Project Logs

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• Servo amplification of facial features.

  Daren Schwenke • 10/30/2017 at 04:11 • 0 comments

  I was able to make the mask for this pretty soft and flexible, so for the short term I didn't need to implement amplification in the mouth and cheek area to get motion to transfer through.  It's still muted of course, but 'good enough' for Halloween.

  However, the eyebrow area could still use some help.

  So the plan is this.  I've said as much in comments, but time to make it a log.

  Use a conductive foam variable resistor or actual pressure sensor over the target movement area, with a matching servo moving the outer skin over the same area.  They are coupled in that the outer skin movement translates a bit to the inner.  The programming would simply aim to maintain the same resistance by moving the servo until that resistance is met.  Anything off of the target resistance would result in a correction of the outer skin in either direction to match.

  So you raise your eyebrow, which puts pressure on the sensor and decreases the resistance.  The servo reacts and pulls up on the outer eyebrow to raise the resistance back to what it was, relieving the pressure on the inner eyebrow sensor.  

  You lower your eyebrow and the resistance shoots up.  The servo reacts accordingly by letting go of the eyebrow and the resistance returns to the original.

  The baseline resistance reading is read on startup and movement in either direction is then tracked from there so it can be auto-calibrating.
  

  AKA.. Servo amplification of small facial movement.  Sounds good in theory..

  Problem is I have zero conductive foam left and I'm too cheap to spring for something I normally got for free back in the day when buying MOS/CMOS components.  :)  That and the conductive foam decays with age, and would be sensitive to moisture (aka, sweating would screw it up).
  

  So I'm currently figuring out what around the house I can use to make a suitable pressure sensitive capacitor instead and adapting my Teensy code for reading multiple channels of home-made capacitors.

  The real issue here is the target capacitance for an area the size of an eyebrow is about 5x lower than the designed capacitor size for that project so my Mylar dielectric won't cut it.  The pressure differential applied is also about 10x lower.  

  So I would need a dielectric at least 50x more effective to get a similar response, or I suppose I could just live with the noise of a 50x weaker signal...  Not yet.

  I have some pure white colorant for paint from back when I wanted to color urethane foam myself, otherwise known as titanium dioxide, in the garage.  Titanium dioxide as a dielectric is actually right in the range I would need... I have zero idea how or if it will be possible to make capacitors from paint colorant so... experimentation ensuing.

• Generations

  Daren Schwenke • 10/29/2017 at 23:32 • 0 comments

  Teen Groot and I went for a walk at the local Carnival today.

  Still no makeup or latex holding anything down for the little man so you'll just have to imagine his eyes actually blending in.  :)

  It was nice and cool out for Florida at 68 degrees and the wind was blowing.  Still, we spent two hours out in the sun and never broke a sweat.  That's good enough for a whole day at a Con.

• Pennywise gives Groot a hand.

  Daren Schwenke • 10/29/2017 at 06:18 • 0 comments

  We ran into Pennywise at Madeira beach today.

  Wow... what a perfectly creepy stare...

  Too bad I chopped off the red balloons.

• Extendo fingers

  Daren Schwenke • 10/29/2017 at 01:46 • 0 comments

  The hands were made from a children's size pair of mechanic's gloves, in black.

  Yeah, they were kind of hard to find, but the tools section at Lowes had them.

  The fingers were extended to match Groot's huge hands with a bit of polycarbonate cut from a fluorescent light guard tube.  This gave us a rigid structure, but not too rigid as to present a risk of injury.  

  The results are actually usable for grabbing things. 

  We also did not attach them to the shirt at inside of the wrist, so his hands can be taken out of the gloves for things like eating.

• Hiding the zipper.

  Daren Schwenke • 10/29/2017 at 01:11 • 0 comments

  To hide the zipper on the back, we attached vertical neoprene panels along one side of it, then made some more which crossed and fit into pockets.

• Painting it.

  Daren Schwenke • 10/29/2017 at 00:32 • 0 comments

  I experimented with painting and found that using just primer worked the best.  It gave a nice flat finish and put a load of color on the neoprene with a very small amount of paint.  Use too much paint and the neoprene will start to get stiff and the paint will just flake off.  Use just a misting and it sticks and stays.

