Week 4: Timer Switch Use (Pros versus Cons)

One issue our group is facing is how the wiring is going to be setup. We need to figure out how to run the timer using a breadboard. Some problems we may face are actually getting the timer to run and programming it run at certain periods of times. The timer runs on 120v AC and 5 Amps, we need to figure out how this is going to be put into a circuit because  it uses a lot of power which is very dangerous.

Fig 1. Timer Switch (Closed)

Fig 2. Timer Switch (Open)

Week 4: The Frame (Pet Feeder Container)

Parts are finally starting to arrive in the mail! We have ordered several parts (some which have since decided against using) and expect to start assembly once they are all here.

The frame --which all pieces, parts, and covers will be assembled around arrived --earlier this week. It is essentially a cake tin that is 3 inches deep and 12 inches diameter. It is a lot larger than I imagined it would be. This is okay because I (speaking for myself only) was afraid that it would be too shallow.

[PIC]
But all is well :)

The tin encompasses 332.29 square inches of space. This is approximately tantamount to 23 cups.

Coming soon, there will be more information on the inner compartments which will divvy up these 23 cups. Ideas of how this intersections will be placed can be made when the rest of the mechanical pieces arrive in the mail.

The image in the post below (Fig.1) is an idea of what the compartment might look like, but it will change. For one, it will have to have a hole in the middle. Second, the slope closest to the center axis will likely change to accommodate a specific configuration of mechanical pieces, which have yet to be designed.

More on this next week.

Week 4: Segmented Food Tray

Now that the cake pan (feeder container) has arrived, the next step is to design the inner compartments that will be used to separate set food amounts. The most ideal method would include the use of the Creo Parametric 2.0 CAD program to design one tray that has 8 distinct compartments for pet food (See Fig 1.).

Each compartment would be of equal size and volume and walls between compartments would be sufficiently thick enough to prevent pet from accessing the next compartment's food supply.

Use of a CAD program and the 3-D printer ensures that the tray (that has specifically been designed for this model) will fit into the cake pan perfectly, leaving no room for food to escape or move around once pet feeder has been activated.

Fig 1. CAD Tray Design in 3-D

Specific details that relate to measurements needed for the CAD design process can be found on the Tutorial page

Week 3: Timer Switch (Timing Intervals of Cover Rotation)

We are going to use a timer switch instead of an Arduino. We found this to be more effective in the way our cat feeder is going to work. A timer switch is a timer that operates an electric switch controlled by the timing mechanism. The switch is connected to a circuit operating from a circuit connected to a breadboard. We will wire the switch so that the motor that will be connected to it will be given power for only certain amounts of time and throughout the day for as many days as the user would like.

Week 3: Arduino Use (Possible Switch to Digital)

An Arduino is a microcontroller that can run on a DC battery or a USB port in a computer. This system allows the user to input certain commands using the Arduino programming language. The commands allow several real life applications. The Arduino can do things like create a light show that controls several LEDs, or gauge water flow. However, initially, this group intended to use the Arduino to control the movement of a motor that would rotate the top of the pet feeder.

This is an Arduino Uno, which is an example of an Arduino the group was going to use

In the past lab session, the group was trying to figure out a ways to incorporate the Arudino in the project properly. The initial issue with the Arduino was trying to learn the language for the Arduino, which was very different from any of the programming that the group has done in the past. However, the group still tried to learn the coding by looking at certain samples. After trying to insert code that the group created and not having it work properly, some of the members found examples that would run a simple DC motor, but they did not work properly either. Even though the group did not receive any results, it still continued to research more on how to make the Arduino work. At the next meeting the group decided that using an Arduino in this situation would not be practical because if a person were to purchase this pet feeder, he or she would need to have a computer, and knowledge about programming. In addition, the group determined that there may be some unpredictability with the Arduino is something went wrong with the code. Finally, the group decided that a timer switch would be best for this project, which the group will write more about in the future.

Week 3: Gear Research & Calculations (Mechanical Approach)

Since we are now sure that gears will be an integral part of the project, it is time to decide how exactly.

The RPM of the motor which connects to the power system via potentiometer will have to be reduced using gear ratios. With 8 compartments and the maximum number of feedings per day being 4 (see first post) the pet feeder needs to rotate 45 degrees (360degrees/8compartments) every 6 hours (24hrs/4feedings).

