Author Topic: Reading Battery with out DC-DC converter.. (Battery use only)  (Read 285 times)


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Reading Battery with out DC-DC converter.. (Battery use only)
« on: August 18, 2017, 08:08:41 AM »
Figured I asked after looking over the forum.
I have decided to drop the DC-DC converter that is used to supply the Simblee with 3.3v while on batteries...  Used it for powering LEDs etc.
But the trade off of being in ULP and the device proved that it would draw around 10ma or more in idle and goes up as the batteries sour.

So I'm now using just using batteries (2 AA's) to power the Simblee and knowing that the Simble stops around 1.8volts, I need to do a warning (LED) to have batteries replaced (2.2v or so).
The warning will be a red led on the sender (Footswitch) and on the receiver.  The receiver will store the  last condition to display if power off and on again and will update when fresh batteries are installed.

The one option I'm using is the one posted long ago.. by mkay

analogReference(VBG); // Sets the Reference to 1.2V band gap           
analogSelection(VDD_1_3_PS);  //Selects VDD with 1/3 prescaling as the analog source
int sensorValue = analogRead(1); // the pin has no meaning, it uses VDD pin
float batteryVoltage = sensorValue * (3.6 / 1023.0); // convert value to voltage

But the data differs as it is reporting.

If not, I will stay with this and just trigger the LED using it.

I do like the 400na draw in Simblee OFF .. And the fast response when active.

And I see that if you have the serial connected, it causes resets..