29,30,31,31,32,32,33,33,34,34,35}
,
83.	{25,26,27,27,27,28,29,29,30,30,31,31,32,32,33,33,34,34,35}
,
84.	{26,27,27,28,29,29,30,31,31,32,32,33,34,34,35,35,36,36,37}
,
85.	{27,27,28,29,29,30,30,31,31,32,33,33,34,35,35,36,36,37,38}
,
86.	{27,28,29,30,30,31,32,32,33,34,35,36,36,37,37,38,38,39,39}
,
87.	{28,29,30,31,31,32,32,33,34,34,35,36,36,37,38,38,39,39,40}
88.	};
89.
90. uint8_t turnOn(void);
91. void turnOff(uint8_t error);
92. int getWB(int T, int H);
93. void turnWaterOn(void);
94.
95. int main(){
96.
 
97.	char output[30];
98.	int temperature, humidity;
99.	float wetbulbTemp, gallonsPerMinute;
100.		uint8_t successfulStartup;
101.		
102.		/* Initialization sequences */
103.		dht_init(DHT_READ_PIN);
104.		flowSensorInit(FLOW_READ_PIN);
105.		USART_init();
106.		systemOn = 0;
107.		
108.		/* Control loop */
109.		while (1) {
110.		
111.		/* check inputs */
112.		temperature = (int) readTemp(1);
113.		_delay_ms(2050);	// delay to give sensor time to send new reading
114.		humidity = (int) readHumidity();
115.		wetbulbTemp = (float) getWB(temperature, humidity);
116.		gallonsPerMinute = getFlowrate();
117.		
118.		/* check reading every minute if system is off */
119.		if (systemOn == 0)
120.		_delay_ms(60000);
121.		
122.		/* turn system off if it's not cold enough */
123.		if (systemOn == 1 && coldFlag == 0)
124.		turnOff(0);
125.		
126.		/* turn system on if it's cold enough */
127.		else if (systemOn == 0 && coldFlag == 1)
128.		successfulStartup = turnOn();
129.		
130.
g	
*/	/* turn water on at marginal temperatures to prevent system from freezin
131.		else if (wetbulbTemp <= 28 && coldFlag == 0 && systemOn == 0)
132.		turnWaterOn();
133.		
134.		/* turn system off if water shuts off for any reason */
135.		else if (systemOn == 1 && getFlowrate() < 0.3)
136.		turnOff(1);
137.		
138.		/* otherwise stay put */
139.		
140.		/* used as indicator */
141.		if (systemOn == 1)
142.		OUT_PORT |= 1 << LED_PIN;
143.		else
144.		OUT_PORT &= ~(1 << LED_PIN);
145.		
146.		_delay_ms(2000);
147.		
148.		/* debug sequences
149.		if (systemOn == 1) USART_putstring("ON ");
150.		if (systemOn == 0) USART_putstring("OFF ");
151.		if (isFlowing()) USART_putstring("FLOWING\n");
152.		if  (!isFlowing())  USART_putstring("NOT  FLOWING\n");
153.		ftoa(wetbulbTemp, output, 3);
154.		USART_putstring(output);
155.		ftoa((float) temperature, output, 3);

 
156.	USART_send(' ');
157.	USART_putstring(output);
158.	ftoa((float) humidity, output, 3);
159.	USART_send(' ');
160.	USART_putstring(output);
161.	USART_send('\n');
162.	*/
163.
164.	}
165.	return 0;
166.	}
167.
168.	/*
169.	* Turn on Sequence, returns 1 if successful, 0 if failure
170.	*/
171.	uint8_t turnOn(void) {
172.
173.	int count;
174.
175.	systemOn = 1;	// will get turned off if water doesn't flow
176.	timeOn = 0;	// measures the time the system is on
177.	USART_putstring("Turning  on\n");
178.
179.	/* turn compressor on */
180.	DDRB = 0xFF;
181.	OUT_PORT |= 1 << AIR_PIN;
182.
183.	/* turn water on (solenoid valve) */
184.	OUT_PORT |= 1 << WATER_PIN;
185.
186.	/* wait for water reading
187.	water flow should be 1.6gpm during normal operation */
188.	while (getFlowrate() < 0.3) {
189.	USART_putstring("Waiting for water\n");
190.	if (count++  >= 60) {	// wait for one minute for water to
turn on
191.	turnOff(0);
192.	ERROR(2);	// unsuccessful startup error
193.	return 0;
194.	}
195.	}
196.	//USART_putstring("Turning  Pump  On\n");
197.
198.	/* turn pump on */
199.	OUT_PORT |= 1 << PUMP_PIN;
200.
201.	return 1;
202.
203.	}
204.
205.	/*
206.	* turn off sequence
207.	*/
208.	void turnOff(uint8_t error) {
209.
210.	USART_putstring("Turning off\n");
211.	systemOn = 0;
212.
213.	// turn pump off
214.	OUT_PORT &= ~(1 << PUMP_PIN);
215.	_delay_ms(10000);
 
