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Questions tagged [nodemcu]

For questions about the NodeMCU open-source Internet of Things (IoT) platform. Use in conjunction with the "iot" tag.

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how to detect water level using NodeMCU in overhead tank?

I am making a simple water level alarm connected to my V2 NodeMCU. Using the principle of water conductivity. Two wires with stripped ends are dipped into the tank. As soon as the water level reaches ...
jerrymouse's user avatar
1 vote
1 answer

Keeping NodeMCU operating with a super capacitor

Awhile back this post asked about providing 3-4 seconds of power to an NodeMCU subsequenst to a loss of its primary power supply. Prior Post I have a similar need except I only need a split second ...
Next's user avatar
  • 11
1 vote
1 answer

nodemcu/esp8266 reads lower than expected on A0

I got a NodeMCU/ESP8266 development board and am trying to utilise the A0 (10-bit ADC) input to read the voltage from a voltage divider on the 3.3V pin. So I have the following: simulate this circuit ...
Brian's user avatar
  • 71
1 vote
2 answers

How to switch a 12V DC (3A) Motor with a 3.3V signal? [closed]

I was previously using a 2N2222A transistor with a small dc motor and it worked fine. As soon as I used it to control the 3A motor, The circuit stopped working. Is there any way I could control the ...
lakshjaisinghani's user avatar
0 votes
1 answer

how to use an npn as a switch between battery and motor?

I am a noob playing around with nodemcu and esp8266. I am trying to control a motor in an automated air freshener. I had been trying to power the motor with board supply but I gave that idea up when I ...
Antariksha Yelkawar's user avatar
0 votes
1 answer

TP4056 and li ion battery charging that never ends

I have designed a circuit with a Nodemcu ESP8266 (something similar to an arduino nano, requiring 3.3V to work) and I would like to have a backup battery to be robust to main power interruptions. So ...
Desmond's user avatar
  • 103
0 votes
3 answers

Optocouplers vs Voltage Dividers

I have a device that has a terminal that goes to 5v at certain times. I wish to sense that voltage with an ESP32. I have built this circuit using an optocoupler: simulate this circuit – ...
Spammy's user avatar
  • 97