Pato is a little green bird who Jorge Rancé found, injured, on the street in Barcelona, and rescued. He was in a bad way, with a broken leg and the feathery equivalent of a terrible hair day.
Pato after a visit to the vet, his broken leg in plaster
Jorge took Pato to the vet to be patched up, and took him home to recuperate in a large birdcage at his house. But he worried that he wouldn’t be there to oversee Pato’s recovery while he was at work. Fortunately, Jorge has a Raspberry Pi. So, using a Pi-Face to interface between the Pi and some sensors, he set up PATOSS: Pato Surveillance System. Now Jorge (and you) can check out how Pato is doing from anywhere in the world.
PATOSS monitors Pato’s recovery by streaming video of what he’s up to to the web, checks on the ambient temperature and the water levels in his little dish, and tweets once an hour to let Jorge know whether everything’s as it should be, with a live picture from Pato’s webcam. The data is transmitted via a wifi dongle.
(If you’re following the PATOSS feed today, don’t panic; Jorge says that the water level monitor is not currently hooked up, so it’s reporting low levels, but Pato does actually have plenty to drink.)
This sort of build is easy to replicate at home. We think it’s a particularly good project for kids with small pets at home who want to apply some computer science to something they really care about. They’ll be able to see real-world results and share them with friends: what could be better than being able to check up on Woffles the hamster’s daily grind via Twitter from school? If you and your children’s pets end up using a PATOSS system at home, please let us know – I’d love to share your results!
We’ve see a lot of clever irrigation devices for gardeners being made with the Pi, but PiPlanter is the most complete (and the best documented) system we’ve seen so far. It does far more than simple irrigation. PiPlanter monitors temperature, ambient light, ambient humidity and soil humidity; it outputs that data to a MySQL database, controls a pump to water the plants depending on that data, and outputs the data as graphs and text. (It also tweets that text and uploads the graphs to Flickr hourly so that Devon, the PiPlanter’s owner, can keep an eye on things.)
Devon has documented the build minutely, with circuit diagrams, a ton of code, and several videos. Here, he explains more about the sensor array he built.
Here’s a weekend project from Dave Hunt for dog owners whose best friends can’t work out whether they want to be inside or outside.
Dave came up with Pi-Rex when the sleep deprivation caused by his new dog barking to be let in or out alternately became too much to bear. She tends to do it at the same time every morning. Dave says: “I could do this with a timer switch and a door strike, but where’s the fun in that?” Indeed, Dave. So instead, he’s made a door that responds to barking. Barking.
You absolutely have to watch the video. I’m not sure whether I enjoyed Dave’s dog impression or his reaction to the door opening the most, but the combined effect had me snorting coffee.
A noise detection circuit tuned to respond to loud dog sounds fires a motor which unlocks the door, and a weight (actually a large bird feeder) and pulley system swings the unlocked door open. Dave says: “I picked up the audio detection circuit in Maplin as a DIY kit for €9.99, the kind of ones where you get all the components and a PCB in a bag, and solder them all together. It took about 30 minutes, but worked perfectly; I could bark, and the LEDs would light as I barked. My family thought I was gone mad when they heard me making dog noises in my workshop.”
Dave, this is magnificent work.
If you want to set up Dave’s dog-operated system in your own house, head over to his website, where all the code you’ll need, some wiring instructions and a parts list are available. He suggests you might like to sample the audio collected and make the door respond to…known barks. I do have one question, Dave: have you trained the dog to shut the door behind herself yet?
In industrial applications, controlling relays, servos, solenoids, and the like isn’t just a matter of wiring in an Arduino and plugging in some code. No, for reliable operation you’ll need a PLC – a programmable logic controller – to automate all your hardware. PLCs are usually pretty expensive pieces of hardware, which led [Warwick] to come up with his own. He built two versions, one large and one small that can handle just about any task thrown at them.
Both devices are powered by an ATMEL SAM7S ARM chip running at 48 MHz. The smaller of the two devices has 10 digital inputs, 4 analog inputs, and 8 digital outputs able to sink 200 mA each. The larger PLC has 22 digital ins, 6 analog ins, and 16 digital outputs. Both of these devices have a ton of connectivity with USB, RS-232 and RS-485 ports
Below you can see the large PLC being used as a barcode scanner and as a strange device using compressed air to levitate a ping-pong ball. There’s also a demo of the smaller PLC lighting up some LEDs.
Mooncake, the Official Raspberry Pi Cat, is fed biscuits twice a day by an off-the-shelf cat-feeding robo-hopper that we bought before Raspberry Pi was a reality. (She also gets that horrible-smelling cat food in gravy from a packet, served up by real live humans.) I’ve just found out what to replace the robot with when it breaks.
Mooncake, well-nourished, “helping” us to dispatch fund-raising stickers
Dave at Twin Cities Maker has made a Pi-powered cat-feeding robot which dispenses two sorts of biscuits, so your fickle pet has a choice of different liver-flavoured kibbles throughout the day.
Dave’s cat feeder, with toaster for scale
It’s much more functional than the one I bought from the pet shop years ago; for a start, it’s wi-fi enabled, so it can be sent instructions remotely. And Dave has plans for making it even whizzier, with sound clips (Cat from Red Dwarf), a camera and a mobile webUI.
