Blinky Fish




About: Married to Domestic_Engineer (but I call her Meghan).

Assembly instructions for an add-on board for the Arduino.


It has some LED's and a button.  

It connects to digital pins 9-13 and ground.  My hope is that this will be useful to people that want to play with writing code for the Arduino, but don't want to build a little circuit every time they want to test something out.

I'm including all the files you would need to build your own.  I am also offering these for sale.  I figure this is the only real way to find out if this is useful to other people. 

I have only a few boards right now, but they are not quite right.  I have included a hack towards the end of this instructable.  

Here is a small web-store I've set-up.  The name is stupid, but easy to remember and spell.


Can buy kit here now.  (4/20/2013)


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Step 1: Parts

Here are the parts!

-PCB - 
-3 - LED's
-Push button
-Right angle header

Step 2: Tools

Tools - 

-Soldering iron
-Cutters (?)

-The soldering is pretty easy, so I never had to use the flux pen.

- To make anything happen, you will also need an Arduiono 2009 and a computer with the Arduino IDE.

- I like to work on a white peice of paper, it keeps me from loosing parts.  It is also a good if you are taking photos.

Step 3: Build - Resistors

Resistors R2,R3, and R4 are all 330ohm resistors. (orange, orange, brown).

R1 is 1K (brown, black, red).

[NOTE: the resistors shown in the picture are the wrong values - sorry about that, I was distracted by taking the pictures.]

Through hole components are pretty easy to solder.  

Here are the steps:
-Find the right resistor
-Put the leads in the holes
-Bend the leads out so the part doesn't fall out
-Flip the board over
-If the resistor falls out, but it back in
-Turn the soldering iron on and wait for it to warm up
-Put the soldering iron at the joint (between the lead and the silver circle)
-Wait a little bit
-Then touch the solder to the other side of the joint (away from the solder)
-Wait for the solder to melt and go all around the circle

-That is it!

If it doesn't work (the resistor falls right out or something), then you can just do it again.

After you do the soldering, you just need to clip the leads off.  Diagonal cutters are best, but you can use nail clippers or scissors, or whatever.

Step 4: Build - LED's

Now put on the LED's

LED's are one way, the short lead is negative.  This side of the LED is usually flat or notched or something like that.  On the PCB the flat side of the circle is for the negative lead.  

The soldering is the same.

Step 5: Build - Button

The botton only fits in one way (I think). 

You can just pop it in and solder.  The leads are sort of springy and bent, so that they stay in place nicely while you solder.  

Now isn't that clever!

Step 6: Build - Header

This is a right angle header.  Straight headers are more typical.  This is just like those, but bent at a 90deg angle.

Look at the picture below to see which way it goes.

It is a little tricky to hold the header in place while you solder, but you can do it!

If some of the hole are a little off center, then the header will stay in place nicely.  Of course, the person designing the board would have to think of this ahead of time....  so well, here we are.

Step 7: HACK - Cut a Trace

Well, if you've got one of the first few boards then you need to hack a little to get everything to line up correctly withe the Arduino.  ( I forgot about the resistor and LED attached to pin 13 on the Arduino board).

You can cut the trace between the button and R1 with an exacto knife.  

Step 8: Hack - Add a Wire

The next hack is to add a wire on the back of the board.

This goes from R1 to header pin 12.

Step 9: Attach to Arduino

Plug the Blinky fish into the Arduino.  The header pins are labeled to go with the Arduino pins.  Make sure that ground goes to ground and not to Ref.  It is an easy mistake (that got me confused for a little while).

Step 10: Test - With Arduino!

Here is a simple test program to see if everything is working.  

Once this is loaded on the Arduino all 3 LEDs should blink together.  If you hold down the button they well blink one at a time.  

