ESP8266 Notes

The Arduino ESC/POS printer library has been released. It is designed to work with USB receipt printers on the Teensy 3.6 USB host port. The Teensy 3.6 USB host printer driver is required. https://github.com/gdsports/USBPrinter_t36 https://github.com/gdsports/ESC_POS_Printer The ESC/POS printer library is based on the Adafruit Thermal printer library but is designed to work on USB receipt printers. ESC/POS refers to the commands to control the printer fonts, graphics mode, etc. The following is a useful reference. https://reference.epson-biz.com/modules/ref_escpos/index.php

My fork of the keymapper project is another result of experimenting with Teensy 3.6 USB host. The keyboard remapper supports alternate keyboard mappings including QWERTY, Dvorak and Colemak. Hot keys are defined to make it easy to switch among mappings. Both USB ports of the Teensy 3.6 are used. The host port is where the USB keyboard plus in. The device port is where the computer plugs in. The remapper reads key codes from the keyboard, swaps key codes if needed, then writes the key codes to the computer.

I have been experimenting with the Teensy 3.6 USB host library. The first result is the Teensy Typewriter project which connects a Teensy 3.6 with a USB keyboard and USB printer. Anything typed on the keyboard comes out on the printer. Next up (maybe) an ESC POS printer command library similar to the Adafruit Thermal Printer library. The commands are not quite the same and the Adafruit library includes lots of timing specific to the Adafruit thermal printer. After that the next project title will be "Teensy Typewriter ft. SMS". I have an Adafruit FONA somewhere. The idea is an SMS hardcopy terminal reminiscent of Telex/TWX machines.

If you need a wireless keyboard that works over long distances or through many walls, this might be the solution. The USB keyboard plugs into the sender board with an RFM69HCW radio. The receiver board with RFM69HCW radio plugs into the computer. All radio communications is encrypted using AES-128. Be sure to change the default key in the source code. https://github.com/gdsports/rfm69-usb-devices