New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-)
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@andredts the voltage reference only has limited accuracy, therefore the reported battery voltage might vary slightly. Also the load on the battery can change, causing a variation in battery level reported. Not a lot you can do about that I'm afraid.
I experimented with sending all decreases in battery level wrt the previous value, and only large increases (eg 10% or more to detect change of batteries). Works quite well.@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
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@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
@andredts cr2032 is a totally different story. The voltage level fluctuates significantly when sending messages compared to AA powered sensors.
The 10% is only an example value and used for an increasing voltage level (that normally should only happen when replacing batteries). For a decreasing voltage (regular battery usage) you can just report the level and get much higher resolution. Question is if it will really be useful for cr2032 though... -
How about storing last 10 values and send an average every time?
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@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
@andredts said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
For having consistent measurements with a CR2032 you should measure voltage as first action after waking up from sleep.
I keep the value in a variable and process it after "action" message of the node.If possible, run at 1Mhz on internal oscillator so the power consumption of the atmega stays very low (around 1mA instead of 3 at 8MHz/3V).
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@andredts cr2032 is a totally different story. The voltage level fluctuates significantly when sending messages compared to AA powered sensors.
The 10% is only an example value and used for an increasing voltage level (that normally should only happen when replacing batteries). For a decreasing voltage (regular battery usage) you can just report the level and get much higher resolution. Question is if it will really be useful for cr2032 though...@Yveaux I know about that fluctuation, but for my use in a scene controller I would be happy just to know the battery is low. I have it running with a multi-button, were I have click, duble-click and click and hold, I only check battery at one click, because of its fluctuation, but if you use it more than 4 times e a short period that fluctuation is noted, and that is why a added to the 10% increase a 10% decrease gap on battery sent information. Thanks
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@andredts said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
For having consistent measurements with a CR2032 you should measure voltage as first action after waking up from sleep.
I keep the value in a variable and process it after "action" message of the node.If possible, run at 1Mhz on internal oscillator so the power consumption of the atmega stays very low (around 1mA instead of 3 at 8MHz/3V).
@Nca78 said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@andredts said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
For having consistent measurements with a CR2032 you should measure voltage as first action after waking up from sleep.
I keep the value in a variable and process it after "action" message of the node.If possible, run at 1Mhz on internal oscillator so the power consumption of the atmega stays very low (around 1mA instead of 3 at 8MHz/3V).
Hi, I do read the battery first thing after wake up, my problem was when a had various click too close together. It`s good now that I only send battery values that a 10% higher or lower than my last stored value. I will take a look on the 1Mhz bootloader. Thanks
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@Nca78 said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@andredts said in New library to read Arduino VCC supply level without resistors for battery powered sensor nodes that do not use a voltage regulator but connect directly to the batteries ;-):
@Yveaux Thanks, that was exactly the insight I was looking, for my door sensor with 2aa battery, your way worked great. For a scene controller with a CR2032 a had to not send also decreases greater then 10%, but hey, 10 steps is more enough.
For having consistent measurements with a CR2032 you should measure voltage as first action after waking up from sleep.
I keep the value in a variable and process it after "action" message of the node.If possible, run at 1Mhz on internal oscillator so the power consumption of the atmega stays very low (around 1mA instead of 3 at 8MHz/3V).
Hi, I do read the battery first thing after wake up, my problem was when a had various click too close together. It`s good now that I only send battery values that a 10% higher or lower than my last stored value. I will take a look on the 1Mhz bootloader. Thanks
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is it normal that just swapping a pro mini I am getting a voltage reading difference of 0.12V from same node?
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Hi guys, I plan to use a battery powered temperature sensor - 2xAAA batteries i.e. 3V plus a cheap thermistor with a series resistor. I think I shall use the internal 1.1V reference with a resistor divider like 1Meg and 470K to measure the battery level.
But ... I think I can use two Arduino pins configured as outputs (one output would be HIGH and another would be LOW) to connect the resistor divider instead of connecting the divider directly to VCC and GND - this way the resistor divider would draw current only when the sensor is awake and thus saving power. It would be more simple than using an external transistor to enable the resistor divider.
Same goes for the temperature measurement, use another pair of pins configured as outputs to connect the thermistor and the series resistor.
I have tested this idea using the Nodemanager "setPowerPins" function, I can easily measure temperature this way and draw current only when the sensor is awake. After making the measurements all outputs are set LOW (no resistor divider can draw current) then I put sensor to sleep.
What is your opinion? Is there any "weakness" in this idea? -
Hi guys, I plan to use a battery powered temperature sensor - 2xAAA batteries i.e. 3V plus a cheap thermistor with a series resistor. I think I shall use the internal 1.1V reference with a resistor divider like 1Meg and 470K to measure the battery level.
But ... I think I can use two Arduino pins configured as outputs (one output would be HIGH and another would be LOW) to connect the resistor divider instead of connecting the divider directly to VCC and GND - this way the resistor divider would draw current only when the sensor is awake and thus saving power. It would be more simple than using an external transistor to enable the resistor divider.
Same goes for the temperature measurement, use another pair of pins configured as outputs to connect the thermistor and the series resistor.
I have tested this idea using the Nodemanager "setPowerPins" function, I can easily measure temperature this way and draw current only when the sensor is awake. After making the measurements all outputs are set LOW (no resistor divider can draw current) then I put sensor to sleep.
What is your opinion? Is there any "weakness" in this idea?
