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.
[yoyotechKnows] built an Alexa-controlled garage door opener after his Liftmaster stopped working. Now all he has to do is holler at his mobile phone and he can raise and lower his garage doors at will.
His project is based around a Photon WiFi kit, with a pair of LCC 120 digital relays triggering the two doors, reed switches, and a serial-equipped LCD to display door status, with Alexa, IFTTT, and OpenHab to process the commands. You can find his code in the project writeup.
Currently he has a LCD display informing him of the status of each door, hot glued a reed switch to keep track of whether each one is closed. This might seem a little bit extraneous since he can also just look at the doors from within the garage. However, he’s thinking about putting the display inside his house. But couldn’t he just ask Alexa?
We love us our home automation here at Hackaday, with everything from swimming pools to chicken coops rigged for app control and datalogging.
Continue reading “Have Alexa Open Your Garage Door”
[Lucid Science] shows us how to make some simple reed switches. Reed switches are simple components that detect a magnetic field and can close or open a circuit once detected. While not really a thing of beauty, these DIY reed switches should help you out if you just can’t wait to order some or you fancied trying your hands at making some components from scratch.
Reed switches normally come in very small form factors so if you need something small then this may not be for you however the video does show you on a macro scale the fundamental workings of a reed switch. To make your own reed switch you need only a few parts: some copper, enamelled wire and magnets. They really are simple devices however sometimes it’s easy to overlook how simple some things are when they are so small that you can’t really see how they work.
Making your own components from scratch is probably the best way to understand the inner workings of said component. In the past we have seen some pretty awesome self built components from these beautiful DIY Nixie tubes to even making your own LEDs
Continue reading “Make Your Own Reed Switches”
I had a small project going on–never mind exactly what–and I needed to detect a magnet. Normally, that wouldn’t be a big problem. I have a huge hoard of components and gear to the point that it is a running joke among my friends that we can be talking about building something and I will have all the parts we need. However, lately a lot of my stuff is in… let’s say storage (again, never mind exactly why) and I didn’t have anything handy that would do the job.
If I had time, there are plenty of options for detecting a magnet. Even if you ignore exotic things like SQUID (superconducting quantum interference device) there’s plenty of ways to detect a magnet. One of the oldest and the simplest is to use a reed switch. This is just a switch made with a thin piece of ferrous material. When a magnet is nearby, the thin piece of metal moves and makes or breaks the contact.
These used to be common in alarm systems to detect an open or closed door. However, a trip to Radio Shack revealed that they no longer carry things like that as–apparently–it cuts into floorspace for the cell phones.
I started to think about robbing a sensor from an old computer fan or some other consumer item with a magnetic sensor onboard. I also thought about making some graphene and rolling my own Hall effect sensor, but decided that was too much work.
I was about to give up on Radio Shack, but decided to skim through the two cabinets of parts they still carry just to get an idea of what I could and could not expect to find in the future. Then something caught my eye. They still carry a wide selection of relays. (Well, perhaps wide is too kind of a word, but they had a fair number.) It hit me that a relay is a magnetic device, it just generates its own electromagnetic field to open and close the contacts.
I picked up a small 5 V reed relay. They don’t show it online, but they do have several similar ones, so you can probably pick up something comparable at your local location. I didn’t want to get a very large relay because I figured it would take more external magnetic field to operate the contacts. You have to wonder why they have so many relays, unless they just bought a lot and are still selling out of some warehouse. Not that relays don’t have their use, but there’s plenty of better alternatives for almost any application you can think of.
Continue reading “Sensing a Magnet with Local Sourcing”
[Mike Diamond] was tired of climbing down (and back up) 40 stairs to check his mailbox. He decided to create a mailbox alert using the ESP8266 to connect to his WiFi. The idea was simple: have the ESP8266 monitor when the mailbox flap opened using a magnet and a reed switch. As always, though, the devil is in the details. [Mike] got things working with a little help and shares not only the finished design but how he got there.
To handle the sending of e-mail, [Mike] used the Blynk app. You often think of Blynk as a way to build user interfaces on an Android or iOS device that can control an Arduino. In this case, though, [Mike] used the library with the ESP8266 and had it send e-mail on his behalf.
Continue reading “Avoiding Exercise with an ESP8266 and Blynk”
Sitting on the beach, finishing off a beer one day, [Rulof] realized that if he put a motor in the beer bottle with a propeller at the bottle’s mouth, he could attach the result to his leg and use it to propel himself through the water. Even without the added bonus of the beautiful Mediterranean waters through which he propels himself, this is one hack we all wish we’d thought of.
These particular beer bottles were aluminum, making cutting them open to put the motor inside easy to do using his angle grinder. And [Rulof] made good use of that grinder because not only did he use it to round out parts of the motor mounting bracket and to cut a piston housing, he also used the grinder to cut up some old sneakers on which he mounted the bottles.
You might wonder where the pistons come into play. He didn’t actually use the whole pistons but just a part of their housing and the shaft that extends out of them. That’s because where the shaft emerges from the housing has a water tight seal. And as you can see from the video below, the seal works well in the shallow waters in which he swims.
Continue reading “Leg Mounted Beer Bottles for Underwater Propulsion”
This laser-cut lamp is an awesome example of what you can do with a laser cutter and a bit of creativity. It was completely laser cut and features no fasteners, except for a bit of glue.
[PaisleyGarbage] has been making lamps for a while now and had the concept for this one early on. After rendering a model of it on the computer, he decided it was finally time to try making it. It wasn’t quite as easy as he thought it’d be, but the challenges along the way only help you to learn when doing a project like this.
He laser cut alternating strips of wood and acrylic to create the unique sandwiched light look of the final product. Instead of using fasteners or anything, he even slid the pieces together on acrylic dowels keeping the design as minimalist and clean as possible. But the part we really like is the magnetic switch.
Continue reading “Laser-Cut Lamp With Magic Switch”