What we need for functionality
- ESP32-CAM AI-thinker board with OV2640 camera module here
- Supported camera modules here
- Module board version here
- How to flash binary files to board from Linux/MAC/Windows here
- How to compile software in the Arduino IDE here
- How to reset the configuration to factory settings here
- Status LED here
- Schematic main board is here
- Issue with FLASH LED on the main board here
- External WiFi antenna here
- Power supply here
- External temperature sensor DHT22/DHT11 here
- Potential issue here
Basic information:
- Low cost version
- FLASH LED on the board
- Option connecting external FLASH LED
- Micro SD card slot
- Internal WiFi antenna, after HW modification it's possible connecting external antenna
- Additional HW must be purchased for programming
- 4MB FLASH and 4MB external PSRAM
- 520 KB SRAM
It's a few dollars board with ESP32 MCU and Camera. It's necessary to buy a board with camera module OV2640. The board is sold without a programmer by default. It is possible to program it using the FTDI USB to UART converter, or purchase an official programmer for the board. We recommend purchasing an official programmer. It can save a lot of trouble with connecting and programming the board. There are currently 2 different board versions, but only one is compatible with the official programmer.
In the following picture, we can see the ESP32-CAM board and the programmer for the board.
It's necessary to use a camera version OV2640. If using a different camera, modification of the camera's pinout can be needed, or some camera settings may not work correctly. We recommend to use a camera module with a viewing angle of 120° or 160°.
These are currently known or tested camera modules:
| Camera chip | FOV | Resolution | Tested | Works | Description |
|---|---|---|---|---|---|
| OV2640 | 30° | 2MP | No | N/A | |
| OV2640 | 44° | 2MP | No | N/A | |
| OV2640 | 66° | 2MP | Yes | Yes | Recommended. Standard camera module |
| OV2640 | 120° | 2MP | Yes | Yes | Recommended |
| OV2640 | 160° | 2MP | Yes | Yes | Recommended |
| OV2640 | 200° | 2MP | No | N/A | |
| OV2640 | 222° | 2MP | No | N/A | |
| OV2640IR | 160° | 2MP | Yes | Yes | |
| OV8225N | 66° | 2MP | Yes | Yes | |
| OV3360 | 66° | 3MP | Yes | Yes | |
| OV5640-AF | 72° | 5MP | Yes | Yes | Overheating, slow photo loading |
There are currently 2 versions of the board, but only one version is possible programming via oficial CH340 programmer. The blue rectangle shows the differences between the HW versions.
The red arrow points to a pin that differs between these boards. In version 1, this pin is used for MCU RESET (GND/R). In version 2, this pin serves as ground (GND). Version 1 can be programmed via CH340, whereas version 2 cannot be programmed via CH340. For version 2, we tested programming via FT232RL or CP2102, and the programming process worked successfully.
If we want to program the MCU without the original programmer with CH340, or if we want to program the second version of the board, then we need to follow the following instructions. We will need a USB to UART converter, such as FT232, CP2102 or CH340. I have tested firmware uploading to the ESP32-cam with these converters. Uploading FW to the second version using CH340 did not work for me. Uploading FW using CH340 only worked for me for the first version of ESP32-cam board. For the next steps, I will use the FT232RL converter. We connect the ESP32-cam to the FT232 according to the following diagram, where we connect:
- VCC from FT232 to 5V on the ESP32-CAM. CAUTION! It is necessary to observe the maximum supply voltage of the ESP32-CAM, otherwise irreversible damage to the ESP32-CAM module may occur.
- GND from FT232 to GND on the ESP32-CAM
- TX from FT232 to U0R on the ESP32-CAM
- RX from FT232 to U0T on the ESP32-CAM
- IO0 from ESP32-CAM to GND on ESP32-CAM. By connecting the IO0 pin to GND, we switch the board to the mode in which it expects firmware uploading.
Next step is connect the FT232 converter to the PC and install the correct driver. Then we proceed with uploading the firmware to the ESP32-cam, which is described here. After successfully uploading the firmware to the ESP32-cam, we disconnect IO0 from GND, disconnect the FT232 converter from the ESP32-CAM, and connect the ESP32-CAM to the power supply.
The recommended version includes the MCU ESP32 (ESP32-S) with 520 KB of SRAM and external 4M PSRAM
Here is the partitions table:
| Name | Type | SubType | Offset | Size | Flags |
|---|---|---|---|---|---|
| nvs | data | nvs | 0x9000 | 0x5000 | |
| otadata | data | ota | 0xe000 | 0x2000 | |
| app0 | app | ota_0 | 0x10000 | 0x1E0000 | |
| app1 | app | ota_1 | 0x1F0000 | 0x1E0000 | |
| spiffs | data | spiffs | 0x3D0000 | 0x20000 | |
| coredump | data | coredump | 0x3F0000 | 0x10000 |
However, for uploading the firmware, it's important to use this configuration of addresses and files:
ZIP file with build binary files: esp32-cam.zip
- address 0x1000 - ESP32_PrusaConnectCam.ino.bootloader.bin
- address 0x8000 - ESP32_PrusaConnectCam.ino.partitions.bin
- address 0x10000 - ESP32_PrusaConnectCam.ino.bin
It is important to download the correct binary files! Each type of camera has its own ZIP archive with files for uploading the firmware.
You must use the console to upload the firmware on the MAC or Linux platform. First, ensure you have installed esptool for Python. You can find it on the manufacturer's website, ESPRESSIF, here.
And command for FLASH FW is here, where /dev/ttya0 is your serial interface for communication with the ESP32-cam board. This is the command for the first flash FW to MCU.
