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Hi there, in this instructable I will be showing you how I made an Automatic Pet Feeder using an old Digital Watch. Ive also embedded a video on how I made this feeder. This instructable will be entered into the PCB contest and as a favor I would appreciate it if you voted for this instructable down below. It would help us to create more awesome projects and share it with you on instructables :D

There are many methods to create a pet feeder using micro-controllers, but there are many people out there who find micro-controllers to be a hassle. So I decided to make a pet feeder using a basic timer (a digital watch with an alarm function), so that the people who do not prefer micro-controllers are not left out of the electronics hobby.

The necessary Eagle files will be attached below.

HOW this circuit works, will be described at the end of the instructable.

The tools you will need for this project are:

  1. Helping Hand for Soldering (Optional)
  2. Flux
  3. Solder
  4. Soldering Iron
  5. Screw driver
  6. Bent Nose Pliers
  7. Wire Stripper
  8. Hot Glue Gun

Additional tools you will require if you choose to make your PCB at home:

  1. Rough Sponge
  2. Laser Printer
  3. Iron or Laminator
  4. Containers
  5. Ferric Chloride
  6. PCB Drill Bit
  7. Drill or rotary tool

The components you will need are:

  1. Single Sided Copper Clad Laminated Board (for DIY PCB)
  2. Magazine paper (for DIY PCB)
  3. Thyristor 2p4m - 2
  4. LM7805 Voltage Regulator - 1
  5. LM317 Adjustable Regulator - 1
  6. PC817 Opto-coupler - 2
  7. Resistor 1k - 1
  8. Resistor 820ohms - 2
  9. Capacitor 47uf 50v - 1 (can be increased if needed)
  10. Female Headers
  11. Male Headers
  12. Servo (Tower Pro-Micro Servo SG90) - 1
  13. Digital Watch with Alarm function (which does not beep every hour) - 1
  14. Mini push button switch (tall) - 3
  15. Copper Dot Board - 1
  16. Thin Flexible Wires
  17. 10k Potentiometer - 1
  18. 9 Volt Battery Connector - 1
  19. Miniature Slide Switch - 1
  20. Potentiometer Knob - 1
  21. Micro Switch
  22. Nuts and Bolts
  23. Small Plastic Container (to store the food)
  24. 9V Battery

Step 1: Designing the PCB (using the Eagle Software)

Picture of Designing the PCB (using the Eagle Software)
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There are many softwares out there to choose from when you need to design a PCB. But the Autodesk Eagle software stood out to me since it is very professional and offers a huge component library which can still be expanded if you require, and provides a greater ability to customize the PCBs.

If you have never used Eagle before to make PCBs, download it for free right now.

I will attach the necessary Eagle files along with the pdf to print out the PCB.

Remember to print it out onto magazine paper using a laser printer. It did not work that well when I used glossy paper.

The setting should be set to "Actual Size" when printing, so that printout does not shrink or expand in size.