Hi, my name is Charles, I am a 15 years old guy who loves electronics. I own an Arduino Leonardo board, and I got the idea to interface it with a Dymo LetraTag XR label printer that I found for 20 bucks. So here is the main idea:
1-Connect the keypad with the Arduino,
2-Have software to make arduino issue keypresses to the LetraTag (for example: "H E L L O PRINT SHIFT+DELETE")
3-I'll have a little servo to push the blade to cut the paper, but that's not the deal now
Here's my problem: I don't know anything about interfacing matrix keyboard and programming a clock to scan presses and etc....
So, If anyone has done that with a similar keyboard, or anyone that knows the principe and could explain it to me, You are welcome!
CharlesDomingue:
Hi, my name is Charles, I am a 15 years old guy who loves electronics. I own an Arduino Leonardo board, and I got the idea to interface it with a Dymo LetraTag XR label printer that I found for 20 bucks. So here is the main idea:
1-Connect the keypad with the Arduino,
2-Have software to make arduino issue keypresses to the LetraTag (for example: "H E L L O PRINT SHIFT+DELETE")
3-I'll have a little servo to push the blade to cut the paper, but that's not the deal now
Here's my problem: I don't know anything about interfacing matrix keyboard and programming a clock to scan presses and etc....
So, If anyone has done that with a similar keyboard, or anyone that knows the principe and could explain it to me, You are welcome!
I think you can use optocouples or direct link if the printer use near 5V in these tracks for the keyboard. Maybe it is possible to hack the print head and motor and draw anything you want without depending on the fonts of the labeller?
ok, thanks for your reply, so I could note which keypress affect which pins, and build an array, buy 19 octocouplers and wire them to each pin and a com, when I activate two simultaneously, they get in contact and simulate the key. But how could I have 19 inputs on my leonardo? Charles
PS: I could also wire the thermal head and the stepper motor to the arduino like you said, which is a good idea, but I will be fine with only the default chip to handle the font and everything
CharlesDomingue:
can Analog inputs serve as outputs?
Yes, all the I/O pins can be used as normal (i.e. non-PMW) digital inputs and outputs on all Arduino boards. Sorry for not specifying that in my initial reply.
CharlesDomingue:
can Analog inputs serve as outputs?
Yes, or with some diodes and charlieplexing, or with a serial->parallel chip
I don't think I am advanced enough for that...
Far-seeker:
CharlesDomingue:
can Analog inputs serve as outputs?
Yes, all the I/O pins can be used as normal (i.e. non-PMW) digital inputs and outputs on all Arduino boards. Sorry for not specifying that in my initial reply.
That's nice to know, so I could have a 20th pin that controls the servo to cut the paper, and use for example pin 19 and 20 to control the sevo. That seems good, thanks for your help!
Now, I plan on having 19 N Channel mosfets, gate wired to my arduino, collector to a com and source to a pin on the keypad, so I would just have to trigger two outputs simultaneously to connect them, like a keypress.
My only concern is: is there a two-way flow capability on the drain-source when voltage is applied to gate (is it acting like a diode, the current can only go from d to s ? or it can go from s to d too?) ? I don't know that much on transistors, so a little help would be appreciated. Thanks!
