12 V to 5 & 3.3 V regulator issue with Arduino and ESP8266

Question

I built an electronic circuit that uses the Arduino IC (ATmega328P-PU) IC, and the ESP8266. I moved out the IC Circuit from the Arduino Board, and moved it into my own board, so that I could free myself from using the Arduino system, just using the IC.

The system that I am building has 4 water sensors and will trigger a web request when the sensor is triggered.

Everything works OK when I use the 5V and the 3.3V regulator built into the Arduino Board, but when I build my own, the 5V starts to get too hot very quickly. I know that the ESP8266 uses a lot of electricity, but I don't know how to support it with my current regulator setup. Also, usually about 3 seconds into it being powered on using a 12V power supply, it will stop working all together.

Note: I basically did moved my IC Board much like this: https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard

The Parts that I am using are as follows:

• Addicore 5V 1.5A Positive Voltage Regulator L7805CV in Antistatic Foam (5pcs)
• 5pcs Addicore 3.3V 950mA LD33V LD1117V33 Voltage Regulator in Antistatic Foam
• 3-pack NEW Atmega328p-pu Chip w/ Arduino UNO Bootloader
• Makerfire 4pcs ESP8266 Serial Wireless Wifi Transceiver Module Esp-01
• 100 Pcs 6 x 11mm 100uF 25V Radial Aluminum Electrolytic Capacitors

Here is my circuits.io, it has the setup and the code: https://circuits.io/circuits/2554003-button-press-wifi-with-esp8266/

R1: 10k
R2: 1k
R3: 2k
R3: 220
C1: 100u 20v
C2: 100u 20v

My basic and wiring schema for the ESP8266 setup is like this: http://www.martyncurrey.com/arduino-to-esp8266-serial-commincation/

Again, it works GREAT when the breadboard's power is using the Arduino's built in power regulator.

Also, please note, that I just tried this too, and everything wanted to start burning up just as it would have before: http://electronics-diy.com/3.3v-and-5v-power-supply.php

My question is: what am I doing wrong?

Answer 1

You connected your 3.3V regulator wrong.

Its pinout, as seen from the front, is Gnd/Vout/Vin:

You connected it as Vout/Gnd/Vin. Since its Vout is connected to ground, it's likely the regulator is passing its maximum current straight to ground. The same current also has to go through the 5V regulator, which has to drop at least 7V, resulting in a large power dissipation and the regulator getting too hot.

Also, neither your circuit diagram nor your wiring diagram show a ground connection between your power circuit and the rest of your circuit; your esp8266 will never work that way.

Answer 2

Figure 1. A few problems stand out.

Everything becomes much clearer on the schematic.

1. The GND connection is "powering" U1 while the 3.3 V OUT connection is tied to GND. This isn't going to work well.
2. There is only one wire from the power circuit to the rest of the circuit so there is no return path to the power supply. You need a link as shown by the green line.

Answer 3

You should have some small 0.1uF or 0.22uF caps bypassing both the input and the output of the regulators to ground or they can start to oscillate. If you're drawing more than a few tens of milliamps or so out of the 7805, it is going to get hot without a heat sink. The higher P1 is, the hotter it will get.