ESP8266 Community Forum

- Fri May 24, 2019 3:30 pm #82466 First I want to use my first post to thank Barnabybear for posting his idea!

I've been using a similar circuit on a few li-ion powered esp8266 pir sensors for a few years, and they are working great... about 1yr life with a Vbatt divider too!

That said, I recently built a micro amp meter project and started playing around with the AM312 pir sensors. The AM312 only draws 15uA both active and inactive, compared to the usual hc-sr501 which burns 35uA inactive, and 77uA active. I'm sure I'm not the first to try to retrofit an am312 to this circuit and find out it doesn't work. I looked with my oscope and sure enough the am312 output is just too weak to drive the resistors & diode.

This can be fixed with a pfet or non-inverting buffer. I should've probably gone the pfet route to save myself from challenging solder work, but I fell in love with the small ground current of newer CMOS buffers. So I ordered some NL17SG17 schmitt buffers and dead bug soldered them to the AM312, after cutting the output trace (between the output resistor and output pin). I cut the trace so I could still use the original pins for wiring to 3v3 and the diode circuit, but there's other ways to do it I suppose. After testing, yep... 15uA idle current and the signal is a solid 0-3v3 output @5mA... now the AM312 drives the wake circuit with ease!

Here is an image I made of the wiring/soldering:


Next I'll have to read up on the esp8266 a0 impedance, and see if I can tweak the Vbatt divider for minimum current... regardless, I recommend anyone who is after more battery life from an ESP/PIR node, give this AM312 mod a shot.

Cheers,
Kev

- Tue Apr 14, 2020 2:06 pm #86546 Hello.

I tested the CH_PD with GPIO option for a battery button.
If i set the GPIO to LOW the ESP-07 switched off, but not 100%
The on board LED light a little bit, and the current is like use of ESP.deepsleep(0)
If i made this by myself, pulling out the CH_PD cable, current is very low and LED off.

ESP.deepsleep = 0,015mA
CH_PD off with GPIO = 0,020mA
CH_PD off by pull the wire = very very low 0,002mA ? I forgot the value.

Then i see the problem is if CH_PD will set to GND, like with an resistor.
So i think if i set an GPIO pin to LOW it will set to GND ?

At the first pages here i see an example with to AA batteries, an diode and resistor.
But will it really work ? Anyone test the current to ESP.deepsleep?
Or is there a different between ESP-01 and ESP-07 ?

At the moment i use ESP.deepsleep(0) and connect an button to the RESET pin.
But two AA batteries (akkus) will be to fast empty

- Fri May 22, 2020 4:14 pm #87260 Hello, I don't have any sensor, no capacitor and no diode. I just have 2 resistors, 2 leds, NodeMCU 12E bord, jumper wires and breadboard. Can I make simulation of this project with that. I am not good with connections. Thanks

- Sun Nov 14, 2021 7:08 am #92828 Hello everyone,
Tried this circuit and it works fine, great work, thank you.
I'm planning to use this a a door / window open sensor. I used a reed switch (3 legged ones) instead of PIR so when the magnet goes away ESP gets powered and sends the data to MQTT server, so far so good. But as long as the door or window stays open, ESP also stays awake and this is not for batteries. I tried to send ESP to deep sleep with code and it goes to sleep perfectly, but cannot wake up back when I power up the chip, I need to reset it.
So I would be really greteful if you can share your opinions how to cut the power or wake ESP in my situation.
I didn't change the code or added anything more to circuit, just removed PIR and added a reed switch between VCC and diode. I used 3 legged ones so when the magnet is near, reed is open and ESP is out of power.
Thank you very much.