Hackaday Podcast Ep12: Nearly Perpetual Motion, Mars Rover Carries Kid, And Doc Brown’s Cat Feeder

Editors Elliot Williams and Mike Szczys catch up on the past week in hackerdom. It seems as if we’re in a golden age of machine building as an incredible rocker-bogie rover is built to transport a child and mechanical simplicity automates the wet cat food dispensing process. We marvel at the ability to use G-code to decorate eggs (them being curvy in more than one direction and all). The we contemplate the ability to build and start a motor which will continue to run long after your own life ends. And perhaps it’s time to add more layers to your PCB design playbook.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (52.3 MB)

Places to follow Hackaday podcasts:

Continue reading “Hackaday Podcast Ep12: Nearly Perpetual Motion, Mars Rover Carries Kid, And Doc Brown’s Cat Feeder”

Cat Feeder Has Steampunk Flair And A GMail Account

While it is often said that “necessity is the mother of invention”, we can’t say that’s always been our experience here at Hackaday. You won’t need to search too long before you find a project or hack on this site that definitely falls out of the realm of strict necessity. But that’s part of the fun, there’s a reason this site isn’t called AppropriateUseOfTime.com

But when [Sam Storino] couldn’t seem to stop his cats from howling for their supper at 3:00 AM, he had the perfect opportunity to fulfill that age-old wisdom. Not only did he manage to turn a trip to the plumbing isle of his local home improvement store into a very Steampunk-looking automatic cat feeder, but he also found the time to write up an exceptionally detailed series of blog posts on what he learned during the process.

The heart of the machine is everyone’s favorite Linux board, the Raspberry Pi. You might be thinking the Pi is overkill for a simple timer, and you’d be right. Rather than just dump the food out on a set schedule, [Sam] decided to get a little fancy and come up with some Python scripts that will monitor a GMail inbox and activate the feeder hardware when it receives an email with the title “feed cats”. He then uses IFTTT to send the appropriately named email to the GMail account of his cat feeder on a specific schedule. Hey, nobody said necessity was the mother of straightforward invention.

In the final post of the series, [Sam] goes over the hardware side of the device. Copper pipe makes up the frame, which holds a commercial off-the-shelf dry food dispenser. The feeder was designed for manual operation, but by attaching a continuous rotation servo [Sam] can spin it up and dump a pre-measured amount of food via the Pi’s GPIO pins. The addition of some PVC pipe and fittings takes the food and (at least in theory) divides it equally between the two cat bowls below.

If you think [Sam] may have put a bit more thought than was necessary into something as simple as feeding his pets, keep in mind that he’s in exceptionally good company. Paging through the archives, it seems the intersection of felines and hackers is littered with gloriously complex contraptions.

Opto-Isolating Automatic Cat Feeder Problems

When you buy an off-the-shelf automatic cat feeder, you might well expect it to do the one thing it’s supposed to do. Feed the cat. Well, at least as long as you do your part by keeping it filled with food nuggets. [Stephen] had the sneaking suspicion that his feeder was slacking occasionally, and set out to prove this theory.

He had a few ideas for approaching the investigation. One was to set up a web cam, but that proved unreliable. Another idea was to log the weight changes of the food bowl. This seemed like a possibility because the reading would change dramatically whenever it was filled. The method he settled on is a good one, too — monitor the motor’s activity and look for holes. After all, the motor only runs when it’s feeding time.

The design is based around a smart door/window alarm, which is little more than a reed switch with networking capabilities. [Stephen] wired up an opto-isolator so that when the motor runs, the reed switch is triggered but not fried, and the event gets logged in Google Sheets. Any missed meals are weeded out with a script that alerts [Stephen] via email and text that his poor kitty is hungry.

If [Stephen] ever wants to build his own cat feeder, we have plenty of designs for inspiration.