If it doesn't work check some stuff.
-Is the Blinky Fish board plugged into the right pins on the Arduino?
-Do the soldered joints look okay?
-Are the resistors right?  (R2,3,4 are the same R1 is different)
-Maybe an LED is in backwards?  (make sure the flat side (or notch) on the LED is towards the tail end of the fish)

//****ARDUINO CODE *******

// blinkyFish_2


int Led1 = 11;
int Led2 = 10;
int Led3 = 9;
int Button = 12;
int PullUp = 13;

int ButtonState = 0;

void setup() {
pinMode(Led1, OUTPUT);
pinMode(Led2, OUTPUT);
pinMode(Led3, OUTPUT);
pinMode(Button, INPUT);
digitalWrite(PullUp, HIGH);

void loop() {

ButtonState = digitalRead(Button);

if (ButtonState == HIGH){
digitalWrite(Led1, 1);
delay (1000);
digitalWrite(Led1, 0);
digitalWrite(Led2, 1);
delay (1000);
digitalWrite(Led2, 0);
digitalWrite(Led3, 1);
digitalWrite(Led1, 0);
digitalWrite(Led2, 0);
digitalWrite(Led3, 0);
digitalWrite(Led1, 1);
digitalWrite(Led2, 1);
digitalWrite(Led3, 1);


Step 11: Board Layout

I laid out the board using Eagle.

Step 12: Schematic

Here is the schematic for the board.  

This is before the hack.  


Step 13: Design and Fabrication Files

Here are all the files.

The *.brd and *.sch files can be opened and edited in Eagle.

The zipped files are the files you would send to get the board made.  These are called "gerber files" (which means "the files you send to get the board made"). 

Gerber files are sort of like PDF's.  They are hard to edit, but can be read by read by most people and won't get messed up when tranfered from program to program. 

You can look at the gerbers in Eagle or with a gerber viewer such as VeiwMate (from Pentalogix (i think)).  Each file shows one layer of the board.  

These are:

-Top Overlay  (also called SilkScreen) - this is the white graphics
-Top Layer (also called Primary copper) - this these are the traces that you can sort of see on the top side of the board.
-Top Solder Mask - Circuit boards are acutally yellowish, they are painted green (or black or red or whatever) with a dielectric ink (insulator).  This keeps the copper traces insulated and keeps the solder from running all over when assembling the board.  This file shows every where that the green stuff does not cover.  That is, it shows the shiny silver parts.

-Bottom layer ( or Secondary copper) - shows the traces on the bottom of the board
-Bottom Solder Mask - Shows the exposed copper on the bottom of the board.

-There is also a Mechanical layer which is the outline of the board.  I suppose this is called "Mechanical" because it is cut with mechanical machine.  Unlike the rest of the layers, which are etched, screened or whatever.

-- So that is that.

Once I fix these boards (so they don't need the cut and extra wires), I'll post the new files and order some new boards.

Thanks for looking!


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    18 Discussions


    9 years ago on Introduction

    I just got my Blinky Fish kit, and am incredibly happy with it! I swapped out the three red LEDs for a red, green, and blue one. This is a great little project if you need some solder practice, or want to learn how to cut leads (for the time being ;P). Plus, it's hard to beat the price of it! I can't even remember the last time I had $2 shipping on anything that cost $6. Plus, PoopDirect's $4 ATmega 328 chips are the cheapest I've seen. All in all, great kit, and a great Instructable. Keep up the good work!

    1 reply

    Reply 9 years ago on Introduction

    "just got my Blinky Fish kit, and am incredibly happy with it!" Awesome! Thanks for the great comment. I am really glad you like it. Next up.... 'Hypnotic Cartoon Toad' -Marc


    6 years ago on Introduction

    Just received mine in the mail, and for an international shipping, $2 is the cheapest i've seen, definitely recommend to my friends

    When does you site open again for selling?Really want a few for in class

    Thanks - Right now I am sold out of everything, but I'm getting ready to order an updated version.    How many where you thinking about ?



    8 years ago on Introduction

    Since the kit appears to be no longer available would it be possible to make the board design available so we could make our own? Its a very cute and useful tool. Thanks.

    1 reply

    Reply 6 years ago on Introduction

    You asked me about this Blinky Fish project awhile ago -- I just made it into a kickstarter project here -


    9 years ago on Introduction

    I so want an Arduino, will have to check this out again when I get one.


    9 years ago on Step 9

    That seemed cool till now, but what´s the use of making something small and fun for kids if it has to be attached to an arduino board?


    9 years ago on Introduction

    This is excellent! Detailed, clear pictures, and the option of actually making it or letting you do the work :-) I only noticed one thing which needs fixing: On Step 3, you tells that the resistors are all "##K" :-)

    1 reply