This derivative of the IKEA FAMNIG HJÄRTA red heart cushion was Inspired by Adafruit's own robot Adabot, star of Circuit Playground. Of course, we also have the Instructables Robot Robo-Heart Plushie too.
This project was kept simple as to really inspire those to get making and to encourage the exploration of electronics. I guess you can classify this into soft circuits but for more advanced users, it makes a great beginner project for integrating a microprocessor like an Arduino found in the Adafruit Flora, Gemma or Trinket into this "wearable"(pin it on your sleeve?) No 3D printer, laser cutter, or oscilliscope required...not yet.
Make stuff light up and blink. It's cool.
CAUTION: Learn to sew. Learn to solder. Learn to do electronics. Do it safe.
Step 1: Spare Parts and Stuff...
For the roboheart, you will need:
felt or softer fleece material
(light blue, medium blue, white)
fiberfill for stuffing
some scrap corrugated cardboard
paper for papier mache
blue paracord for trim
hot glue gun to attach paracord
LEDs (2 white LEDs, 4 red LEDs)
battery holder or terminal (I used a 9 volt battery)
appropriate resistors for your circuit
soldering iron and electronics tools like wirecutters and pliers
sewing machine, you could do it all by hand for a more rustic look
Step 2: I Felt a Beat...
I got from the discount fabric store some sheets of felt that were the right color for Adabot.
You need to cut out a heart shape for the main body of your plushie.
I just eyed the right proportions and folded it in half to cut out a symmetrical shape.
Cut out two pieces, one for the front and one for the back.
The top portion that was cut from the golden mean will be used to make the arms.
Step 3: Get a Grip...
Next we are going to make the robot claws. It should be a little bit smaller than your fabric heart.
Sketch out a heart shape on the cardboard.
The claw is about an inch wide and thick so draw a concentric heart inside the outline.
Cut this out for your template.
Use the template to cut out several pieces of corrugated cardboard to stack up and laminate by gluing together.
I used about four layers to get a nice thickness of the claw.
Roll a small piece of cardboard or just fold it into a rough tube to make the tenon to attach to your fabric arms.
You can just poke that in place after you get all the laminations set. Apply glue before you push it into position.
I did a quick papier mache to cover everything. Just tear up pieces of scrap paper to use and apply glue directly. Burnish the rough surfaces with the barrel of the marker.
When dry, you will have a solid piece to work with and use.
Step 4: A Set of Chompers...
Ideally thin felt needs an interfacing or something with more substantial heft to it so the fabric will run through the sewing machine better and not pucker from the sewing. I cut another heart shape to bulk up the felt.
I cut a piece, doubled over, that is in the shape of the mouth.
The extra layers will help in the diffusion of light from the LEDs to be placed inside.
After the mouth shape is double stiched around, you can sew in definition lines for the teeth.
On the opposite side, cut out the areas inside the teeth.
The lines sewn down will retain the blue layer of felt to give you a neat frame for each tooth.
Now is a good time to sew on the lightning bolt soulpatch. You could also do this later if you just want to glue it on.
Sew the tubes for the arms.
Turn inside out to give a nice finished seam.
I split the ends open a bit so I can attach it easier to the front and back pieces.
Tack one end of the opened tube to the sides where the arms go.
Step 5: Back It Up...
I've got some electronics to pack into the body so to make it easier, I made a split overlapping back piece.
I hemmed the bottom of the top portion and created another overlapping filler piece to cover.
You are now ready to create your inside out sandwich.
Have the arms placed inside.
Position the back layer on.
Sew all around to form your heart shape.
Where the arm tubes are, sew to keep an opening so you can feed the wires and stuff it later.
Turn the assembly inside out by first reaching through your split opening.
Adjust the arm length by folding back the excess fabric into the tube. It will help hold in the claws with a friction fit.
Step 6: Shocking Developments...
I wanted the mouth and claws to light up.
I wanted the lights to be activated when the claws touch together.
To do this, one circuit will be for the lights in the claws.
The other circuit will be for the lights in the mouth.
I had a 9 volt battery connector so I decided to use a 9 volt battery as my power source.
When working with LEDs, you should always use in conjunction with a resistor so that the LED does not burn out from a current spike.
There are "LED calculators" which can design your circuit for you.
I used one that designed for me three sets of 2 LEDs in series with a resistor all wired in parallel to my battery.
And that is where the fun begins...
The claws would be 2 red LEDs.
The mouth would be a set of white LEDs and a set of red LEDs. I just poked holes in a piece of laminated cardboard to hold the LEDs in place and wired behind it. You can protoboard it if you have it available.
I was going to use some exposed wire traces as contact wipe switches on the ends of the claws to act as switches for the lights. You could get fancy and do sewn conductive thread pads, conductive fabric pads, lengths of solder wick, metal hardware like washers and even tinfoil pads.
I did not really have the exact data specs of my LEDs so I input some near values into the calculator.
When I wired everything up, one set of LEDs would work for a while and then not work.
Good practice is to test as you go. Nothing worse than having to take apart several steps of construction to fix or trace a fault.
I thought one LED was burning out or there was faulty wiring. When I swap connected my switch wires, I did get the mouth LEDs and one claw LED to light up. Really odd. I did use my ebay 1000 for 10 bucks components so everything was suspect. I may have broke a wire somewhere I flexed it. I used the strands out of CAT5e cable for my wiring.
To make a long story short. I ended up adding a second battery to create an entirely separate circuit for the red LEDs for the claws. I do not know if the white LEDs caused some load imbalance and drew the current away from the third set of LEDs since I had used the same resistor value throughout and did not account for the higher draw of the white LEDs. Oh well, my brute force solution for the problem, maybe I should ask an engineer.
Step 7: Add Fluff...
Route all the wires through the claws and the arms.
Cover the claws with fabric. I should have used the toxic spray adhesive for the felt. Gluing felt to felt is a chore because it soaks up white glue like a sponge and will take forever to set up and dry. I also seemed to have grabbed an old bottle of white glue., you know, from when they have the 5 cents sale at the office supply store and you hoard up for kindergarten and still not use up all that stuff until the kid is in high school...composition books anybody?
Tuck in all the wiring.
Stuff with fiberfill.
It's so fluffy.
Don't overstuff the arms like Popeye. If you do, they will be hard to flex and bend later. You can now add the final trim detail by winding around the arms with blue paracord and tacking with hot glue on the back.
Happy Valentine's Day!
Make a roboheart to spread the geeky love.