So a hypothetical motor that rotates with a speed of 400RPM would need a lot of reducing. While it seems lofty, this is possible with 4 sprockets.

[PIC]

The first unit is the motor itself rotating at 400RPM
The second unit (1) rotates at 1RPM*
The third (2) rotates at 1 rotation per hour
The fourth (3) rotates at one rotation for every 6 hours in units of ___ degrees
The fifth unit (4) rotates at one rotation every 48 hours in units of 45 degrees

*The connection between unit one and unit 2 may be expanded.

Research on the Geneva gear:
The final unit can operate in a number of ways. It needs to rotate with 1/8th of it's teeth in short bursts every 6 hours. The Geneva gear is a mechanism that can help our system execute this kind of motion.
Here is an example of this dynamic connection type:

<---Unit 4 rotating 45 degrees every 6 hours




<---Unit 3 rotating 360 degrees every 6 hours



In simulation of this connection type, a dilemma was presented. For unit 3 to rotate the (approximately) 120 degrees needed to move unit 4 for one 45 degree step, 2 hours would need to pass. In other words, it would take 2 hours of motion for one compartment to open.

This is a problem. Other avenues will have to be explored.

Week 2: User Notification (Use of an LED)

One issue that the group was thinking about was how to notify the owner once the pet feeder has rotated a certain amount. The group reached the consensus that the best method of making the owner aware that the container is empty is by placing an LED light at the side of the pet feeder.



Initially, the group was considering to implement an alarm that would send out a low noise when the feeder would have rotated a full rotation. However, the group figured that an alarm would scare a cat off so the group decided to use an LED. The group believes that this would work when the top of the feeder fully rotates, it will set off a switch,which will in turn turn on the LED notifying the owner to replace the food. Then the owner will rotate the top of the feeder back around and turn the feeder back on. This seems to be the most effective, inexpensive and pet-friendly method of making the owner aware of the empty pet feeder.

Week 2: Circuitry (Digital Approach)

There are many different ways that the circuitry could be designed in order for the pet feeder to work. Based off of the knowledge that a DC motor would control the revolutions made by the pet feeder cover, the group debated the potential use of resistors within the circuit.

The group discussed two methods in particular. The first being a circuit that would make use of a 12V DC motor connected to different resistors. Each circuit path would have its own set resistance; which would correspond to a specific (user-input) feeding setting that allows for a set degree of rotation of the pet feeder cover. The difference in resistance would be due to an increased number of resistors (in series) for each circuit setting (see Fig 1.)

Fig 1. Pathways of Different Resistance

The second option would make use of a POTENTIOMETER; which is a small sized electronic component whose resistance can be adjusted manually (a manual variable resistor - see Fig 2.). It is used in various electronics e.g. volume knobs in music systems, fan regulators. Based on this concept the group was able to visualise how the user-dependent dial would help control the number of revolutions made by gears and ultimately the degree of rotation made by the feeder cover.

Fig 2. Standard Potentiometer

Week 2: Use of Gears (Mechanical Approach)

An essential component of out projects is creating gears that would revolve the top of the pet feed at certain times and snap the feeder into place at certain points.

The component we desire to create are similar to these. There will be several notches that will allow the top of the pet feeder to snap into place after certain times. In addition, we believe that the most effective way to create these gears are with 3-D printing. With a 3-D printer, the group could tailor the gears to the feeder and have them properly fit into the feeder. The program that the group intends to use is Creo Parametric to design the gears and this is also one of the programs that are compatible with a 3-D printer. 

There are going to have to be various gears, which the group still has yet to determine. In addition, creating these gears and find how exactly they will work will be a challenge, but the group hopes to have that issue sorted out but week 3 after extensive research has been done. 

Week 1: Preventing Overfeeding (Reduced Food Accessibility)

As mentioned, overfeeding needs to be avoided. The machine needs to make sure that the pet does not have access to more than one serving at a time. This can be done be convering the uneaten portion or by disposing of the uneaten portion --All before feeding again. This also helps to make sure that the pet has access only to fresh food.

