What is it?

You need to see variables values. But Serial.print attach you to the terminal, is a slow blocking task and takes too much memooy. DiTell is limited to 4 digits, but is uses only one pin that can be shared with a led or a pushbutton. It takes 140 bytes of C code, 3ms transfer time. It works from 3V 15mA to 5V 40mA. So small you will easily find a place for one or many. On Arduino, the connector fits directly on pin 13, and you still can blink as usual.

Why did you make it?

Debugging real time software is more tricky than calling libraries. The value of some sensor is critical and need to be cheched continuously. Nice to see in which state is the program. Breakpoints, terminal with a nice presentation are incompatible with real time. Logic analyser and scope are great on the bench, not on the final product. DiTel is easy to connect, easy to program: adapt the setup to the pin you will use, add the Tell() function and thats done. Tell(intVar); or Tell ((byte1<<8)+ byte2); will display what you are intersted in.

What makes it special?

You find many 4-digit display that show hexadecimal. But you wrote your parameters in decimal, you are used to see the terminal showing in decimal the binary values of variables. Ditel do that hex to decimal conversion locally, when required: push the button and you can display values up to 9999. Plus other tricks.

Soon out of these small HP displays. We have the cheaper version with multi-source larger modules. See Ditell-B.