RF電路 兩片板子不接同一台PC 傳輸距離變得很短

kaiwen789

前情提要：
我想要設計微波電路，讓兩片Arduino板子可以溝通 (我是用Uno)
目前買了這個東西 http://tinyurl.com/k54ehem (益眾科技 - 27MHz ASK RF 數據傳輸模組  型號A06-0001)
然後利用 http://www.glacialwanderer.com/hobbyrobotics/?p=291 的程式及電路
我把兩片Arduino板子用USB連接線，接在同一台PC上，工作狀況良好
有超過1.5公尺的傳輸距離 ((因為我USB線長度有限，不知道更大可以多少

目前問題：
但是，如果我把其中一片Arduino板子的供電改為 "另一台電腦" 或是 "電池"
他的傳輸距離就會突然變得超級短，大概只有10公分以內
我另外再接了一條50歐姆、一公尺的傳輸線之後，才大概有一公尺半的傳輸距離
想請問有沒有人知道這是怎麼樣的狀況呢?


先謝謝大家指教!!!!!



隨文附上使用的 Code


主程式

1. // Maurice Ribble
   
2. // 8-30-2009
   
3. // http://www.glacialwanderer.com/hobbyrobotics
   
4. // Used Arduino 0017
   
5. // This is a simple test app for some cheap RF transmitter and receiver hardware.
   
6. // RF Transmitter: http://www.sparkfun.com/commerce/product_info.php?products_id=8945
   
7. // RF Receiver: http://www.sparkfun.com/commerce/product_info.php?products_id=8948
   
8. 
   
9. // This says whether you are building the transmistor or reciever.
   
10. // Only one of these should be defined.
    
11. //#define TRANSMITTER
    
12. #define RECEIVER
    
13. 
    
14. // Arduino digital pins
    
15. #define BUTTON_PIN  2
    
16. #define LED_PIN     13
    
17. 
    
18. // Button hardware is setup so the button goes LOW when pressed
    
19. #define BUTTON_PRESSED LOW
    
20. #define BUTTON_NOT_PRESSED HIGH
    
21. 
    
22. void setup()
    
23. {
    
24.   pinMode(BUTTON_PIN, INPUT);
    
25.   pinMode(LED_PIN, OUTPUT);
    
26.   digitalWrite(LED_PIN, LOW);
    
27. 
    
28.   Serial.begin(300);  // Hardware supports up to 2400, but 1200 gives longer range
    
29. }
    
30. 
    
31. #ifdef TRANSMITTER
    
32. void loop()
    
33. {
    
34.   static int prev_button = BUTTON_NOT_PRESSED;  // Previous button press value
    
35.   int        cur_button;                        // Current button press value
    
36. 
    
37.   cur_button = digitalRead(BUTTON_PIN);
    
38. 
    
39.   if ((prev_button == BUTTON_NOT_PRESSED) && (cur_button == BUTTON_PRESSED))
    
40.   {
    
41.     writeUInt(271); // Put any number you want to send here (71 is just a test)
    
42.   }
    
43. 
    
44.   delay(50); // Debounce button
    
45.   prev_button = cur_button;
    
46. }
    
47. #endif //TRANSMITTER
    
48. 
    
49. #ifdef RECEIVER
    
50. void loop()
    
51. {
    
52.   boolean light_led = false;
    
53. 
    
54.   if (readUInt(true) == 271) // Check to see if we got the 71 test number
    
55.   {
    
56.     light_led = true;
    
57.   }
    
58.   
    
59.   if (light_led)
    
60.   {
    
61.     digitalWrite(LED_PIN, HIGH);
    
62.     delay(1000);
    
63.     digitalWrite(LED_PIN, LOW);
    
64.   }
    
65. }
    
66. #endif //RECEIVER
    

複製代碼

Error_Catching

1. // Maurice Ribble
   
2. // 8-30-2009
   
3. // http://www.glacialwanderer.com/hobbyrobotics
   
4. // Used Arduino 0017
   
5. // This does does some error checking to try to make sure the receiver on this one way RF
   
6. //  serial link doesn't repond to garbage
   
7. 
   
8. #define NETWORK_SIG_SIZE 3
   
9. 
   
10. #define VAL_SIZE         2
    
11. #define CHECKSUM_SIZE    1
    
12. #define PACKET_SIZE      (NETWORK_SIG_SIZE + VAL_SIZE + CHECKSUM_SIZE)
    
13. 
    
14. // The network address byte and can be change if you want to run different devices in proximity to each other without interfearance
    
15. #define NET_ADDR 5
    
16. 
    
17. const byte g_network_sig[NETWORK_SIG_SIZE] = {0x8F, 0xAA, NET_ADDR};  // Few bytes used to initiate a transfer
    
18. 
    
19. // Sends an unsigned int over the RF network
    
20. void writeUInt(unsigned int val)
    
21. {
    
22.   byte checksum = (val/256) ^ (val&0xFF);
    
23.   Serial.write(0xF0);  // This gets reciever in sync with transmitter
    
24.   Serial.write(g_network_sig, NETWORK_SIG_SIZE);
    
25.   Serial.write((byte*)&val, VAL_SIZE);
    
26.   Serial.write(checksum); //CHECKSUM_SIZE
    
27. }
    
28. 
    
29. // Receives an unsigned int over the RF network
    
30. unsigned int readUInt(bool wait)
    
31. {
    
32.   int pos = 0;          // Position in the network signature
    
33.   unsigned int val;     // Value of the unsigned int
    
34.   byte c = 0;           // Current byte
    
35.   
    
36.   if((Serial.available() < PACKET_SIZE) && (wait == false))
    
37.   {
    
38.     return 0xFFFF;
    
39.   }
    
40.   
    
41.   while(pos < NETWORK_SIG_SIZE)
    
42.   {
    
43.     while(Serial.available() == 0); // Wait until something is avalible
    
44.     c = Serial.read();
    
45. 
    
46.     if (c == g_network_sig[pos])
    
47.     {
    
48.       if (pos == NETWORK_SIG_SIZE-1)
    
49.       {
    
50.         byte checksum;
    
51. 
    
52.         while(Serial.available() < VAL_SIZE + CHECKSUM_SIZE); // Wait until something is avalible
    
53.         val      =  Serial.read();
    
54.         val      += ((unsigned int)Serial.read())*256;
    
55.         checksum =  Serial.read();
    
56.         
    
57.         if (checksum != ((val/256) ^ (val&0xFF)))
    
58.         {
    
59.           // Checksum failed
    
60.           pos = -1;
    
61.         }
    
62.       }
    
63.       ++pos;
    
64.     }
    
65.     else if (c == g_network_sig[0])
    
66.     {
    
67.       pos = 1;
    
68.     }
    
69.     else
    
70.     {
    
71.       pos = 0;
    
72.       if (!wait)
    
73.       {
    
74.         return 0xFFFF;
    
75.       }
    
76.     }
    
77.   }
    
78.   return val;
    
79. }

複製代碼

vegewell

回復 1# kaiwen789

>>想請問有沒有人知道這是怎麼樣的狀況呢?
會不會是電力不足?
另外地線有沒有連接也要考慮

kaiwen789

呼我自己解決了XD
我想應該是Phase Lock Loop的問題

我原本以為是微波的Phase Lock
但後來想想微波應該是在接收器上面就有做Phase Lock
所以應該是電路Clock的Phase Lock

總之解法就是改用下方這個網站的函式庫就解決了XD
http://www.airspayce.com/mikem/arduino/

也謝謝vegewell網友的回覆=P