This is one pet goldfish that never needs feeding or his water changed. He's made of paper and sits on top of a servo which turns to change direction and oscillates to simulate swimming.
A Picaxe 08m microcontroller controls the servo but you could use any type that you are familiar with.
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Step 1: You Will Need These Items
To complete this project you will need,
- the goldfish template
- the gravel print
- micro servo
- 3-AA battery holder + batteries
- mini breadboard + hookup wire
- picaxe 08m microcontroller
- one 10k ohm resistor
- 100m of small diameter rod. aluminium, wood or plastic.
- plastic bowl. at least 150mm diameter and 75mm high.
You will also need,
- a knife to cut out the template
- double sided tape
- craft glue or pva
Step 2: STEP 1
Print the goldfish template on an A4 sheet of copy paper and cut out the parts with a sharp knife.
Step 3: Step 2
Once you have cut out all the parts you can start by gluing the fins together.
They are double sided so you need to match them up first.
Step 4: Step 4
Take the body of the goldfish and bend the triangle tabs at 90 degrees to the blank side of the paper.
Step 5: Step 5
Crease the paper at the point where the main body sides meet the center strip with the tabs and bend them as in the photo.
Start with one side and glue the tabs to the side of the body as you bend the center strip around to follow the curve.
It's best to glue them one at a time so you can make sure that the two edges fit together properly. It's a bit fiddly so take your time to get it right because a bad join ruins everything.
Once one side is done glue the other one down. Use a thin smear of glue on the tail halves and press them together, making sure that they line up.
Step 6: Step 6
Using the photos as a guide glue the fins to the body.
The top fin only fits in one place, just make sure it is in the center and straight.
Step 7: Step 7
Now we need to attach the support rod to the top of the servo arm. I trimmed the arms off mine and used the center hub but it's not necessary do do this. Use some superglue to fix the rod to the top of the hub. I used the tail shaft of an old toy helicopter but you can use anything that is straight and fits in the top of the hub.
Step 8: Step 8
Push the hub with the rod attached onto the servo. Stand the servo upright on the bench and use a spot of superglue to attach the goldfish to the top of the rod.
Make sure it is in the center and a little bit toward the front.
Step 9: Step 9
Now it's time to assemble the electronics.
If you have not used a Picaxe before I suggest you visit this site, www.picaxe.com. And you can buy the chips and prototype boards from www.microzed.com.au or www.sparkfun.com.
I have provided the code that I used so you can cut and paste into the picaxe programming editor.
I used a mini breadboard instead of a hard wired circuit. It's easier and allows you to add sensors or extra servos very quickly.
As you can see the layout couldn't get much simpler.
Step 10: Step 10
Once you have the circuit built and working you can use it as is or mount everything in a bowl as i did. I printed a gravel texture and cut it to fit the top of the bowl i used. Mine was 150mm diameter and 75mm high. You might have to resize the print in paint so you can fit it in the bowl or box you use.
I cut a small"x" in the center of the circle to allow the rod with the servo hub to pass through and onto the servo.
Step 11: Finished
Well that's basically it. I'm happy with the way mine turned out and if you make one i hope you enjoy it as well.
Feel free to make any changes to the circuit and the code. You could have a light or sound sensor to change his actions or even have multiple goldfish.
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