I’m creating a project to pull a string when a cat enters a door to cause the door to close behind her. The door is a standard screen door with a standard door closer. I want to prop the door open with a small stick, attach a string between it and one of your 9v solenoids. I’m building a circuit to activate the solenoid when the cat crosses a laser beam….
Thanks for all the help. I ended up using the 24v DC converter/power supply. It worked very well with the solenoid pulling on one end of a stick holding the door open. I had to work on the door to get it to close and latch properly. Here are pics of the final rig (overview, & control center), plus a pic of my cat Stella, safely at home.
We have a massive update on Cats of Engineering, we’re caught up and have added the latest rounds of cats. If you’d like to add your cat just scroll down to the bottom and send a photo (link) in! Pictured above: Test Subject Tigger Reporting for Duty.
Since you’ve done a lot with Apple chargers, I thought you might be interested in my article on the Magsafe connector on Mac chargers. I tore down the charger connector, determined that it communicates with the Mac via the 1-wire protocol and a DS2413 1-wire switch chip, and I used an Arduino to read the charger’s ID and control the status light.
In addition to the obligatory refrigerator full of soda (or sometimes empty of soda, depending on whether anyone’s filled it recently), we also have a water cooler that takes the big 5gal water bottles. They also sell coolers that can be plumbed into a water line, and a while back I discovered that they’re actually bottle-type coolers that come with a conversion kit. The kit consists of a float switch and a solenoid valve, and a mounting bracket that takes the place of the bottle holder.
There isn’t a conversion kit for the cooler we have, but it looked simple enough, so I made one from scratch. I don’t like float switches, so I used two other methods of sensing the water level (I wanted a backup sensor because certain failure modes could result in an unlimited amount of water on the floor, which would be a Bad Thing). Instead of trying to find the “best” way to do it, I used the components I was interested in learning about….
We have a massive update on Cats of Engineering, we’re caught up and have added the latest rounds of cats. If you’d like to add your cat just scroll down to the bottom and send a photo (link) in! Pictured above: Missy guards her Arduino fireflies prototype.
Take caution not to electrocute yourself. A handy multimeter can help ensure that. I use a Fluke multimeter daily, so I based it mostly off that. Built for Iron Builder; the piece for this round is the dark red cone by www.BruceLowell.com
An easy to use, affordable, computer controlled mill. Take all your DIY projects further with custom circuits and precision machining. At Otherfab, we are interested in portable, accessible, computer-controlled machines, and how they can help us design our world. With the ability to make custom circuitry, we can now build our own smart objects – medicine bottles that email reminders, shoes that tell you how fast you went, and even glasses that know when you need to put on sunscreen. The Othermill is our contribution to custom circuit design and the desktop manufacturing revolution.
The Othermill is a portable, computer controlled, 3-axis mill that is specifically designed for use at home or in a small workspace. Our objective is to build a mill that is compact, clean, and quiet enough for use at home, yet is precise enough for high level electrical and mechanical prototyping work. The Othermill will be at home on your desk, in your workshop, or on your kitchen table.