My Summer Project

Actually I started in the spring renovating the unused upstairs bedroom.  It had wood paneling and white ceiling tiles.  A heavy oak sliding door which took three men to open reminded me of the saying, "The 80's just called, they want their room back."  I did a full gut job, new insulation, new floor, sheet rock, paint and molding.  Also, the electrical was two wire which I modernized on a new breaker.  No big deal right?  It's done every day.  The sliding door on the other hand I'm very proud that I was able to make it an automated sliding door.

Materials

1. Linear Actuator from OpenBuilds.  I bought the motor from them as well ~$120
2. Linear Motor Driver from Microcenter.  ~$10
3. Arduino board ~$20
4. Case and power supply.  I bought an adjustable voltage transformer that output 1.7Amps, current is VERY important on stepper motors.  ~$25
5. Some rubber gaskets and mild soundproofing.  ~$20.  This step is so critical because this thing can be loud!  It can rattle the structure if it's not insulated.  
6. Led's and arduino light sensors.  This is used to stop the door.  

Design Considerations

In doing research I noticed a lot of people did it with pneumatic actuators.  The problem was I needed a 30" stroke which is impossibly expensive if you can even find it.  $300 just for the actuator, then you need a pump and it has to stay pressurized.  The advantage is it's quicker.  This works better when you have two smaller sliding doors on either side and you can use both.  This door I could get it to open in minimum of 5 seconds.  After that the gears would slip and the door would sometimes get stuck.  I optimized the code to ramp up slow.  I have the stepper motor perform about 120% of what it needs to open or close the door and the sensor will stop it when it reaches the end.  If the door is completely open, meaning it's blocking the closet (pocket) side sensor it will close otherwise it will always open.  If it's half open and you press the button, it will open further.  

The door slides right into the closet space.  The mirror door leads into the closet.