Node MCU who provides the LUA firmware also propose evaluation boards: http://nodemcu.com/index_en.html#fr_54747661d775ef1a3600009e
An Arduino + ESP-01 board, with an ATMega 644: http://rayshobby.net/cart/esptoy
ATMega 644 has two hardware serial ports
ESP8266-EVB is Evaluation board for ESP8266 with relay, button, UEXT, all GPIOs available on 0.1“ header https://www.olimex.com/Products/IoT/ESP8266-EVB/
The AI-Thinker board is an evaluation board with an onboard STC15L204EA microcontroller along with a relay, buttons and LEDs on all GPIOs, a relay, a buzzer, LDR, a socket for NRF240 modules, CH340 USB to Serial converter and DIP switches allowing different IO routing configurations to be setup. A small adapter board connects the normal ESP8266 modules to a pair of 2×4 headers. The board is widely available from a number of Chinese vendors, sometimes called a Coexistence Module. This is not the cheaper AI-Thinker “yellow board” (which should have its own entry on this page).
This is the left-most switch when the USB port is at top. Controls routing of the serial data lines.
| No. | Label | Function |
| 1 | DCRON | ON=Connect ESP TX line to MCU RX line. |
| 2 | DCTON | ON=Connect ESP RX line to MCU TX line. |
| 3 | ESPTON | ON=Connect ESP TX line to CH340. |
| 4 | MCUTON | ON=Connect MCU TX line to CH340. |
| 5 | ESPRON | ON=Connect ESP RX line to CH340. |
| 6 | MCU_R_ON | ON=Connect MCU RX line to CH340. |
So, to achieve the following standard configurations set the dip switch as follows:
| Configuration | 1 | 2 | 3 | 4 | 5 | 6 |
| MCU connected to CH340 | OFF | OFF | OFF | ON | OFF | ON |
| ESP8266 connected to CH340 | OFF | OFF | ON | OFF | ON | OFF |
| MCU connected to ESP8266 | ON | ON | OFF | OFF | OFF | OFF |
This is the right-most switch when the USB port is at top. Controls routing of some of the IO and signal lines.
| No. | Label | Function |
| 1 | GPIO14 | ON=AC relay controlled by ESP8266 GPIO14 |
| 2 | DLMCU | ON=AC relay controlled by MCU | | 3 | CHPDH | ON=Enable pull up on CHPD line of ESP8266. | |
| 4 | GPIO0L | ON=Pull ESP8266 GPIO0 down for flashing. | | 5 | GPIO15L | ON=Pull ESP8266 GPIO15 down (normal during boot) |
| 6 | GPIO2_L | ON=Pull ESP8266 GPIO2 down for ? |
Normally open, it can bridge the two AC terminal connections together. See above for control. High level closes the relay. Handles 3 amps at 35v DC or 3 amps at 250v AC.
Annoying. Apparently controlled only by MCU?
One is installed on the board, connected to the MCU. Holes for another wired to the ESP8266 ADC are in place but not populated with a sensor presumably because this version breaks out the ADC for independent use.
What is apparently an older version may be found in this thread.