ESM - ExternalSerialMonitor





Introduction: ESM - ExternalSerialMonitor

Sometimes I needed an external serial monitor like the Serial Monitor in the Arduino Editor, to see what is going on. So I made one.
The first picture shows an example how could be it designed.

For the ESM I used an Atmel Atmega328 (based on the Arduino-Board) because it have an internal SRAM with 2KBytes. It's necessary for the big data processing.
So you need more than 1KByte SRAM.

With the menu in the ESM you can do...
... setting the baud rate
... start and pause the reading

Step 1: Circuit

Step 2: Parts List

C1,C8,C10           100nF/50V
C2,C3                  22pF/50V
C4,C5,C6             1µF
C7,C9                  47µF/16V
D1,D2,D3,D4        LED-SMD OSRAM TOPLED, 9 mcd, green
Display1               EA_DOG-S102-6
IC1                       ATMEGA328(DIL28S)
IC3                       L7805 5V VOLTAGE CONVERTER
K1                        FEMALE CONNECTOR
Q1                        16MHz
R1,R2,R3,R4         100KOhm
R5,R6,R7,R8         100 Ohm
R9                        3,3KOhm
R10                      1KOhm
S2,S3,S4,S5         JTP-1230 BUTTON
S6                        SLIDE SWITCH
9V                        Battery

Step 3: Arduino Sketch

The main sketch.

Global variables are defined here.

The menu-functions.

The buttons are here defined.

The functions behind the menu.

Functions for the DOGS-102 display.
static void setChipSelectPin(PIN No. as const int)
static void writeByte(unsigned int)
static void Init()
static void begin()
static void drawPic(byte[8][102])
static void displayClear()
static void print(Text as char*)
static void print(Text as char*, Row as int)**
static void print(Text as char*, Col as int, Row as int)**
static void print(Number long, Col as int, Row as int)**

** Col = 0 to 102 pix, Row 0 - 7

Font definitions and functions.

The start image.

The SPI function.

Step 4: Example

The left homemade Arduino board contains the following code:

/ *
Serial Test Program
* /

void setup () {
    Serial.begin (9600);

void loop () {
   for (int a = 0; a <1000; a + +) {
     Serial.print ("int a =");
     Serial.println (a);
     delay (100);
This arduino sketch is what I created to test.
This program sends every 100 milliseconds a counter: "int a =" 0-1000.
The ESM (original Arduino board) is connected to the other Arduino via TX and RX (crossed).
Now you can press the play-button and it appears the transfer on the display.



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    28 Discussions

    Hi great project,would be nice to use a nokia 5110 lcd as its more easy to buy.thanks

    Hey there, great i'ble! Is it possible to connect a keyboard in some way to the monitor? That would totally eliminate the need for a computer!

    I love the high quality images of the printed circuit board (PCB) with components. Did you use the Eagle Schematic editor to do those or, if not which software is it?

    Voted because of the sheer quality of this instructable.

    1 reply

    Thank you for your vote.

    Yes, that's easy to integrate a datalogger. I think a atmega328 should be big enough for this. The Sketch for the ESM needs 7.832 Bytes and my datalogger Sketch needs 16.482 Bytes. I will try to cut down the size for the datalogger and i will create an another instructable with a compatible datalogger for the ESM.

    Oh yes so can this be modified to read from a computer serial port? I know there is a way to make a serial console for Linux.

    1 reply

    Yes, that's possible if you use as example a FTDI ft232rl Chip. Like on the Arduino Board.

    It would be more easier to make it you can use arduino (which is also based off atmel atmega328) so it is much easier for us AVR noobs to make one (though at the price of doubling the cost, I think it with that).

    2 replies

    Oh sorry I haven't read it through. Next time if you want to say arduino based then just say that. Using "atmel ATMega328 based" will only confuse people.

    Oh yes, that's right. Thank you for your information. I will change this.

    Very nice project and well done !


    Interesting project. I would be nice to use a cheap and readily available Nokia 5110 display, rather than the MMS-e DOG one.


    4 years ago

    I've been thinking about this but never really get there. Thanks for sharing.