ESP-12_onBatt_01

The use of the relatively “new” and absolutely  “cheap” ESP8266 IC generates a rush in the apparition of new IoT  applications.

Lately I’m looking for devices that can run on batteries for months.

A device inside my mailbox twittering when the door was opened.

A moisture sensor reporting every hour from a spot in the garden, sending the data to ThingSpeak .

A tank level sensor reporting when low critical level is reached.

etc…

Working with Energía and the Texas Intrument’s Launchpads found the EnergyTrace tool.

How EnergyTrace measure power?
A software controlled DC-DC converter generates the target power supply (1.2 V-3.6 V).
The time density of the DC-DC converter charge pulses equals the energy consumption of the target microcontroller.
A built-in calibration circuit defines the energy equivalent for a single charge pulse.
The width of pulses remains constant. By counting  the charge pulses during a period of timed the average current is calculated.

BatteryLife

By removing the jumper of 3.3V to the development section and connecting my ESP8266 based device the EnergyTrace can be used to estimate the battery life.

MSP432_EnergyMonitor

 

My  approach for the battery  power is to use a LDO regulator with very low quiescent current and 3 AA alkaline batteries.

regulator4

To reduce power the power-on LED and the light sensor LDR were removed.

The RGB led and some other resistors were also removed.

ESP12_Sleep_3xAA_02

Finally the module worked for 4 months and 7 days !!!

ESP12_Sleep_3xAA_02-02

This post is in construction….

blogger-at-work

Advertisements