I want to connect my Arduino UNO to a serial device that once powered displays signature numbers. I want to then display those numbers on an LCD display. I have my 16x2 LCD wired correctly and it works fine even when I use the SerialDisplay example code from the library.

My questions are:

  1. Can I use a USB to TTL serial cable to connect the RX/TX pins of the serial device to the TX/RX pins of the arduino?
  2. The two numbers are more than 16 characters. How can I cut the numbers down and then display the two numbers on two seperate lines of the LCD display?

Let me know if I should provide further details.

  • You can only use a USB serial converter with something that is a USB host. Watch out for mismatched voltage standards when directly connecting logic serial lines. An easy way to split moderately consistent strings is either to count characters or look for a specific character you want to split on. Commented Oct 10, 2015 at 1:06

1 Answer 1

  1. If the device is serial and you want to connect it to the Arduino serial port, why would you use a usb-to-serial converter? For a serial to serial connection, you have to connect TX, RX and GND. This is the bare minimum for bidirectional communication, if your device is really read only, you can use just the TX and GND.

  2. it depends how you receive data from your "serial device" - btw, what is it? If the data comes as either ascii or individual characters, then it's easy: treat them as strings and display them separately. If the numbers arrive in binary format, you have to perform the conversion to string.

Questions like this should have attached at least a snippet, if not all, of code.

  • That's true! All I need is to connect TX of the device to the RX of the arduino and vice versa. I'm a newb. It's a handle of a medical device that I'm working with for a bionstrumentation school project. Also, I used a USB to TTL serial cable to see how the data is transmitted on the terminal on my computer and it looks like the data comes as individual characters. I was thinking to display them as strings too. I don't have much code yet apart from code that just gets input from the serial monitor. Thanks.
    – Tony
    Commented Oct 9, 2015 at 20:41

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