Soft touch power switch (Push on Hold off)
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange users link it as a readable reference schematic for single-button latching power circuits on Arduino and ESP32 projects.
Recommended by 1 people across 1 different months, 2018 to 2019.
What it is
A short demo by Michael Ruppe of a soft touch power switch circuit, where one momentary push button turns a project on and a microcontroller then latches power and can switch it off. The description links Arduino demo code on GitHub and an EEVBlog video on the same idea.
What people said
Recommends Some Guy · 2018-04 · Electrical Engineering Stack Exchange · on “Arduino Self Power Circuit”
I was finally able to find exactly what I was looking for. For anyone looking for info on how to do this, look for "soft touch power switch". This video here explains it well, has a good readable schematic, and is simply implemented: [this video] This setup uses a single momentary switch for both power and input.
Cites rea104 · 2019-06 · Electrical Engineering Stack Exchange · on “Latching power with LDO enable pin”
There are lots of examples of latching circuits that use a single momentary push-button to turn on/off a circuit by combining two or more transistors. Some examples are: Simple soft power latching circuit for a microcontroller [LINK] [LINK] [this video] Since it is common for LiPo-powered devices use an LDO to generate a constant 3.3 V, my question is: can you use the "ENABLE" pin on the LDO to generate that latch from the microcontroller? The general idea would be something like: Push button pulls AP2112 [LINK] LDO EN high LDO powers microcontroller Microcontroller uses LATCH pin to keep LDO EN pin high (this is the latch) Microcontroller can shut-down the whole system when desired by setting LA
Cites csiz · 2019-12 · Electrical Engineering Stack Exchange · on “Can I use a voltage regulator to bring high voltage down to 3.3V GPIO input for ESP32?”
I have a button connected to the power rail of my project and I want to know when it's pressed with an ESP32 chip. Since the input voltage (6.5V to 15V) is higher than the maximum rating of the ESP32 I need to bring it down. Like this video of a power switch circuit [this video] , I used a current limiting resistor of 10K ohm between the button and the chip, relying on the protective diodes of the GPIO pin. But when I measure the voltage it's 4.1V which is still higher then the maximum spec of the ESP32; so I'd like a safer way. Is this circuit using a 3.3V voltage regulator appropriate? I use a 1k ohm resistor to load the voltage regulator, and 2 10uF caps as suggested in the datasheet. The low