./esptool -p /dev/ttya0 -b 460800 --before default_reset --after hard_reset --chip esp32 write_flash --erase-all --flash_mode dio --flash_size 4MB --flash_freq 80m 0x1000 ESP32_PrusaConnectCam.ino.bootloader.bin 0x8000 ESP32_PrusaConnectCam.ino.partitions.bin 0x10000 ESP32_PrusaConnectCam.ino.bin
This command contains the parameter --erase-all, which erases the entire flash in the MCU. So, for just updating the firmware, it is necessary to remove the parameter --erase-all; otherwise, the MCU configuration will also be deleted. The basic command list can be found here
Here is the command for updating the firmware in the MCU without erasing the MCU configuration
./esptool -p /dev/ttya0 -b 460800 --before default_reset --after hard_reset --chip esp32 write_flash --flash_mode dio --flash_size 4MB --flash_freq 80m 0x1000 ESP32_PrusaConnectCam.ino.bootloader.bin 0x8000 ESP32_PrusaConnectCam.ino.partitions.bin 0x10000 ESP32_PrusaConnectCam.ino.bin
Launching the esptool application may be different in different operating systems
Driver for CH340 USB to UART convert for Windows is for example here . An older version of the driver is for example here. SW for FW flash (Flash Download Tools) is here
It's necessary to erase the FLASH using the ERASE button before the first firmware flash.
Board configuration in the Arduino IDE 2.3.2
- Tools -> Board -> ESP32 Arduino -> AI Thinker ESP32
- Tools -> Flash frequency -> 80MHz
- Tools -> Core Debug Level -> None
- Tools -> Erase all Flash Before Sketch Upload -> Disable (first flash, new board = enable. otherwise = disable)
- Tools -> Flash Mode -> DIO
- Tools -> Partition scheme -> Minimal SPIFFS (1.9MB APP with OTA/190KB SPIFFS)
When flashing the firmware to a new, empty ESP32-CAM device for the first time, it is necessary to use the 'Erase' function.
This can be found under Tools -> Erase all Flash Before Sketch Upload -> Enable.
After the initial firmware upload to the MCU, it's necessary to disable this option. If you do not disable this option, your camera configuration will continue to be erased from the flash memory after uploading new firmware from the Arduino IDE.
It is necessary to enable support for the correct board version in the file mcu_cfg.h after line 16.
To reset the settings to factory defaults, follow these instructions:
- Connect PIN IO12 to ground.
- Plug in the power supply.
- Wait for 10 seconds.
- After 10 seconds, the FLASH LED will start flashing.
- Disconnect PIN IO12 from ground (but don't disconnect the power supply).
- After disconnecting IO12 from ground, the FLASH LED will stop flashing, and the MCU will automatically reboot.
- Now the MCU is in the factory settings.
On the board, there is a status LED that provides a visual indicator of the module's current status through blinking at defined intervals.
Upon module activation, the LED illuminates. After processor initialization, the LED exhibits different blinking intervals based on the current mode of the module
- Service AP Mode only: The LED blinks every 400 ms, indicating the module's availability in service AP mode.
- Connecting to WiFi AP: While connecting to a WiFi Access Point, the LED blinks at intervals of 800 ms.
- Connected to WiFi Network: Upon successful connection to a WiFi network, the LED blinks at intervals of 4000 ms, signaling a stable connection.
- Problematic State: If an issue or error occurs, the LED accelerates its blinking to every 100 ms.
The approximate boot time of the device is 15-20 seconds.
Board description
Pinout
The board has a problem with the FLASH LED, as it lacks any current limitation for the LED. Consequently, frequent use of the FLASH LED can lead to malfunction, due to excessive current flow.
One simple solution is to connect an external LED via a relay, transistor, or MOSFET to the board, as shown in the next picture. Using a relay is not ideal, but it provides a simple solution.
Another solution is to use an LED COB or a USB LED lamp. I utilized a board from a simple USB LED lamp. The transistor has a current limitation of 500mA, and my USB lamp has a current consumption of approximately 180mA. The original LED has a current consumption of 60-80mA. After calculation, the total current consumption is approximately 260mA, which falls within the current limitation of the transistor. Therefore, it is possible to solder the negative wire from the COB LED or the USB LED lamp to the transistor. The positive wire needs to be soldered to +5V.
This is my USB LED lamp
The next step is to solder the negative wire from the LED lamp to the transistor collector, and the positive wire from the LED lamp to the +5V on the board.
The third option is to solder a resistor between the collector of the transistor and the PCB. I used a 10-ohm resistor in a 0603 package. This option is more complicated for users with limited soldering experience.
The standard ESP32-CAM board utilizes an internal antenna on the PCB. However, this antenna can sometimes cause issues with the quality of the WiFi signal, leading to slow photo uploads to PrusaConnect or connectivity problems. Fortunately, there is an option to connect an external antenna. This requires changing the resistor position, as shown in the picture below. Then, you can use a 2.4GHz Wi-Fi cable with a U.FL to RP-SMA connector and a standard 2.4GHz WiFi antenna
The device requires a 5V power supply, with a maximum current consumption of 2A. Power is supplied via a micro USB connector when using the original programmer.
Below you will find the wiring diagram for the DHT22 or DHT11 sensor.
| Camera board | DHT22/DHT11 |
|---|---|
| 3.3V | VCC |
| GND | GND |
| IO13 | Data |
- The flash LED may fail after some time due to the absence of a current-limiting resistor.
- The WiFi signal quality on this board may be weaker compared to other boards and may degrade over time.