Tuesday, July 24, 2012

Prototype in the making

Update #1 :

As I planned last week, the prototype for the mechanical pet feeder is made using Styrofoam.

Due to lacking of few tools needed, I had to make my own foam cutter. Without any nickel wire in sight, I had to use a resistor (and burn it). The Styrofoam wheel were cut using method like this.

The wheel are made from foam and thick paper. I made a small hole in the middle of the foam and squeeze the servo's 'hand' inside. The specification of the Servo I used is available, here. The styrofoam parts are held up by hot glue.

Below is the video of the prototype (I called it the v0.1). It is controlled by an testing application I made (Visual Studio and Arduino). Pardon the video quality. In the video is the best run so far, the machine often get stuck.

I have done an experiment on the Pet Feeder (V0.1), with 100 tries and below is the results :
failure rate : 60 out of hundred = 60%
success rate : 40 out of hundred = 40%
Details on the experiment is available, here (dropbox), or here (google doc). In this experiment real cat food (pellet/kibbles form) were used.

Problem / findings :
  1. Sometimes the servo/wheel get stuck (As shown in the video, at 1:30). This is possibly due the restriction near the wheel and the slope.
  2. Sometimes food get into places that I shouldn't be. In between the wheel and the side and bottom part of the feeder, makes the wheel stuck.
  3. The chute slope is not steep enough, food get stuck on the chute.
  4. The slope on top (the storage area) is also not steep enough.
Planned solution :
  1. Reposition the plastic flap (used for restricting the pet food to flow out)
  2. Add more space between the wheel and feeder side.
  3. make a steeper food chute
  4. make slope steeper.
Problem 1 and 2 is more serious and will be given higher priority. Based on this, I will execute the planned solution.

Saturday, July 21, 2012

Week #7

For better understanding the explanation for the project are divided to two parts, Part 1 (hardware) and Part 2 (application).

Part 1 : Hardware
In order everyone could grasp what actually project238 (mechanical pet feeder) is, I would like to share few examples of Arduino projects by others.
  1. Twitter controlled dog feeder. (inspired the project)
  2. Plant monitoring system
  3. Doorbell alert system
  4. Real tracking and shooting portal turret
  5. Water monitoring system.
But my personal favourite is the, The secret knock detecting lock.

Links : grathio.com | instructables.com

My design for the mechanical pet feeder is based on the cereal/food dispenser, which I had seen before during a breakfast buffet. It uses a rotary movement to moves the food in the container down to the bowl.

In my design (as the picture below) storage is where the pet food stored. The pet food will drawn down to the rotary wheel by gravity. The perimeter of the wheel are closed except marked by the dotted line. The rotary wheel will turn clockwise and pour the food down the chute and down to the food bowl. It will then get to the original position to start the cycle again.

Apparently someone had a very similar design which he uses it for his dog food dispenser. I will make his design as a guide and reference for this project.

The servo I have ordered finally in my possession, I have tried to play around with it. The servo is a mini servo, the amount of torque(around 1.6Kg) would be enough for the prototype design. Prototype will be made out of Styrofoam, pictures will be up soon. Suggestions are most welcome.

Part 2 : Application
For the application controlling the mechanical pet feeder, the functions are listed as below.
  • Application able to signal an instant feed command.
  • Application able to set time interval between each automated feed.
  • Application able to disable the automated feed.

After taking consideration on the findings of my research, the application will be develop in C# using Microsoft Visual Studio 2010.

Any suggestions are very welcome.

Monday, July 16, 2012

Week #5 and Week #6

In this 2 weeks I have prepared and revised on the draft report for chapter 1 and chapter 2. In between of that I tried out C# programming and serial communication with Arduino Uno. Here.

Next for the report is the explanation of the phases in developing the mechanical pet feeder with Arduino Uno. What I have done and what I plan for next trimester. A very important step to keep the project on track.

For the design, I already have one planned. I may use AutoCAD or Blender to draw the machine design for more proper documentation, but first I have to learn to use them. I might just use my photoshop knowledge if its sufficient enough to portray the design.

The fun stuff soon to come :)