-
-
Save sabretus/814f12c7dd817ecd67499822ad2d3293 to your computer and use it in GitHub Desktop.
connect arduino to a reed switch to read the water flow from a water meter
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| // this is for an arduino uno. | |
| // this was inspired by http://www.instructables.com/id/Arduino-Reed-Switch/?ALLSTEPS but | |
| // changed to use the arduino internal pull up resistor: | |
| // | |
| // +-----------------+ | |
| // | arduino GND -----reed_switch----\ | |
| // | | | | |
| // | 12 --------------------/ | |
| // +-----------------+ | |
| // | |
| // tested with a window reed switch alike http://www.aliexpress.com/item/New-Arrival-High-Quality-10W-Recessed-Magnetic-Window-Door-Contacts-Alarm-Security-Reed-Switch-Home-Safely/32550780759.html | |
| const int pinReedSwitch = 12; | |
| const int pinLed = 13; | |
| int lastValue; | |
| unsigned long lastValueTime; | |
| unsigned int counter = 0; | |
| void setup() { | |
| // initialize pins. | |
| pinMode(pinReedSwitch, INPUT_PULLUP); | |
| pinMode(pinLed, OUTPUT); | |
| // initialize serial and wait for the port to open. | |
| Serial.begin(19200); | |
| while (!Serial) { | |
| // wait for serial port to connect. | |
| // needed for native USB port only. | |
| } | |
| Serial.println("hello"); | |
| lastValue = !digitalRead(pinReedSwitch); | |
| lastValueTime = millis(); | |
| } | |
| void loop() { | |
| int value = !digitalRead(pinReedSwitch); | |
| if (value != lastValue) { | |
| lastValue = value; | |
| digitalWrite(pinLed, value == HIGH ? HIGH : LOW); | |
| if (value) { | |
| ++counter; | |
| unsigned long valueTime = millis(); | |
| unsigned long timeDifference = valueTime >= lastValueTime | |
| ? valueTime - lastValueTime | |
| : lastValueTime - valueTime; | |
| lastValueTime = valueTime; | |
| Serial.print(counter); | |
| Serial.print(" dt="); | |
| Serial.print(timeDifference); | |
| Serial.print('\n'); | |
| } | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment