Hi I am interested in making an automatic cat feeder. The hangup with this project is designing a system that times the feeding properly.

I would like to design a system where:
-Every 12 hours, power is supplied to a motor(for a second or two at most,probably) that turns a blade that dispenses food.
-Is automatic, and doesn't require physical input, as I would be using it while away from my home. (If it is practical, remote input is an option)

Additional Info:
-I have a raspberry pi B Rev 2.1 (picture attached)
-I have a working knowledge of electronics and have left most of the details vague as I have little experience and am open to any suggestions on how to approach this.
-I appreciate your time and help and would be grateful if anyone could give me a nudge in the right direction. Thank you.

 

Instead of the huge cost of of the above project i guess a simple transistor circuit using LDRs to detect sun light movement with appropriate mechanical setup can do the job as well if the timing is long enough to detect sun light movement or to detect darkness i guess it can be achieved with just the fraction of the above......

 

Hi I am interested in making an automatic cat feeder. The hangup with this project is designing a system that times the feeding properly.

I would like to design a system where:
-Every 12 hours, power is supplied to a motor(for a second or two at most,probably) that turns a blade that dispenses food.
-Is automatic, and doesn't require physical input, as I would be using it while away from my home. (If it is practical, remote input is an option)

Additional Info:
-I have a raspberry pi B Rev 2.1 (picture attached)
-I have a working knowledge of electronics and have left most of the details vague as I have little experience and am open to any suggestions on how to approach this.
-I appreciate your time and help and would be grateful if anyone could give me a nudge in the right direction. Thank you.

First step to betaken:
Make a flowchart defining what you want (in detail.)
Define what you don't want to happen and how to handle.
eq the motor should be controlled all times. (feedback is rotating, not rotating or rotation time not conform the given value.
Electrical/software errors should be detected and lead to a defined situation including the error message. (batt backup for mpu allowing error messages radio/cable/internet/gsm whatever is needed)
This forced you into two complete separate systems with separated power supplies and sensors.

After defining all above you can draw-up the circuits and start making programs.

Picbuster

 

I also think an RP is overkill for such a simple task, My first choice would be a plug in mains timer that is set to switch on for a minute which would trigger a 555 timer to give th few seconds pulse. If it needs to be battery powered the electronics in the timer could be powered from an Ni Mh AA cell in place of it's tiny button cell. My second choice would be a small PIC or one of the Atmel ATtiny chips with a 32.768 Khz crystal. (I think even using the internal clock generator on the microcontrller would be accurate enough for your purpose..)

Les.

 

This is a simple timer circuit that I used to turn on a Ozone generator for a short periods at fixed intervals. This circuit was plugged into a standard wall outlet timer that could be set in 15 minute (minimum) ON times. The internal power supply was a gutted wall wart. It should serve you purpose.

Ken

 

I go with Les's first choice.
Use a standard AC powered wall timer (type with battery backup if needed) to power a simple one-shot circuit (555 type if one-shot accuracy is needed) from a wall-wort supply.

For remote control, you could use a WiFi smart plug, which can be purchased for as little as $10 US.
These can be programmed to go on and off at any number of times per day, as well as controlled by a smart-phone app.

 

Thank you all very much for you replies! I am going to work on using Les's approach and i will update the thread with my progress.