216.
217.	// turn air off
218.	OUT_PORT &= ~(1 << AIR_PIN);
219.	_delay_ms(10000);
220.
221.	// turn water off
222.	OUT_PORT &= ~(1 << WATER_PIN);
223.
224.	// go into error mode if water stops flowing
225.	if (error == 1)
226.	ERROR(3);
227.	}
228.
229.	/*
230.	* For use in marginal temps to prevent freezing
231.	*/
232.	void turnWaterOn(void) {
233.	PORTB |= 0x04;
234.	waterOn = 1;
235.	}
236.
237.	/*
238.	* Uses wbTable to determine the wet bulb temperature given the
239.	* temperature and humidity
240.	*/
241.	int getWB(int T, int H) {
242.
243.	int tin, hin, wb;
244.
245.	// ensure proper bounds
246.	if (T > 40) wb = TOO_HOT;
247.	else if (T < 20) wb = COLD;
248.	else {
249.	if (H < 10) H = 10;
250.	if (H > 100) H = 100; // should never happen
251.
252.	for  (tin =  0;  tin <  21; tin++)	// find temperature index in wbTable
253.	if (temps[tin] == T) break;
254.
255.	for (hin = 0; hin < 18; hin++) { // find humidity index in wbTable
256.	if (hums[hin] <= H && hums[hin+1] >= H) break;
257.
258.	}
259.	wb = wbTable[tin][hin];
260.	}
261.	if (wb <= ON_WETBULB)
262.	coldFlag = 1;
263.	else
264.	coldFlag = 0;
265.	return wb;
266.	}
267.
268.	/*
269.	* Error routines
270.	* 1 blink for DHT read error
271.	* 2 blinks for unsuccessful startup error
272.	* 3 blinks for water flow interruption error
273.	* Must reset to exit
274.	*/
275.	void ERROR(uint8_t mode) {
276.
 
277.		uint16_t length;
278.		DDRB = 0xFF;
279.		
280.		if (mode == 1) {	// DHT read error, blink once
281.		while (1) {
282.		OUT_PORT &= ~(1 << LED_PIN);
283.		_delay_ms(1000);
284.		OUT_PORT |= (1 << LED_PIN);
285.		_delay_ms(1000);
286.		}
287.		
288.		} else if (mode == 2) {	// unsuccessful startup error, blink twice
289.		while (1) {
290.		OUT_PORT |= 1 << LED_PIN;
291.		_delay_ms(333);
292.		OUT_PORT &= ~(1 << LED_PIN);
293.		_delay_ms(333);
294.		OUT_PORT |= 1 << LED_PIN;
295.		_delay_ms(333);
296.		OUT_PORT &= ~(1 << LED_PIN);
297.		_delay_ms(1000);
298.		}
299.		
300.		
301.		} else if (mode == 3) {	// water flow interruption, blink three times
302.		while (1) {
303.		OUT_PORT |= 1 << LED_PIN;
304.		_delay_ms(200);
305.		OUT_PORT &= ~(1 << LED_PIN);
306.		_delay_ms(200);
307.		OUT_PORT |= 1 << LED_PIN;
308.		_delay_ms(200);
309.		OUT_PORT &= ~(1 << LED_PIN);
310.		_delay_ms(200);
311.		OUT_PORT |= 1 << LED_PIN;
312.		_delay_ms(200);
313.		OUT_PORT &= ~(1 << LED_PIN);
314.		_delay_ms(1000);
315.		}
316.		
317.		}
318.		
319.	}	
320.		
321.