This blog post explains the easiest way of powering up the ESP32-CAM board: Connecting an external power supply to the input voltage pin 5V on the board.
On the ESP32-CAM board, the soldered voltage regulator AMS1117-3.3 (read more about the AMS1117-3.3 here) regulates the voltage connected on the input voltage pin 5V. It delivers an output voltage of 3.3 volts and a maximum current of 1.5 amperes. To this end, the voltage regulator requires an input voltage greater than 4.5 volts due to a dropout voltage of 1 volt. In detail, both a laboratory power supply or a battery-based power supply can deliver the required input voltage.
Laboratory Power Supply
The function of a laboratory power supply is to supply a constant voltage (typically indicated by „C.V.“) or a constant current (typically indicated by „C.C.“). It converts an unregulated alternating current (AC) into a constant direct current (DC). Usually, a laboratory power supply delivers a variety of continuous or preset voltages (read more about regulated power supply on Wikipedia).
Now, it is time to power up the ESP32-CAM board with a laboratory power supply that delivers the constant voltage required:
- Set the output voltage of the laboratory power supply to a fixed voltage between 5 volts and 6 volts
- Connect the output voltage of the power supply to a ground pin GND and the input voltage pin 5V
- Turn on the voltage supply of the laboratory power supply to provide the required input voltage of greater than 4.5 volts to the AMS1117-3.3
That’s it. The external power supply together with the AMS1117-3.3 power up the ESP32-CAM board.
Battery-based Power Supply
A battery-based power supply delivers an output voltage, depending on the type of the battery. For instance, a Lithium-Ion Polymer (LiPo) battery delivers an output voltage of 4.2 volt, if it is fully-charged. While discharging, the supplied output voltage decreases to 3.7 volts. Please note that the output voltage of a LiPo battery should not reach 2.5 volts or less – better 3 volts or less. Otherwise, it could permanently damage the LiPo battery:
Due to the required input voltage of greater than 4.5 volts, the number of needed LiPo batteries is two LiPo batteries connected in series:
In detail, two fully-charged LiPo batteries connected in series supply an output voltage of 8.4 volts to the AMS1117-3.3, powering up the ESP32-CAM board. While discharging, the two LiPo batteries supply an output voltage of 7.4 volts, decreasing to an output voltage of 5 volts. To prevent the two LiPo batteries from a permanently damage, completely disconnect the two LiPo batteries from the electrical circuit, latest reaching the critical low voltage of 5 volts – better 6 volts.
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