ESP8266 Community Forum

- Sun Jun 05, 2016 5:26 pm #48642 Hello,

I have several analog sensors (rain, light intensity, distance, ...) that require 5V.
For my projects I prefer battery power with 3.3V and very low deep-sleep current consumption for long lasting battery packs.

If I need 5V I have to use a DC-DC converter.
Such a converter raises my deep-sleep consumption from 0.2uA up to 1mA, this reduces the lifetime a lot.

Is there a best-practice how to handle these analog sensors ?

BR
Gawan

- Sun Jun 05, 2016 5:31 pm #48643 You can use a P-Chan MOSFET to cut their 5V supply during deep-sleep, the gate of this MOSFET would have a pullup and controlled by a N-Chan MOSFET which is controlled by a GPIO along with a pulldown.

- Sun Jun 05, 2016 5:45 pm #48646 I think the problem is not the sensor, but the converter.
I have 1-2mA during deep-sleep even if I disconnect the sensor

- Sun Jun 05, 2016 6:15 pm #48649

I think the problem is not the sensor, but the converter.
I have 1-2mA during deep-sleep even if I disconnect the sensor

That's why you should disconnect the entire DC-DC converter, not just the sensor. Many DC-DC converters already have a shutdown pin, so you may not even need to use a mosfet.
For low current sensors, you may also consider using a charge pump (e.g. MAX619) instead of a switch mode boost converter.