Android tablet as serial terminal - works

[stevech]

I was surprised to find ....

Using my (old) Android tablet. A very nice if not fast Acer. Running older version of Andriod. Too old to surf the web, too slow with today's complex web pages.

I installed this free Android app https://play.google.com/store/apps/d...id.gousb&hl=en
Plugged in an FTDI USB to serial cable.
First try, it worked. No fighting, just worked. 115200 baud.

Then, I plugged in a Teensy 3 running a program I use a lot that I normally plug into my PC and use a serial terminal program (Bray's Terminal).
Amazing.. that Teensy 3 worked with the Android app. Two-way - I can type commands to the program running on the Teensy 3- which monitors the "Serial" USB for incoming ASCII text commands.
That Teensy 3 software is my 900MHz radio "sniffer" - it receives (from a 900MHz RFM69 radio connected to the Teensy), decodes each packet and displays kind of like wire shark (promiscuous mode).

I also connected the FTDI USB/Serial so the Android tablet can talk to a non-Teensy ARM M4 board with a 3.3V UART. Works too!
And the tablet's big battery runs the Teensy 3 as well.

So now I have another (portable) screen to use for my serial terminal. How easy does it get?

[pictographer]

Very good to know! Thanks!

[defragster]

So does my Android Phone with OTG cable. I tried the LITE/free/Ad version : "USB Serial Terminal Lite" and it worked.

Then I bought the $2.68 Ad free "USB Serial Terminal Pro" version

You can program a few MACRO response keys too that would be a one touch way to switch . And I installed it on my old phone from the same purchase.

I picked up a $10 device from Newegg that does OTG, takes Micro Usb power and will run a HDD or Teensy or another Usb: "rosewill rhbm-100-u2" This would provide Teensy power for longer runs without taking the power from the 'terminal' device - when you lose the charging port to the OTG device.

I mention this because I tried a few others apps for another device many failed - this one worked well first time with Teensy 3.1 and makes . The other free one I was using it 'Android USB Serial Monitor' - but it 'faulted' regularly on connecting, but worked.

[stevech]

I have that too. The author, at my request, added the ability to use fixed-width font. I use that to simplify printing out columns of data in debugging.

[Mat13]

I wanted to exchange data via serial between teensy and android phone with an OTG cable (no bluetooth involved) and I succeeded following your advice! Thanks @defragster
https://play.google.com/store/apps/d...n.freeusbtools

Here is the simple code I wrote on the Teensy LC
IDE setup to USB type: "Serial"

// works perfectly with Tensy LC
// and USB Serial Terminal Lite https://play.google.com/store/apps/details?id=com.oneman.freeusbtools
// plus an OTG cable between Teensy and Android phone

const int LEDpin = 13; // Teensy LED pin = 13
const int buttonPin = 4;
boolean statusButton = false;

void setup() {
  pinMode (buttonPin, INPUT_PULLUP); // in order to "press" the button: connect to ground
  pinMode (LEDpin, OUTPUT);
  Serial.begin(9600); // USB OTG serial com
}

void loop() {
  unsigned char inByte = 0;
  // listen to button and send to Android via OTG
  if ((digitalRead(buttonPin) == HIGH) && (statusButton == false))  {
    statusButton = true;
    Serial.write("PRESSED");
  }
  if ((digitalRead(buttonPin) == LOW) && (statusButton == true))  {
    statusButton = false;
    Serial.write("RELEASED");
  }
  // écoute OTG pour recevoir les paramètres
  if (Serial.available() > 0) {
    // read the incoming byte from OTG
    inByte = Serial.read();
    // visual check of incoming data from phone: light the in-built LED
    digitalWrite(LEDpin, HIGH);
    delay(100);
    digitalWrite(LEDpin, LOW);
  }
}

[defragster]

Very cool it still works! Not used in some time - just moved to a new phone will have to give it a function test.