I am trying to make my ESP8266 to open the door in my building through a buzzer (intercom). There are two contacts, and when you close them, it opens the door downstairs.
The buzzer also have voice-intercom capabilities. To power the whole thing, there is 12V power supply. I decided to hookup ESP8266 directly to it (through VIN/Ground pins).
The problem is when I hook up my ESP8266, it doesn't power on, and I see the voltage drop from 12V to 1.4V. I don't understand what causes it.
The buzzer's power supply shows 12V with 1.4 Amps which should be more than enough for the ESP8266 to power on.
Do you guys any ideas or tips I could try to figure it out?
The problem is when I hook up my ESP8266, it doesn't power on, and I see the voltage drop from 12V to 1.4V. I don't understand what causes it.
It means that something is drawing more current than the power supply can give.
Now why that is is hard to say because you have provided no real technical information like a schematic showing how everything is wired up. Words don’t cut it in electronics.
To power the whole thing, there is 12V power supply.
Is it a DC power supply because sometimes these things use a 12V AC supply.
So you have a bare ESP8266 and you have connected it to 12V? They are designed to run off 3V3, not 12V.
I suspect you don't have a bare ESP8266 but one on a board of some kind. At the very least we need to know exactly what you have and a schematic, hand drawn and photographed is fine, a list of things connected to other things is not fine.
Just to check but when you measure current on a meter you do not wire it up like when you measure voltage.
To measure the current you must break the circuit you are trying to measure and put the meter into the break. The meter then acts like the piece of missing wire to compleat the circuit. It looks like you were not doing that from your photograph. Also most digital meters require you to use a different socket on the front of the meter than you use when measuring voltage.
According to this source you can power up ESP8266 through VIN pin with up to 12V input.
You are confusing ESP8266 with a board based on an ESP8266 and talking about them as if they are the same thing. Further you are talking about all different ESP8266 based boards as if they are the same thing. The only reference I can see on that page to powering a board with 12V does NOT say you can power an ESP8266 with 12V it actually says:
1 pin marked as VIN provides 5V and can power the whole NodeMCU between 7V-12V with up to 1A
I checked all the ESP8266 boards I have and none are designed to be powered from 12V, they are designed for 5V or 3V3.
I think most likely you fried your board, power it from the USB port and see if it works.
(12-3.3)*0.1A= 0.87watt dissipated by the onboard regulator.
More if you power something else from the module.
That could make it very very hot, because it has limited heatsinking, depending on room temp and airflow.
Probably not good for the lifespan of the module.
Don't blindly believe the product information, or the posters here.
Feel for yourself after 20 minutes or so.
Leo..
But I also have ESP32 which according to this.....
See the silver rectangle at the top, that is an ESP32. It is sitting on an ESP32 development board. So you do not have an "ESP32", you have an "ESP32 dev kit". That makes all the difference as to what voltage it will take.
I could buy and hook up an external voltage regulator to reduce the voltage 12V to ~3.3V.
But the problem with voltage drop from 12V to 1.5V is still a mystery to me.
Thank you guys for all your inputs btw! I really appreciate your time and help
So, the elephant in the room... Who says that the intercom can supply enough current? You've probably just overloaded it, or connected to something in the circuit that isn't actually the power supply...
Although, I'm seeing now that the possibility was mentioned in reply #1.
What convinces you that those terminals are in fact, a power supply connection?
You are not measuring current correctly (already pointed out). Further, your meter appears from the pictures to be on a 2mA (two milliamperes) scale. If it is 1.5mA and 12volts, there is a resistor (not far away from 10k) between the measuring points and the power supply.
I went through Lee Dan intercom specs and schematics and found out, none of those wires are designed to supply any power. If you close connection between any of them, it will activate one of the features: talking, listening and opening the door. So, there is no luck there.
On the other hand, I powered my ESP8266 with a power bank, and introduced a relay that closes connection to open the door. Hooked it up with my HomeAssistant instance, and now I can open the door remotely using Siri
The problem is there is no wall plug near the intercom, so I need to think about that. Also there are more wires that are not used in the intercom, I'll keep looking at the schematics to see what they are for and if any of them can be used.
Let's see!
Again, thank you so much for all your valuable input! I am pretty bad electrical engineer, and should brush up my physics basics.