  So first I did a light coat of white clean metal primer.  Using white first was important.  When I tried to get to the target color without it, I couldn't without a load of paint.  Spray from a good distance, about twice as far as normal.  It doesn't take much at all to get to about the 50% target coverage.

  Then a somewhat random 25% coverage coat of rusty metal primer (reddish brown).

  Then it was finished off by spraying it from the top down with some lime green paint, then some darker green fluorescent paint.

  While it is still a little wet, you can randomly rub some of the areas which would see wear in the real world (if Groot was in the real world) to darken those areas.

  No pictures of this, sorry.  I may do a follow up video later and add it here.

• Designing for Florida.

  Daren Schwenke • 10/29/2017 at 00:12 • 0 comments

  Neoprene is a good insulator.  This is a problem when the target environment is Florida.

  So about half of the suit actually has no neoprene on it, which exposes a good portion of his skin to the air.  

  You can see this pretty well when the suit is held up to the light.

  His inseam, the entire under arm area to the wrist, most of the shoulders, the top of the head, and a good portion of the chest are all exposed to the air for cooling.

  To keep this looking right and not to compromise the breathability of the spandex, you can't paint it.

  So after all the panels are attached and correct, you will need to tape off all the spandex areas before painting.

• Neoprene wood.

  Daren Schwenke • 10/28/2017 at 23:52 • 0 comments

  A short how-to on making the neoprene wood I used for this project.

  Basically brush with a wire brush in a single direction.  

  This tears the neoprene in such a way that it looks like wood grain or if you keep going, bark.

• Head and upper body.

  Daren Schwenke • 10/28/2017 at 03:12 • 0 comments

  Got to work carving the head and upper body.

  I started with polyethylene pipe insulation.  The poly insulation is about 1/8th the cost, but nothing sticks to it very well, it's very stiff, and it has a much larger open-cell structure.   The wire brush trick to make it look like wood also requires heating it afterwords to get it to look right.  I didn't like the results so I scrapped it all and started over with neoprene.

  Also ended up making panels from the softer neoprene pipe insulation for the head.

  Gluing it to the spandex gave it a stable base so it didn't immediately tear.  This allowed me to cut/sand it to shape nearly down to the fabric which gave the resulting mask really good flexibility.

  It seems I originally forgot to post the following video, so here it is.

• Modeling a 9 year old is hard.

  Daren Schwenke • 10/28/2017 at 01:04 • 0 comments

  Needed to build the costume on my son, or something the same size as my son.

  Since I didn't think he would stand still for 40 hours, we made a mannequin of him.

  Stuck some PVC pipes in and filled a pair of his too small PJ's with moisture cure urethane foam, otherwise known as 'Great Stuff'.

  To make something big like this actually cure, you need to spritz it with water as you are filling.  Normally moisture cure urethane foam will only cure up to a thickness of about an inch.  Soak the PJ's in water and hang them from a hanger.  Start from the bottom, and every inch of thickness of foam give it a good spray with water.

  As it was just about cured but still a little soft (about 30 minutes) I beat it back into shape.

  Then we tore/cut off the fabric and carved it back down to match his size.  

  Sorry about consuming your wig head mommy.
  

  Wear a chemical respirator when working with large amounts of urethane foam.  The stuff doesn't smell, but you can become sensitized to the isocyanates they release, which will make you feel like you have the flu the next time you come in contact with the stuff.  Trust me. 
  

  Some arms where added, and the entire thing was coated in acrylic (shipping) tape to prevent the contact cement from sticking if it soaked through.

  Then on went the black spandex full body suit I had sewn earlier to fit him with a zipper down the back.  I wanted it to fit exactly right so I made one from a workout shirt, some women's tights, and a spandex tube for the head from an earlier project.  

  If the spandex suit fits too tightly, when you remove it from the model it will contract and the neoprene will tear off the spandex.

  Sadly I didn't get any photos or video of my son creeping around the house in it like a ninja.

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