Door Window sensor consuming more power when closed
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I have a Door/Window/Switch sensor setup with a reed switch and magnet assembly. When open (magnet moved away) the device consumes 0.20mA, however, when closed the device consumes 0.97mA (uA). Is this normal?
I modified the example to include an INTERRUPT.
// Simple binary switch example // Connect button or door/window reed switch between // digitial I/O pin 3 (BUTTON_PIN below) and GND. #include <MySensor.h> #include <SPI.h> #include <Bounce2.h> #define CHILD_ID 3 #define BUTTON_PIN 3 // Arduino Digital I/O pin for button/reed switch #define INTERRUPT BUTTON_PIN-2 MySensor gw; Bounce debouncer = Bounce(); int oldValue=-1; // Change to V_LIGHT if you use S_LIGHT in presentation below MyMessage msg(CHILD_ID,V_TRIPPED); void setup() { gw.begin(); // Setup the button pinMode(BUTTON_PIN,INPUT); // Activate internal pull-up digitalWrite(BUTTON_PIN,HIGH); // After setting up the button, setup debouncer debouncer.attach(BUTTON_PIN); debouncer.interval(5); // Register binary input sensor to gw (they will be created as child devices) // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. // If S_LIGHT is used, remember to update variable type you send in. See "msg" above. gw.present(CHILD_ID, S_DOOR); } // Check if digital input has changed and send in new value void loop() { debouncer.update(); // Get the update value int value = debouncer.read(); if (value != oldValue) { // Send in the new value gw.send(msg.set(value==HIGH ? 1 : 0)); oldValue = value; gw.sleep(INTERRUPT,CHANGE, 0); } } ```
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@iask (probable cause) You are using the internal pull-up of the Arduino. This is a resistor of around 20 k ohm link. If this is pulled to ground by the reed contact. I = U/R = 5/20.000 = 250 uA = 0.250 mA..
Also: debouncer combined with sleep is guaranteed to give trouble. Sleep does also sleep the internal clock which is used by the debouncer class/ library.
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@AWI thanks for responding. I will look into the internal pull-up. I did had some doubts with the debouncer. For example, putting the line gw.sleep(INTERRUPT,CHANGE, 0); outside of the IF statement caused the sensor to randomly drop messages to the GATEWAY. I did come across a post whereby someone used a delay instead of debouncing
// Short delay to allow buttons to properly settle sensor_node.sleep(5);
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@AWI You are right about that internal pull-up. It got even worse when I added an external pull-up. I placed a 10k between pin 3 and GND (for the Door, Window example) and disabled the internal pull-up. When the reed contact is open the sensor pulls only 008.5 uA which is great! When the reed is closed it pulls a whopping 00.32 mA.
I don't know what else to try to bring down that 00.32mA whenever the reed is closed (which will be most of the time because the window will be closed).
I will look into hardware debouncing to see if that will be a solution for the reed switch.
// Simple binary switch example // Connect button or door/window reed switch between // digitial I/O pin 3 (BUTTON_PIN below) and GND. #include <MySensor.h> #include <SPI.h> #include <Bounce2.h> #define CHILD_ID 3 #define BUTTON_PIN 3 // Arduino Digital I/O pin for button/reed switch #define INTERRUPT BUTTON_PIN-2 MySensor gw; Bounce debouncer = Bounce(); int oldValue=-1; // Change to V_LIGHT if you use S_LIGHT in presentation below MyMessage msg(CHILD_ID,V_TRIPPED); void setup() { gw.begin(); // Setup the button pinMode(BUTTON_PIN,INPUT); // deActivate internal pull-up digitalWrite(BUTTON_PIN,LOW); // After setting up the button, setup debouncer debouncer.attach(BUTTON_PIN); debouncer.interval(5); // Register binary input sensor to gw (they will be created as child devices) // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. // If S_LIGHT is used, remember to update variable type you send in. See "msg" above. gw.present(CHILD_ID, S_DOOR); } // Check if digital input has changed and send in new value void loop() { debouncer.update(); // Get the update value int value = debouncer.read(); if (value != oldValue) { // Send in the new value gw.send(msg.set(value==HIGH ? 1 : 0)); oldValue = value; //Sleep until interrupt comes in on motion sensor. Send update every two minute. //gw.sleep(INTERRUPT,CHANGE, SLEEP_TIME); gw.sleep(INTERRUPT,CHANGE, 0); } }
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@iask try a 1 Mohm pull up and disable the internal. Hardware debounce is the way to go. Add 100nF to ground and 10k in series with the contact.
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I tried that with the code below but it doesn't work at all. It registers the first 0 status with the Gateway and then goes silent.
// Simple binary switch example // Connect button or door/window reed switch between // digitial I/O pin 3 (BUTTON_PIN below) and GND. #include <MySensor.h> #include <SPI.h> //#include <Bounce2.h> #define CHILD_ID 3 #define BUTTON_PIN 3 // Arduino Digital I/O pin for button/reed switch #define INTERRUPT BUTTON_PIN-2 //const byte switchPin = 3; byte oldSwitchState = HIGH; // assume switch open because of pull-up resistor MySensor gw; // Change to V_LIGHT if you use S_LIGHT in presentation below MyMessage msg(CHILD_ID,V_TRIPPED); void setup() { for (byte i = 0; i <= A5; i++) { pinMode (i, INPUT); digitalWrite (i, LOW); } gw.begin(); // Setup the button pinMode(BUTTON_PIN,INPUT); // Activate internal pull-up //digitalWrite(BUTTON_PIN,LOW); // Register binary input sensor to gw (they will be created as child devices) // You can use S_DOOR, S_MOTION or S_LIGHT here depending on your usage. // If S_LIGHT is used, remember to update variable type you send in. See "msg" above. gw.present(CHILD_ID, S_DOOR); } // Check if digital input has changed and send in new value void loop() { // see if switch is open or closed byte switchState = digitalRead (BUTTON_PIN); // has it changed since last time? if (switchState != oldSwitchState) { oldSwitchState = switchState; // remember for next time if (switchState == LOW) { gw.send(msg.set(0)); } else { gw.send(msg.set(1)); } gw.sleep(INTERRUPT,CHANGE, 0); } }
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@iask Are you measuring a transition on the input? You need the external pull-up at minimum.
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@AWI right on! I had some time to go at this again. I realized that I had soldered the pullup on the wrong pin. Right after that my fine 898+ station stopped working. It just wont get hot. Going old school for the next few days.
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@AWI So here is what I got. When the sensor (Reed Switch) is open, the sensor consumes 8.5uA and when closed it consumes 11.5uA.
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I still have the regulator on board
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I removed both LEDS
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I am using hardware debouncing
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Set Analog pins LOW
Were you able to get lower than 11.5uA, with your NRFXXXXX connected, when in sleep mode? I am trying to find a proper benchmark to work with. My sensor is powered with a 3V CR123A battery.
I find that the CR123A is used in sensors by some alarm companies here in the US. See page 10 here (I've seen these things last a long time...3 years in some cases) so I am using this as my battery benchmark for all my sensors. Definitely not the cheepies from China.
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@iask I am not able to measure anything accurate that low. I use the chargeable version of cr123 in many sensors. No long term results yet, but a lot of power
