ESP8266 D1 Mini Wi-Fi Module

The ESP8266 D1 Mini Wi-Fi Module is a powerful WiFi enabled processor in a compact package ideal for embedding into WiFi enabled projects.

Features:

Besides adding WiFi capability, the main claim to fame for the ESP8266 processor over the AVR processor of the standard Arduino is that it has a larger 4 MB of Flash memory and runs at clock speeds of 80 MHz and can sometimes optionally be overclocked to 160 MHz and therefore has a very fast processing speed.  These can be used as a stand-alone MCU in place of something like an Arduino or it can be used as a peripheral in conjunction with another MCU just to provide WiFi capability.

The module has a typical ‘Reset‘ button which resets the processor.

Digital and Analog I/O

All of the Digital I/O support PWM and interrupts except D0.  In addition they can be configured to have pull-up or pull-down resistors.  Though there are 11 digital I/O pins, 2 are typically reserved for use as the TX/RX lines if serial communications are used which leaves 9 digital I/O for other uses.

The blue on-board LED is connected to pin D4 (GPIO2) and can be accessed using the LED_BUILTIN constant.

Per spec, the digital I/O is limited to 3.3V, but the mfr has made statements that the digital pins are in fact 5V tolerant and there are many installations using the module directly connected to the logic lines of 5V MCUs.

The analog input is limited to a single 10-bit ADC input which is probably the most significant limitation for some sensor type applications. That limitation can always be overcome by using an external Analog Mux module like our 16-channel 74HC4067 or our ADS1115 4-channel 16-bit ADC module below if more analog I/O is desired.

The analog input does need to be limited to a maximum voltage of 3.2V or less on the A0 pin.  The module has a built-in 100K/220K resistor voltage divider on this pin that reduces the amplitude to a maximum of 1V at the ESP8266 processor which is the max that it can handle.

Powering the Module

The module can be powered via the USB port or by using an external 5V power supply connected to the 5V pin.

The 3.3V pin provides 3.3V output when powering the module from USB or 5V.  This output can be used to power an attached module such as a sensor.

It is also possible to power the module directly from 3.3V by using the 3.3V pin as an input, but in that case the USB cable or external 5V cannot be connected or there will be a conflict on the 3.3V power line.  Typically it is best to stick with powering the module from 5V.

Package Included:

1 X ESP8266 D1 Mini Wi-Fi Module

2 X Long Female Connector 8 Pins

2 X Short Female Connector 8 Pins

2 X Short Male Connector 8 Pins