eg. ESP32-CAM secure offline video recorder
ESP32-CAM module usually sends digitized video though a Wi-Fi network, which is vulnerable to a hacker attack. The module can also record offline video to a microSD flash memory card, when Wi-Fi network in unavailable, or extra security to prevent tampering with online ESP32-CAM modules is needed. Internet video recorder examples for ESP32-CAM also include Wi-Fi FTP server functionality, which makes the camera vulnerable to a hacker attack, or enables an intruder to locate the camera with a Wi-Fi scanner device. However, a new ESP32-CAM module firmware provides video recording functionality without Wi-Fi connectivity. A simple hardware modification also provides a software controlled micro switch for controlling camera operation. Let’s get to work!
The first task is to disable all Wi-Fi communication, next we are going to add a micro switch button for controlling the camera operation. Go to PC USB Projects Downloads to obtain a new video recording firmware without Wi-Fi functionality and program it into your ESP32-CAM. Now, we are going to add a micro switch control button.
There are no GPIOs left on an ESP32-CAM module, except for the ones used for serial (TTL RS-232) communication, if one decides not to use it for debugging and testing. However, there is also GPIO33 that drives a red LED at the rear side of the module, but GPIO33 is not connected to any of external pins with 2.54 mm spacing. Luckily, GPIO33 pin may be rewired to Vcc pin. The pin originally provides connection to either internal +3.3 V power supply (through AMS1117 regulator), or external (+5 V) power supply that powers AMS1117 regulator. On a new PCB Vcc pin is usually connected to +3.3 V via a zero-ohm resistor. If the latter is removed, GPIO33 may be rewired to Vcc pin. Though the red LED remains connected between +3.3 V power supply via 1 k ohm resistor, it is now possible to add an external switch to the ground through a 330-ohm resistor. The resistor prevents short-circuiting of GPIO33, when GPIO33 is programmed as a digital output and set to a high logical level (+3.3 V). When GPIO33 is programmed as an input the resistor conducts the current through the red LED (which lights up) and assures a low logical level on GPIO33. The extra button is currently used to stop video recording and to close an opened video file. The power may be safely turned off while the button is pressed for a short time, or the button may be released to start a new video file recording.
A setback for running the camera without a Wi-Fi connection is that there are no network time services available and it starts with the default time and date (preset in firmware). This issue will be accessed in the future versions of the firmware. However, ESP32-CAM module will have to be constantly powered to maintain real time clock operation.
ESP32-CAM module modifications. Click to the photo to enlarge it.
ESP32-CAM module modifications. Click to the photo to enlarge it.