13.6 V to 3.7v/5v DC-DC Step Down to run ESP8266

Thread Starter

ptiwari8

Joined Nov 28, 2020
4
I have a garage door wall button which has 13.6v across. This is the typical wall button most of us have in the our homes to open and close the garage from inside the house. I want to replace the wall button and connect a ESP8266 IoT chip to control from smart phone and this chip only need between 3.3v-5v. I am using a DC-DC buck converter to step down 13.6v to 3.3v. However nothing happening when I connect the buck converter to wires coming from garage motor. When I use the multimeter to measure the voltage across the output of buck converter then the voltage drops to 2.2v which is simply too low and I cannot change it.

Should I be using different type of DC-DC converter to run the 3.3v ESP8266 chip directly using the garage wall button wires? I want to avoid adding batteries and looking for ways to power the IoT chip directly.

Any help or nuggets would be highly appreciated?
 

ElectricSpidey

Joined Dec 2, 2017
1,401
Looks correct to me.

But your original post says " I connect the buck converter to wires coming from garage motor. "

That is not correct.

You need to have the converter connected to the source power, and make sure you crank down the voltage before you connect to the micro, because those things come from the factory with the output near full.

Otherwise you may have a faulty converter or a short circuit.
 

Thread Starter

ptiwari8

Joined Nov 28, 2020
4
Looks correct to me.

But your original post says " I connect the buck converter to wires coming from garage motor. "

That is not correct.

You need to have the converter connected to the source power, and make sure you crank down the voltage before you connect to the micro, because those things come from the factory with the output near full.

Otherwise you may have a faulty converter or a short circuit.
Thank you one more time. Sorry if my original post was clear. Garage door motor usually has two thin wires come out and this connects to a wall button which we push to open and close the garage door. These thin wires have 13.6volts across them. These thin wires are input to my buck converter and as soon as I connect the buck converter I am finding something weird happening. The voltage at both input and output of the buck converted becomes 2.2v and does not change at all no matter how much I turn. Also the LED on the buck converter seems to keep blinking and looks like circuit is getting switched on and off. It seems something happening inside the buck converted as soon as I connect it to 13.6 volts tiny wires. I disconnect the buck converted and put it on another source and it works fine.

I am wondering if anyone has done this type of connection with the garage wall button? Is the buck converted behaving weird due to very low current flowing through the "thin wires" and hence buck converter not functioning properly?
 

ElectricSpidey

Joined Dec 2, 2017
1,401
Those "thin wires" are obviously not connected to the source supply, but connect instead to some circuitry that operates the motor.

The only reason there is 13.6 volts at that connection is because the button is not being pressed.

You must find the source supply to connect the converter to, and those "thin wires" is where you connect the NO relay terminals to operate the motor.
 

Thread Starter

ptiwari8

Joined Nov 28, 2020
4
Those "thin wires" are obviously not connected to the source supply, but connect instead to some circuitry that operates the motor.

The only reason there is 13.6 volts at that connection is because the button is not being pressed.

You must find the source supply to connect the converter to, and those "thin wires" is where you connect the NO relay terminals to operate the motor.
Thank you for the advice. It was really helpful to figure out what is happening but I am still not out of water. I traced the end of the "thin wire" which is for the wall switch button and when unpressed it shows 13.6v. The end of the wire is connected in the base of the garage door circuitry. When I use my multimeter at the end where this "thin wire" is connected I measure a very fluctuating voltage in the range 10-13.6volts. This is constant fluctuation as read by multimeter. This now explains why my buck converter was having the led constantly blink. Now next to this I found another two "thin wire" which are connected to the green light source which detects obstruction in the door and this green light is at the bottom of physical garage door. The end of this light source has a stable voltage of 5.7volts and not fluctuating. I can connect the buck converter to this 5.7volt source and step down to 3.3v for ESP8266 however seems like not enough current to run the ESP8266 as it does not turn on.

Any suggestions if I can use this 5.7volt source to somehow power the ESP8266+relay? Really appreciate your help.
 
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