ESP32_AA Battery Operated Breakout and Development Board

ESP32 Dev Board WiFi+Bluetooth Optimized for Operation on Alkaline Cells, CH9104 USB to Serial. Arduino Programmable.  Designed and Made in the USA

Here is the ESP32 development board with a connector for primary cells as a power source. Made in and ships from the USA. Other than the ESP32E module it has a CH9104 USB to Serial converter, A 3.3V LDO, Reset and Flash Switches and a multi color LED.

A version of the board with integrated LiPo charger and fuel gauge is available here.

The board includes circuitry to prevent inadvertent and possibly dangerously charging of non-rechargeable cells.  When an external battery is connected the current is limited to leakage currents.  When a battery is connected the blocking diode is bypassed with a low resistance FET to minimize the voltage drop between the battery and the voltage regulator.

A voltage divider is available to measure the battery voltage using the on-chip ADC.  The voltage divider is normally disconnected from the battery to prevent a small but steady current draw from the battery.  The voltage divider is connected to the battery with an electronic switch which automatically disconnects the resistors when the ESP32 enters deep sleep.

The board uses the latest ESP32-WROOM-32E module .

The Deep Sleep current is less than 10uA from the battery.

There are two tri-color LEDs on the board. One has the red and green LEDs hooked up to the CH9104 to signal transmit and receive activity and is powered from the USB connector. The other tri-color LED is connected to three IO pins on the ESP32 module.

The board supports auto-download from the Arduino environment and will automatically be set in download mode by the downloader. Once the download is complete the board will be reset, just like a normal Arduino board.  The download mode works safely and correctly with the battery connected.

All the required capacitors and pull-up resistors are fitted on the board. The board can be powered from an external power supply of up to 6V or the USB connector or both.

When the external power is present and power will be drawn from the external power supply or USB before the battery is discharged.

Boards purchased will receive the matching power cable.

The Cell connector is a JST2R commonly used on LiPo cells.

Unlike most other boards this one fits on a breadboard and has one row of pins accessible on each side of the board. Most of the pins of the ESP32 module are available on the external pins.

The module can be programmed directly from the Arduino environment without pushing any buttons. The upload speed is 921600 bps.

The module has been designed to be used in Sleep mode without excessive current draw.  I read 8uA when powering from the Vin and Gnd pins with the processor in deep sleep mode.

The overall dimensions and pinout is identical to the other ESP32 boards on this site.

The schematic is available here.

• 240 MHz dual core Tensilica LX6 microcontroller with 600 DMIPS
• Integrated 520 KB SRAM
• Integrated 802.11BGN HT40 Wi-Fi transceiver, baseband, stack and LWIP
• Integrated dual mode Bluetooth (classic and BLE)
• 4 MByte flash
• 3V to 6V operating voltage on the Vbat terminals if the battery is not used
• On-board PCB antenna
• On-board 32.768kHz Crystal
• 3 x UARTs, including hardware flow control
• 3 x SPI
• 2 x I2S
• 12 x ADC input channels
• 2 x DAC
• 2 x I2C
• PWM/timer input/output available on every GPIO pin
• SDIO master/slave 50 MHz