Arduino based serial/terminal monitor

I’m planning to make a very specific arduino based device to display serial output of another device (i.e. second arduino). When troubleshooting MCU circuits I find myself running between my soldering workbench and computer (that’s on another floor) to see serial output after I made a change in circuit . I have no room for laptop near my workbench… So I’m thinking of making a simple handheld ATmega based serial monitor device that will have small LCD screen (already ordered Nokia 5110 screen) and be portable (maybe even battery operated).
Should be simple enough, however if someone already did this I’d love to hear about it, so i don’t reinvent bicycle :slight_smile:
P.S. I did Google the subject but couldn’t find anything relevant…

You can find some serial lcds out there. Some of them are pure serial, in that it processes text normally, and handles newlines, carriage returns, etc. just like the serial monitor does. One is Liudr’s serial lcd backpack. He has several different modules, so go over to the store to see the options: Page Not Found

Of course, you could go really old school, and find a working VT-100 and make/buy a DB-9 cable, but if you don’t have space for a laptop, you probably don’t have space for a real serial monitor.

Many of the Digi-ole LCDs/OLEDs/TFTs support either a serial port, i2c, or spi, depending on how you set a jumper in the back. By default, it comes up in serial mode at 9600 baud. Note, you will need to run the digi-ole library, as you have to program it as a graphics lcd (the library gives you the standard print interface however). I have the 2.7" 128x64 LCD version, and have used it occasionally: If you already have a display, it looks like digi-ole has just the bare board that works with various displays:

You could of course switch to using i2c or spi, and then you have many more LCDs/OLEDs/TFTs to choose from.

Another solution I've used at times, is hook up a bluetooth HC-05 transceiver to the microprocessor, and then use apps on my Android cell phone as a serial monitor. If you are using some selected flavors of Arduino and have an Android phone with USB OTG support, you can use the ArduinoCommander app to mimic the serial port normally used by USB.

You can even run the IDE and download sketches with ArduinoDroid. I don’t have a tablet with USB OTG, and I tend to think running it on a normal phone would be painful with the screen real estate, so I haven’t tried it.

Great idea about Serial LCDs! I never worked with them, but if the can just read serial input directly it means I don't even need MCU attached. Thanks!

The digi-ole can read a straight serial line. I tried it out with my Teensy 3.0 and connected it to the first hardware serial port (Serial1, i.e pin 0, note in the Arduino Uno you would use standard Serial, I’m not sure about the other variants), and ran the example test program. I need to fashion a container to protect the LCD and the electronics.

I tend to use an i2c screen more often than the Digi-ole.

See my edited post about using bluetooth to hook up to an Android phone (Apple is also possible if you go to the more expensive Bluetooth 4.0 devices).

Just ordered Dig-Ole's LCD screen! Couldn't decide between plain LCD and OLED, but I think since OLDE uses more power LCD would be better for battery operated functionality :slight_smile:

The digi-ole can read a straight serial line.

Got my display today, awesome!
But I think you were wrong about it being able to read serial straight... It simply doesn't work, I think display expects few commands before it can start reading, so there's no way around using MCU in between.. Unless I'm not doing something right...

That's right, the MCU does have to add all of the extra commands to convert normal text to the display. You would have to add the DigiOleSerial library provided on the site, and modify it so it is serial only.

Sorry, if I was unclear. Liudr's serial lcd backpack that I mentioned does do what you want (it includes an AVR of some sort to drive the display).

No worries! I'll figure something out.
Great display tho. Looks gigantic compared to Nokia 5115 LCD. I just ordered another one (OLED this time) from them.