使用Arduino开发板、LCD和键盘可以轻松实现一个简单的基于Arduino的计算器，使用键盘和LCD来解决数学计算。使用此项目可以轻松完成简单的数学计算，例如加法、减法、乘法和除法。

1602 LCD能够解决16位之内的数学计算，而无需延迟和快速处理。Arduino程序也很简单，几乎就像简单的C程序，仅基于加、减、乘和除的简单公式。那么，让我们实现这个简单的小项目。

电路图和要求

电路图非常简单，既可以直接在Arduino开发板上组装电路，也可以通过制作pcb组装电路。电路组件列表如下。

●    Arduino Uno开发板

●    1602液晶屏

●    4 * 4薄膜矩阵键盘

●    复位开关

●    电位器

●    9伏电池

●    面包板和连接导线

源代码

程序基于Arduino UNO开发板，使用Arduino语言完成。您需要为键盘添加一个额外的Arduino库文件，如#include <Keypad.h>。因此，请从adafruit库下载此文件。组装后，只需将源代码上传到Arduino Uno开发板中，就可以享受基于Arduino的计算器。

1. #include <Keypad.h>
   
2. #include <LiquidCrystal.h>
   
3. 
   
4. // 1. LCD Pins
   
5. LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
   
6. 
   
7. // 2. Keypad Pins
   
8. const byte Rows = 4;
   
9. const byte Cols = 4;
   
10. char keys[Rows][Cols] =
    
11. {
    
12. {'1', '2', '3', '+'},
    
13. {'4', '5', '6', '-'},
    
14. {'7', '8', '9', '*'},
    
15. {'C', '0', '=', '/'}
    
16. };
    
17. byte rowPins[Rows] = {A2, A3, A4, A5};
    
18. byte colPins[Cols] = {2, 3, 4, 5};
    
19. Keypad customKeypad = Keypad(makeKeymap(keys), rowPins, colPins, Rows, Cols);
    
20. 
    
21. // 3. Dot Button
    
22. int dot = A0;
    
23. int dotFlag = 0;
    
24. int dotButton = 0;
    
25. 
    
26. // 4. Calculator Operators
    
27. float num1, num2, fraction;
    
28. float total;
    
29. char operation, button;
    
30. 
    
31. // 5. Loading Setup
    
32. char input[16];
    
33. int n = 1750;
    
34. 
    
35. void setup()
    
36. {
    
37. // Initialize dot button as input to Arduino
    
38. pinMode(dot, INPUT);
    
39. 
    
40. // Initialize LCD Size
    
41. lcd.begin(16, 2);
    
42. 
    
43. // LCD Loading Setup Begin
    
44. lcd.clear();
    
45. lcd.setCursor(3, 0);
    
46. lcd.print("LOADING...");
    
47. for (int i = 0; i < 16; i++)
    
48. {
    
49. lcd.setCursor(i, 1);
    
50. lcd.write(255);
    
51. delay(50);
    
52. }
    
53. lcd.clear();
    
54. lcd.setCursor(1, 0);
    
55. lcd.print("Simple Arduino");
    
56. lcd.setCursor(3, 1);
    
57. lcd.print("Calculator");
    
58. delay(n);
    
59. lcd.clear();
    
60. lcd.setCursor(0, 0);
    
61. lcd.print("Designed By");
    
62. lcd.setCursor(2, 1);
    
63. lcd.print("Alex Newton");
    
64. delay(n);
    
65. lcd.clear();
    
66. lcd.setCursor(1, 0);
    
67. lcd.print("Alex Newton");
    
68. lcd.setCursor(2, 1);
    
69. lcd.print("how2electronics.com");
    
70. delay(n);
    
71. lcd.clear();
    
72. lcd.setCursor(1, 0);
    
73. lcd.print("Alex Newton");
    
74. lcd.setCursor(2, 1);
    
75. lcd.print("how2electronics.com");
    
76. delay(n);
    
77. lcd.clear();
    
78. // LCD Loading Setup End
    
79. }
    
80. void loop()
    
81. {
    
82. // First while loop for num1.
    
