Teensy Typewriter



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.

Comments

Post a Comment

Popular posts from this blog

Defective Arduino USB Host Shield Boards

Image
UPDATE: The red wire is not needed. There are solder pads to the right of the reset button. Bridge the 5V pads to select 5V for VBUS PWR. In total, three blobs of solder are needed to make the shield work for 5V Arduinos. I received two new generic Arduino compatible USB host shields today. Both are defective. But they work after some troubleshooting. 1. After loading the USB_desc sketch, the debug message "OSC did not start." appears on the serial console. This means the USB host library cannot find the USB host hardware. I compared a defective board with a working board. One big difference is the 3.3V pads and 5V pads are not bridged on the defective board. This means the shield is not receiving power from the Uno! After bridging the pads, the board powers up. The error message "OSC did not start" does not appear. This means the USB host library found the USB host hardware. In the photo, the green boxes should contain one big solder blob. If there are...
Read more

How to use USB RFID readers on an Arduino Uno

Image
1. Plug the RFID reader into a Windows PC. Does it work without installing drivers? Open any editor such as NotePad. Read a card or key fob by passing the card or key fob on or near the reader. Do the characters appear on the screen as if typed at a keyboard? Look in Device Manager. The reader should be listed as a USB keyboard. If all the above are true, it should work with a USB host shield and Uno running the USB HID keyboard sketch. The same procedure applies to bar code readers. Do not expect all USB RFID and bar code readers to work like USB keyboards. Some devices such as RFID reader/writers require special USB drivers so are not usable with the USB host shield. The simple RFID readers shown above, read the RFID unique serial number. No other fields are returned. The readers cannot write to the RFID card. In the photo, starting at the top, are a 125KHz RFID reader, a 13.56 MHz RFID reader, Arduino Uno, and Circuits@Home USB host shield. Both readers work with the USB...
Read more

WeMos D1 R2 ESP8266 with USB Host Shield

Image
WiFi-enable a wide variety of USB devices using an ESP8266 and a USB host shield. For example, add a WiFi interface to a USB barcode reader or a USB RFID keyfob reader. The USB Host for Arduino driver  project has added support for ESP8266 so here are some of my experiments. For more details, see the demos on github.com. A modified USB Host Shield is plugged into a WeMos D1 R2 ESP8266 board. A USB host mini board fits on top of an Adafruit ESP8266 Feather. This configuration turns a $16 USB barcode scanner into a battery powered WiFi barcode scanner.
Read more