Gizmosmith

Cat Ear Code

This is the Arduino code for running the cat person ears. The circuit was simply three switches, one for each paw and one for the petting sensor, and a pair of servos. The code just checks each sensor and moves the corresponding ear.

#include <Servo.h>

//Servo pins
#define rightpaw 6
#define leftpaw 7
#define pet_sense 8

//Ear positions
#define r_up 95
#define r_down 160
#define l_up 180-r_up
#define l_down 180-r_down

Servo leftear;  // create servo object to control a servo
Servo rightear;

int pos = 0;    // variable to store the servo position

void setup()
{
  leftear.attach(9);  // attach the ear servos
  rightear.attach(10);

  pinMode(7, INPUT);

  leftear.write(l_up);
  rightear.write(r_up);
}


void loop()
{
  if(digitalRead(rightpaw) == HIGH)
  {
    rightear.write(r_down);
  }
  else
  {
    rightear.write(r_up);
  }

  if(digitalRead(leftpaw) == HIGH)
  {
    leftear.write(l_down);
  }
  else
  {
    leftear.write(l_up);
  }

  if(digitalRead(pet_sense) == HIGH)
  {
    leftear.write(l_down);
    rightear.write(r_down);
    delay(1500);
  }
}

Flaws with the original cat ears

My first version of the cat ears for people had these problems:

• The servos are not as powerful as I would like, so they don’t move the ears as far down as I wanted.
• The petting sensor on the headband between the ears was an afterthought, so instead of one cable leading from the headband to the controls, there are two.
• The paw cables snap to the gloves with normal clothing snaps. If you dance like a spaz, they will get unsnapped.
• The palm material of the gloves is insufficiently stretchy. This puts a bunch of load on the seams and, given time or big beefy hands, might cause the seams to fail.
• The cable between the controller board and the gloves and hands has a non-locking, non-polarized connector in the middle of it. It is possible for this to get unplugged and then put back together backwards.
• The cables are all absurdly long. It would fit me better if I was nine feet tall.
• I’m not terribly pleased with the construction of the ears, particularly where the ear lining meets the headband.

I’ll be posting a bunch of links to the techniques used in making the ears and the code soon. It won’t be a full write-up of the process, but it will be enough pointers for someone who wants their own set of ears to do it fairly quickly.

If you can’t sew, solder, and operate simple hand tools, you may want to get a friend to help, but then you can make two sets, and bat your ears at each other.

Why I don't sell things

I have this problem, which may be common, and may not be a problem, where I don’t consider the things that I like doing as ways to make money. I do stuff like building random electronic devices because I enjoy the process of doing it. On the rare occasions that I’ve done it for money, I’ve found that the work stopped being fun and started being work. As a result, when someone approaches me about my hobbies with an eye towards monetizing them, I tend to react like someone told me I could sell my (hypothetical) pet cat for sausage. I could, and I might even make money off it, but it wouldn’t be fun and it misses the point.

That’s part of the reason that I don’t see a problem with making something and then giving it away (to a good home, that is. I don’t build things to be thrown away). Giving things away is usually bad business. It ensures negative margins and financial loss. I may lose money on the transaction, but life isn’t transactions, it’s experiences. I had the experience of taking a bunch of stuff that did nothing, building a functioning thing, debugging it, and learning from it. Once it’s built, it’s just an object, but while it’s being built, it’s a process. If a business is efficient, there is as little process as possible to make as many objects as possible. If a hobby is fun, there’s tons of process and the object is secondary, if it exists at all. Consider sports. You can go play frisbee with nothing but sensible clothes and a frisbee. At the end of the game, you haven’t created anything that can be sold, but you went through a process that was rewarding in and of itself.

It may be that entrepreneurs view their businesses the same way, with the functioning of the business being the process and the end product being the object. From that point of view, a streamlined management structure may have the same beauty and utility as a well-designed and smoothly implemented software framework or a well-designed sensor circuit.

However, understanding someone’s point of view is not the same thing as assuming it. As a result, I won’t be going into the cat sausage business any time soon.

While I was at the Mini Maker Faire, a bunch of people asked if they could buy various things that I had. I hadn’t applied for a permit to sell things, so I didn’t sell anything. I had two reasons for not selling things at the faire in general, and one reason for not selling my animatronic cat ears in specific.

The first reason to not sell at the faire is simple. I didn’t have anything to sell. Everything I wanted to take to the faire is stuff that I was proud of making and planned to keep.

The second reason is complex. I don’t really think of the Maker Faire as a place to buy and sell things, so much as a place to meet people and learn about things. Commerce is certainly present, but in terms of how I approach the event, it’s a lot closer to Firefly than the MIT Flea. Selling things is not the interaction that I want to engage in with people. I’d rather learn about what they are working on and teach them about what I have worked on.

The reason I wouldn’t sell the cat ears is that they are a prototype. I found several bugs in the initial shakedown that I haven’t fixed. I could fix them if I was going to make a production model to sell, but i probably won’t do that, for the reasons detailed above.

However, now I have a list of things to watch out for in the design, and the existing design. That’s enough to publish here and let other people make their own versions. Teaching beats selling any day of the week.

Me Showing off at Maker Faire RI