At the beginning of January I ordered an ESP8266-12 from BangGood, and pictured below is the board I received.
It’s branded as a DOIT.AM Devkit measuring 1.00″ x 1.90″. On my computer it connects as a USB device on COM4 at 9600 baud, N-8-1. Many tutorials have you connect via a terminal server program (I use putty) and issue an AT command, which should return OK. This board responds to the AT command with an error. It does connect however, so it’s already got some firmware loaded. If you type
print("Hello World") it returns Hello World.
It appears as a wireless unsecured network called DoitWiFi and wants password 12345678. It has IP address 192.168.1.1. It has a web server in place, and navigating to that IP address brings up a screen called “NodeMCU Doit Version GPIO DEMO” with two toggle switches, one labeled D0 and the other labeled D1. Turning D0 on illuminates a blue LED on the board, and turning it off extinguishes the LED. D1 doesn’t seem to do anything.
About a week later I placed an order with a Chinese company for two similar Dev boards for comparison; one uses the CH340 chip and the other a CP2102. When pressed for the difference between these chips the vendor stated “the CP2102 is more secure”. My research leads me to believe they’re similar. The CH340 is widespread, found on many Arduino clones.
These boards all have network names beginning with AI-THINKER_ and then terminating in a six-digit hexadecimal identifier.
Below is the CP2102 variant.
It also measures 1.00″ x 1.90″, but connects as a Silicon Labs CP210x USB to UART Bridge on COM5 at 115200 baud, N-8-1. When connected, issue AT, then Return followed by ctrl-j returns OK. Unlike the DOIT board, it returns an error if you try to issue the print command.
This one appears as a wireless unsecured network called AI-THINKER_0BEE98 with IP address 192.168.4.2. There is no web server in place, so navigating to that IP address brings up nothing.
Below is the CH340 variant.
It is a larger board measuring 1.20″ x 2.30″. Like the DOIT board, it connects on COM4, but wants 115200 baud, 8-1-N. Like the CP2102 version, it responds to the AT command as expected and does not understand the print command.
This one appears as a wireless unsecured network called AI-THINKER_D5CBFF with IP address 192.168.4.2. As above, there is no web server in place, so navigating to that IP address brings up nothing.
Of the three, I prefer the CP2102 version. I like the small form factor and I can purchase these in bulk quantities. Next up – flash the boards and put them to use!