Hi all, total noob here, I never did too much with arduino but I really want to do something for the poor cats living on the streets.
So I found and 3d printed a nice feeder with auger for dispensing food.
I need your help with figuring out what would be the best way to power it, and with what.
I do have Nano, 28byj stepper motor with blue board 2003.
If that's not enough, I can get something else. I did read somewhere that an RTC module would be helpful.
As I would want for the feeder to dispense food twice a day, and preferably it would run for at least a week or so on some kind of batteries.
Have you tested you setup, yet? How are you powering the system to test it in your shop? How will you keep the poor dogs from chasing your cats away and eating their food?
I did test it, I have the nano on breadboard, connected with 2003 and that to 28byj, I uploaded some simple code to check if everything is ok. Which it seems ok, I powered it through usb.
By the way, the stepper is not moving in the CCW direction only CW (yes I did checked it in the code)
There are no dogs in the village, only cats.
Unless you need the auger to fill the reservoir, you only need to turn one way. So, now get a real-time clock module and learn how to program it. Add that to your code and you are all set.
You should post pictures of how this food-dispenser looks like.
If you can afford to use a car-battery - a car-battery will have enough energy for two weeks of operation maybe even more.
If you want to keep the battery as small as possible the mechanical design of the food-dispenser must be in a way that gravity is used to do most of the work for dispensing.
One idea - which will deviate very much from your current design would be to have 28 tiltable containers filled with food.
each feeding-time a small motor will loosing a holding mechanism so gravity will tilt one container and the food pours out.
Pulling out a small pin will take much less energy than pulling up the whole food.
Or the containers are on a rotating disc and in one position the containers will tilt through gravity
For estimating how much power the motor needs you should post a picture of the food-dispenser
As a side-note:
Investing money into sterilisation of the straycats will reduce the number of straycats over time.
My girlfriend had one of these. She bought it when she couldn't get a pet-sitter or boarding when we were going on a trip.
It turned-out to be good investment! But, programming wasn't "user friendly". I don't know what kind of motor it had, but I think the feeder mechanism was something like a rubber paddle wheel. (Something special and custom made.) It used 3 D-batteries and they lasted a long time... Several months or more..
The advantage of a gear motor is that DC motors generally have higher torque and the gearing-down increases torque (at the expense of speed). You can't accurately control the amount of rotation, but when it's slowed-down it's easy to control the time, or at slow speeds it's not too hard to add sensors to count rotations, etc.
You may not need a real time clock... If you just need to run it for 30-seconds every 12-bours, you don't need time-of-day. But, the Arduino's clock/oscillator drifts more than an RTC module so you might have to reset it every week, or so. And with a RTC you could more-easily make it user-programmable, whereas without one, you'll probably have to change the Arduino program to modify the feeding cycle.
P.S.
With ab RTC you'd also need an LCD display, and more buttons.
With a gearmotor and without an RTC your software could be super-simple... Just the Blink Example with longer on-time and much-longer off-time.
That's a fantastic and heartwarming project you're working on to help the stray cats! Here's a basic plan to get you started with your automated cat feeder using an Arduino Nano and a 28BYJ stepper motor:
Components You'll Need:
Arduino Nano (or similar)
28BYJ Stepper Motor with ULN2003 Driver Board
RTC (Real-Time Clock) Module (such as DS3231)
3D-Printed Feeder with Auger
Batteries or Power Supply
Steps to Get Started:
1. Assemble the Hardware:
Connect the 28BYJ stepper motor to the ULN2003 driver board.
Connect the driver board to your Arduino Nano. You'll need to connect the motor pins to appropriate pins on the Nano (usually 4 pins for motor control).
2. Set Up the RTC:
Connect the RTC module to your Arduino. The DS3231 RTC module uses I2C communication and can be powered directly from the Arduino.
Install the RTC library for Arduino, if not already installed, to help manage time. You can do this through the Arduino IDE's Library Manager.
3. Code Your Feeder:
Write an Arduino sketch (code) to control the stepper motor based on the time you want to dispense food. You'll need to consider the following:
Set the feeding schedule (e.g., twice a day).
Calculate the time intervals between feedings.
Use the RTC library to read the current time and compare it to your schedule.
When it's feeding time, activate the stepper motor to dispense food. You'll need to control the stepper motor rotation to dispense a specific amount of food.
4. Power Supply:
For running your cat feeder on batteries for a week, you'll need a power-efficient setup. Regular alkaline batteries may not last long, so consider using rechargeable batteries or a larger battery pack.
You can also explore low-power modes for your Arduino Nano to reduce power consumption when it's not actively feeding.
5. Test and Refine:
Test your setup thoroughly to ensure it dispenses food accurately according to the schedule.
Make any necessary adjustments to the code and hardware based on your testing.
6. Enclosure:
Consider enclosing the entire system in a weather-resistant housing to protect it from the elements, as it will be used outdoors.
Remember, building and coding such a project can be a learning experience, and you might encounter challenges along the way. Be patient and enjoy the process of creating a useful device for your furry friends. Good luck with your cat feeder projects
