A Tweeting Litter Box

SmartLitterBox

How can you not be interested in a project that uses load cells, Bluetooth, a Raspberry Pi, and Twitter. Even for those of our readers without a cat, [Scott's] tweeting litter box is worth the read.

Each aspect of this project can be re-purposed for almost any application. The inexpensive load cells, which available from eBay and other retailers, is used to sense when a cat is inside the litter box. Typically sensors like the load cell (that contain a strain gauge) this use a Wheatstone bridge, which is very important for maximizing the sensitivity of resistive sensor. The output then goes to a HX711, which is an ADC specifically built for load cells. A simple alternative would be using an instrumentation amplifier and the built-in ADC of the Arduino. Now, the magic happens. The weight reading is transmitted via an HC-06 Bluetooth module to a Raspberry Pi. Using a simple Perl script, the excreted weight, duration, and the cat’s resulting body weight is then tweeted!

Very nice work! This is a well thought out project that we could see being expanded to recognize the difference between multiple cats (or any other animal that goes inside).

Motion sprinkler chases away defecating dogs

Don’t want dogs pooping on the front lawn? You could put up a sign, your could chase them away like a crotchety old miser, or you could build a motion detecting sprinkler system. It’s pretty hard to line up for a doody when you’re getting sprayed in the face (or worse) with cold water.

The setup is pretty simple. The bump-in image above shows the view from a webcam. The server monitoring the video is running software that detects motion between one frame and the next. When it sees something in the right position it signals an Arduino to trigger the solenoid which has been holding back the water. Check out the movie after the break which shows [Phil Tucker] tramping across the grass to trigger the  trap.

Sprinkler hacks are always a lot of fun. This variable-range sprinkler is still one of our favorites.

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Break out the two-ply, Ecobot III poops

Imagine our surprise when this article on Ecobot III and the disgusting video above showed up in our feed. The robot can theoretically be self-sustaining forever, so long as it has a food source. Yes, you read correctly, food.

Typical robots relying on grub burn the biomass to produce heat/steam/energy, but Ecobot III actually digests using Microbial Fuel Cells and extracts energy in the form of hydrogen.

The process isn’t very efficient (yet), and of course waste must be excreted, but we’re inching closer and closer to the day our robot overlords are invincible. The project has come to a halt (we can’t imagine why), but you can still read up on the process, and meet Ecobot’s brothers: II and I.

Related: We’re all going to die, Carnivorous robots.