Work in progress: this is an Adafruit PermaProto with a couple of solder bridges at the top left. Instructions are on Dave’s blog.
We’re looking forward to see what additions Dave develops for the feeder. Seriously; if you can make this thing self-cleaning, Dave, you can sit back and never have to work again. Cat owners the world over will be banging your door down.
Jon Wise mailed Eben last night to tell us about a 3D printing project he’s been working on, and we thought it was so great we watched the video three times before going to bed. If you’ve ever used a 3D printer you’ll know that they need regular calibrating to make sure that the output is accurate. You have to ensure that various parts are parallel and orthogonal to each other, or your 3D object is likely to come out wonky; things are moving around on three axes, and usually you’ll be doing that calibration by hand.
Jon is sick of hand-calibrating, so he’s used a Pi to do the work for him. This video is a demonstration of how his setup works, using a pencil instead of the usual extrusion nozzle so you can better see what’s going on.
We got talking to Jon about how significant he thought the improvement in resolution you can get from automating calibration might be. He said:
I do not see it as competition to a machine tool approach, but for building products in new areas. I have a friend who would like to build edible products and this was one of the prompts to try alternative layouts – it would be easier to clean icing sugar off the flat base plate than from belts and bearings and the build platform could go into the dish-washer.
The design could be easily scaled by running on a large sheet of material as the arms are light and take no bending forces. The overall size will be big compared to the product but all designs have some down-sides. The key aspect is that anyone can make it. The rack and pinion bits are available from hobby stores and can be linked to any length. The motors come from old printers. There isn’t anything else.
We think this project is great. Using computing to automate repetitive tasks like this frees up time to use your brain to do other more interesting things, and leaves you more productive and more cheerful. It’s one of the reasons we think that giving everybody the opportunity to learn how to do this stuff is so important. What have you automated recently?
Presented without comment, because it’s perfect as it is. Thanks to John (would you believe this is his first ever bit of Python?), and thank you Judd! Python script and CAD design are available at NYCCNC.
Coffee and computing go hand in hand. The world’s first live streaming webcam was pointed at a coffee pot in the Cambridge University Computer Lab’s Trojan Room (yes, Americans, I know you think that sounds funny), back in the days when it was on a shared site in the centre of Cambridge and none of us had even heard of the internet.
It was 1991. A young Quentin Stafford-Fraser was researching ATM networks in the Trojan Room, and drinking too much coffee. Other people in the lab also liked fresh coffee, but there was only one coffee machine between 15 researchers, it was a long walk up an awful lot of stairs to get to the Trojan Room, and all too often, the pot was empty and the walk upstairs wasted. (I think “wasted” is pushing it a bit far. Quentin’s very good conversation.)
Ever practical, Quentin pointed a camera at the Trojan Room coffee pot, hooked it up to a video frame grabber the ATM researchers were using, got Paul Jardetzky to write some server software, and wrote the client software for it himself. Researchers downstairs could now ping the coffee pot to see whether there was anything in it. “The image was only updated about three times a minute, but that was fine because the pot filled rather slowly, and it was only greyscale, which was also fine, because so was the coffee.”
Quentin didn’t realise it at the time, but he had laid the grounds (badoom tish) for the world’s first webcam. In 1993, the <img> tag was added to HTML, meaning you could embed pictures on a webpage. The same year, two more researchers at the lab, Dan Gordon and Martyn Johnson, made changes to the original coffee pot setup to allow it to respond to requests from the internet, and xcoffee became the first ever live webcam.
The Trojan Room Coffee Pot stayed in place (and maintained an online presence: in 1996 it got its millionth hit, and journalist Steve Farrar noted that it had had more ‘visitors’ than King’s College Chapel and was therefore the number one tourist attraction in East Anglia) until 2001, when the University Computer Lab was moved out of its ramshackle old site to a shiny new building in West Cambridge. I was lucky enough to be at the university just before the move, and drank a couple of cups of coffee from the machine, courtesy of friends at the lab. (Quentin is right about the greyscale thing. Historic it might have been, but it was bloody awful coffee.) Eventually, the pot was auctioned on eBay to raise money for coffee-making in the new lab; Der Spiegel Online bought it for £3350. Apparently, Krups refurbished it free of charge, and it’s still making greyscale coffee for an office full of German journalists.
Anyway. This long preamble doesn’t have much to do with the Pi. (About an hour after I originally posted this, Barney Livingston pointed out on Twitter that The Trojan Room Coffee Server was an Acorn Archimedes, so shares its ARM processor heritage with the Pi.) But it does demonstrate that projects involving coffee and computers have a long and storied history in this part of the world. Technology has moved on, but the coffee is still supremely important. So Sacha Wolter from Deutsche Telekom has incorporated a Raspberry Pi into his coffee machine. It’s a bit more sophisticated than the Trojan Room Coffee Pot; Sacha’s coffee machine rings him up when the coffee’s ready, and if Sacha places a call to the machine, it’ll get a pot ready for his arrival.