Nothing is ever as simple as first seems.

Although my new Wireless Cat Feeder has been operating brilliantly, the cat was still often waking us up for pre-dawn breakfast.  Although I would grab my phone from the bedside table and hit the ‘Feed Cat’ button, the cat was unable to grasp the concept that food was now available since the people didn’t get out of bed and get it for him.

In the past we had established a kind of Pavlov’s Dogs association when giving him cat nibbles.  We would shake the bag of cat nibbles before putting some on the plate.  The noise of the bag being shaken would get him running over every time.

So I wondered was there a way to include this in my solution…?

I had picked up an MP3 player/ trigger board from Sparkfun a couple of weeks earlier for another project but didn’t need it straight away.  I saw an opportunity to re-hack my Cat Feeder, add in the ability to play an MP3 recording of the cat food bag being shaken, wait a second, then trigger the food.

This clever board has a built-in MP3 player plus support for playing sounds based on either commands though a serial connection or by bridging one of 18 trigger pins on the board.  Shorting the pins for Trigger 1 would play a file on the SD card with a filename starting 001.

The modifications were quickly made: 5V power to the MP3 Trigger board, SD card loaded with the relevant sound effect with filename 001catfeeder.mp3, a transistor connected to the relevant trigger pins with the base connected to another GPIO pin on the RN-XV.  I modified the PHP script a bit to send the telnet command to power on/off the GPIO pin for the MP3 player, wait a second, then trigger the cat feeder as before.

The setup inside the Cat Feeder was a bit ugly, but I was hoping I would only need the sound effect for a week or two then remove once the cat had also associated the mechanical sound of the dispenser with food.  Speakers were external, connected by a short mini-stereo cable from the MP3 trigger board running out through the dispenser tube to speakers hidden behind the unit.

Once all set up it was time to test it.  I pressed the ‘Feed Cat’ button on my phone, the shaking bag sound played, the cat food came out and the cat came trotting over to have some nibbles!

In the end I only had to run the enhanced version for one week before the cat got used to the idea that food could be made available without the people having to put it there, and went running over even when the bag shaking sound wasn’t being played.

Since I set this up people have suggested I make this a commercial product. Although an interesting idea I don’t think it could be made cheap enough to get to the kind of price point that would get mass market appeal.  As it stands this until represents about $70 in parts.

A commercial version would also need to have a different feature set.  My hacked cat feeder will only work in my house.  It has been configured for my local wifi network only.  If I change my wifi network settings I have to crack open the Cat Feeder to re-configure it.

It also relies on having my web server in the loop.  The ‘Feed Cat’ button is presented on a web page provided by the server.  When pressed the server must telnet to the Cat Feeder to send it the commands to operate.

A commercial version would need an easy way to re-configure the wifi settings, or just work in ad-hoc wifi mode.  There are similar products in the market that use wifi to connect to other devices (eg AR Drone or Withings Scale).  It could be set up so when first setting up the Cat Feeder you download a mobile app you could use to configure your wifi network settings, then place into normal operations mode where the app then connects and sends the operations commands over the local wifi network.

If I ever get around to building a second one to give to someone else I figure this is how I would do it next to make it more user friendly, and plug’n’play!