83. while (1)
    
84. {
    
85. dotButton = digitalRead(dot);
    
86. button = customKeypad.getKey();
    
87. if (button == 'C')
    
88. {
    
89. dotFlag = 0;
    
90. num1 = 0;
    
91. num2 = 0;
    
92. fraction = 0;
    
93. total = 0;
    
94. operation = 0;
    
95. lcd.clear();
    
96. }
    
97. else if (dotButton == LOW)
    
98. {
    
99. dotFlag = 1;
    
100. }
     
101. else if (button >= '0' && button <= '9')
     
102. {
     
103. if (dotFlag == 0)
     
104. {
     
105. num1 = num1 * 10 + (button - '0');
     
106. lcd.setCursor(0, 0);
     
107. lcd.print(num1);
     
108. }
     
109. else if (dotFlag == 1)
     
110. {
     
111. fraction = (button - '0');
     
112. num1 = num1 + (fraction / 10);
     
113. lcd.setCursor(0, 0);
     
114. lcd.print(num1);
     
115. dotFlag++;
     
116. }
     
117. else if (dotFlag == 2)
     
118. {
     
119. fraction = (button - '0');
     
120. num1 = num1 + (fraction / 100);
     
121. lcd.setCursor(0, 0);
     
122. lcd.print(num1);
     
123. dotFlag++;
     
124. }
     
125. }
     
126. else if (button == '-' || button == '+' || button == '*' || button == '/')
     
127. {
     
128. operation = button;
     
129. dotFlag = 0;
     
130. lcd.setCursor(0, 1);
     
131. lcd.print(operation);
     
132. break;
     
133. }
     
134. }
     
135. // Second while loop for num2.
     
136. while (1)
     
137. {
     
138. dotButton = digitalRead(dot);
     
139. button = customKeypad.getKey();
     
140. if (button == 'C')
     
141. {
     
142. dotFlag = 0;
     
143. num1 = 0;
     
144. num2 = 0;
     
145. fraction = 0;
     
146. total = 0;
     
147. operation = 0;
     
148. lcd.clear();
     
149. break;
     
150. }
     
151. else if (dotButton == LOW)
     
152. {
     
153. dotFlag = 1;
     
154. }
     
155. else if (button >= '0' && button <= '9')
     
156. {
     
157. if (dotFlag == 0)
     
158. {
     
159. num2 = num2 * 10 + (button - '0');
     
160. lcd.setCursor(1, 1);
     
161. lcd.print(num2);
     
162. }
     
163. else if (dotFlag == 1)
     
164. {
     
165. fraction = (button - '0');
     
166. num2 = num2 + (fraction / 10);
     
167. lcd.setCursor(1, 1);
     
168. lcd.print(num2);
     
169. dotFlag++;
     
170. }
     
171. else if (dotFlag == 2)
     
172. {
     
173. fraction = (button - '0');
     
174. num2 = num2 + (fraction / 100);
     
175. lcd.setCursor(1, 1);
     
176. lcd.print(num2);
     
177. dotFlag++;
     
178. }
     
179. }
     
180. if (button == '=')
     
181. {
     
182. domath();
     
183. break;
     
184. }
     
185. }
     
186. // Third while loop for ensuring C button is executed after while loop 2.
     
187. while (1)
     
188. {
     
189. button = customKeypad.getKey();
     
190. if (button == 'C')
     
191. {
     
192. dotFlag = 0;
     
193. num1 = 0;
     
194. num2 = 0;
     
195. fraction = 0;
     
196. total = 0;
     
197. operation = 0;
     
198. lcd.clear();
     
199. break;
     
200. }
     
201. }
     
202. }
     
203. void domath()
     
204. {
     
205. switch (operation)
     
206. {
     
207. case '+':
     
208. total = num1 + num2;
     
209. break;
     
210. case '-':
     
211. total = num1 - num2;
     
212. break;
     
213. case '/':
     
214. total = num1 / num2;
     
215. break;
     
216. case '*':
     
217. total = num1 * num2;
     
218. break;
     
219. }
     
220. lcd.print('=');
     
221. if (operation == '/' && num2 == 0)
     
222. {
     
223. lcd.print("ERROR 0 DIV");
     
224. }
     
225. else
     
226. {
     
227. lcd.print(total);
     
228. }
     
229. }

复制代码

为什么没显示

我也按照这个方法 不显示数字