• Covering:
  The ability to cover old potions before making a new portion available would logically suggest compartments. Compartments could be rotated between, clicked between, or opened and closed.
  Clicking between compartments would be the most ideal.
• Disposal:
  There are a few ways to take the uneaten potions of food out of reach
• Trap door to a waste bin below (would make using a scale nearly impossible)
  PIC
• Sweeping to a waste receptacle to the side
  PIC
• In order to dispose of the food in this way, a logical statement would be needed before the next feeding, outlined here:
• If not empty
     Dispose then refill
  Elseif empty
     Refill
  End
• The terms empty, not empty, full and refill would be of replaced by terms needed to use whichever actions (outlined above) chosen.

Week 1: Feeding Intervals

The only factor that determines the constraints of the proposed apparatus is the consumer's needs. It needed to be decided for whom exactly this apparatus would be designed for.
Would it be for the busy pet-owner that needed help with daily feedings? Or the frequent traveler who would need a week's worth of feedings and daily appropriation?
Furthermore, would this consumer be a cat-owner or a dog-owner? Maybe even a rodent or bird-owner?

So, how much to pets eat anyway?
Pet	Age/Size	Amount/meal	Meals/day
Kittens	2 months	3 Tbsp.	four
	3 months	3-5 Tbsp.	four
	4-5 months	0.25 Cups	four
	6-12 months	0.25 Cups	three
Cats	5-9 lbs.	.25-.5 Cups	two
	10-14 lbs.	.5-1 Cups	two
Puppies	Varies with breed. Can be read on back of food container
Dogs	3-20 lbs	.75-1.5 Cups	two
	21-50 lbs	2.3-3.25 Cups
	51-100 lbs	3.5-5 Cups
	100+ lbs	5-7.5 Cups
Rodents/Birds	All day, every day

Dials could potentially be used to customize feeding intervals. One dial could determine the amount of food per feeding (in ounces or cups) while another determines the time interval of feeding (in hours).

Programming to intake button responses is also an options.

Now, the machine would need to be able to tell how much food is in the bowl --in other words, when to stop feeding. This can be completed in a number of ways:

• Scale: Using weight measurements as input, the machine would know how much kibble would for example equal one ounce and would multiple that amount by the preference of the owner.  Heavy programming would be required.
• The owner would need to be able to rare the scale as necessary
• The owner may also be able to use a set and rare button to input desired weights, in lieu of a dial





Possible design of a infrared gates.
Cross-sectional view.
• Infrared: Using pairs of gates on either side of the bowl at certain marks (say 1/4cup, 1/2cup, 1cup & 2 cups), the interruption of a gate would mean that the mark has been met. This option would require light programming and could be completed in two ways:
• Programming based on consumer input via the dial would determine which gate was used.
• Each pair of gates could have its own circuit completed by the dial (optimal).
• Measured output: This option is purely mechanical and is ideal for this group's skill sets.
• This option has a multitude of execution possibilities. For example, a small scooper or fan (for a lack of a better word) could revolve allowing only a certain amount of kibble to pass per revolution. The kibble output (in ounces) per revolution could be measured and used as the factor which determined the number or revolutions needed to reach the consumer input (via dial).



Depiction of a a trap door

• This would be completed in a similar manner as option 2 of infrared option: mechanically, with different sized gears.
• Regardless of the complexity of this machine's user input, the output (the kibble) should trickle out rather than be dumped or fall.
• This is to keep the feeding area clear of stray kibble and to ensure that the amount put out is as close to the user input as possible

Another important feature would be a bell that would indicate to the owner that the feeder needed to be refilled.

Week 1: Brainstorming

It was decided that an automatic pet feeder would be made. Many idea were explored. It was important that the group improved upon products that were already on the market.

Some pet feeders drop the food from above, others poured it down a slot, and some just let gravity take over.

Crestuff Automatic Portion Conrol
$40 on Amazon

Replenish Pet Feeder
$16 on Pet Solutions

Looking at the currently available automatic pet-feeders, it was noticed that none of the products available on the market made provisions for waste. What would happen if the pet were to not finish his food in time for the next portion of kibbles? The pet would have access to way more than he needs daily.

That scenario should be avoided...

for obvious reasons.

The idea is the owner will not be there to supervise.

So, this feeder needs to 

1. Dole out precise amounts of food on a tailored interval
2. Dispose of uneaten food after a certain amount of time, before the next feeding

More on how that might be made possible, later.