Teensy USB Host/Slave?

Hi,

I am dreaming to make a device that will allow a user to plug a keyboard into the USB end and type things, and the device will write what the user types into a file.

This device is essentially a self-powered keylogger, like this: https://www.keelog.com/usb_hardware_keylogger.html

But.. it is for creative writing, designed to NOT be plugged into a computer while the user is writing. It's self-powered.

I am the creator of ilys.com and wish to start making hardware versions of the concept.

Then after typing, when the user plugs the device into a computer, the computer reads the device as another drive, as it usually does with other SD cards, etc. The user will be able to copy the text file to their computer.

The device would be self powered, and provide the power the keyboard will need for it's operation.

I have never used arduino before and don't know much about it yet, though I am pretty good with software.

Can you please tell me if, the dream of this device is possible with Teensy and what I would need to create it?

Or should I look into other directions?


Thank you so much for your guidance and help,
Mike Gurevich

The Teensy's don't yet support USB Host Mode out of the box. The Teensy's are designed to be plugged in to a host.

Theoretically the hardware is capable and if you search on this forum, you'll find some posts from a fellow named Andrew who is working on the software. Here's the most recent thing I've found on USB Host Mode:
https://forum.pjrc.com/threads/28173-Teensy-3-x-NATIVE-USB-HOST-PREVIEW-AVAILABLE?p=87473#post87473

There's also a hardware add on that does support USB Host Mode. Haven't tried it, but it's been around long enough that it probably works. http://www.pjrc.com/teensy/td_libs_USBHostShield.html

If you were willing to use a PS/2 keyboard, interfacing to the Teensy would be simpler, but I understand that might not fit your concept. https://www.pjrc.com/teensy/td_libs_PS2Keyboard.html

The Teensy 3.2s probably have enough memory for the amount of typing your users would do before plugging in. The Teensy LCs probably don't. You can add memory, but that's additional hardware and complexity. Here's the link for basic EEPROM access. https://www.pjrc.com/teensy/td_libs_EEPROM.html

I'll leave it to you to find the eeprom specs for the Teensy 3.2.

There's also an amazingly cheap small touch screen available for the Teensy's. https://www.pjrc.com/store/display_ili9341_touch.html

Hi! Thank you very much for your reply

>> The Teensy's don't yet support USB Host Mode out of the box. The Teensy's are designed to be plugged in to a host.

>> Theoretically the hardware is capable and if you search on this forum, you'll find some posts from a fellow named Andrew who is working on the software.

>> There's also a hardware add on that does support USB Host Mode. Haven't tried it, but it's been around long enough that it probably works.

Yes, a hardware add-on would be interesting to learn about. Can you please point me to where it is?

>> If you were willing to use a PS/2 keyboard, interfacing to the Teensy would be simpler, but I understand that might not fit your concept.

Yes, I would surely use a PS/2 keyboard, especially for the first version, proof of concept.

>> The Teensy 3.2s probably have enough memory for the amount of typing your users would do before plugging in. The Teensy LCs probably don't. You can add memory, but that's additional hardware and complexity.

Not having to use an SD card would be a wonderful thing! This is all text, so I imagine it wouldn't be a heavy load for memory.

>> There's also an amazingly cheap small touch screen available for the Teensy's.

Wow!

>> If any of this is of interest, I or someone else can find you links.

Yes please, all of it is interesting!

Thank you very much,
Mike