Old TeleTypes and even typewriters had bells. Real bells. So that ASCII BEL character is supposed to make an honest to goodness ringing sound. While some modern terminals make a beep from the computer speakers, it isn’t the same. [Tenderlove] must agree, because the turned a Microchip USB to I2C bridge chip into a HID-controlled bell.
The only problem we see is that you have to have a patch to your terminal to ring the bell. We’d love to see some filter for TCP or serial that would catch BEL characters, but on the plus side, it is easy to ring the bell from any sort of application since it responds to normal HID commands.
If a bell doesn’t strike your fancy, you could use the same technique to easily add a digital output for anything. Of course, you could also use the MCP2221A as intended and put an I2C bus out there with a digital I/O expander or any number of other I2C chips.
Despite the video’s infomercial attitude, you can’t actually buy the bell. You’ll have to make it. It wouldn’t be very hard to duplicate with an Arduino or anything else you can connect to a PC as long as you modify the driving software accordingly.
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- arduino usb school bell