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

Picture of Circuit
DangerousTim6 months ago
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!
Machine1 year ago

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.

ARPix (author)  Machine1 year ago

Thank you.

I used Target3001 and Cinema4D.

agis681 year ago


ARPix (author)  agis681 year ago

*thumb up* thank you

What about using a SD card to save the data you poke out ? Do you think it could be ease task ?

ARPix (author)  fabitencourt1 year ago

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.

You have my vote and I intend to make it. Good job.

wliu31 year ago
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.
ARPix (author)  wliu31 year ago

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

wliu31 year ago
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).
wliu3 wliu31 year ago
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.
ARPix (author)  wliu31 year ago

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

Very nice project and well done !


sdcharle1 year ago

This is fantastic. Got my vote.

thegrendel1 year ago

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

billbillt1 year ago


nataku1 year ago
I've been thinking about this but never really get there. Thanks for sharing.
Raphango1 year ago

Whoa! Great man!

zx lee1 year ago

Nice, love your great idea! Would try to make one for myself one day~

Awesome, well done :)

ARPix (author)  tronixstuff1 year ago

thank you

yair1 year ago

great project!
in what software did you use to render the PCB and parts?

ARPix (author)  yair1 year ago

The PCB and the schematic I created in target3001.
Then I imported this in Cinema4D.

unigamer1 year ago

Very nice, I like this idea! I couldn't find the LCD on ebay, does anyone have a link to buy it for a good price in the UK?

ARPix (author)  unigamer1 year ago

Thank you for your comment.

MMS Electronics Ltd. in Guiseley


You have to send an email to the company to request a price.

unigamer ARPix1 year ago
Thanks for the link. That's an interesting website. I've added your project to the long list of things I want to make but I can definitely think of times when something like this would have been useful. I'll probably have it as a self contained unit with a power source so it can mimic an FTDI cable.