Feral cats are a huge problem in some areas. Roaming freely in cities and in rural settings and reproducing with reckless abandon, colonies of feral cats can exhibit nuisance behavior that often results in unpleasant measures being taken to control their population. More humane programs, such as trap-neuter-return (TNR), seek to safely trap cats, give them basic vaccinations and neuter them, and either return them to their colony or, for a lucky few, ready them for adoption. Such programs are proving successful, but are not without issues. Enter Das Katzetelegraf.
You don’t need to understand a lick of German to figure out exactly what Das Katzetelegraf does from its name. Consisting of an Arduino, a GSM module, and a simple magnetic reed switch attached to the door of a humane cat trap, Das Katzetelegraf sends a text message to a TNR program volunteer when a cat has been trapped. Instead of waiting in the trap for the TNR workers to make daily rounds, the cats are quickly retrieved and the trap is reset for the next cycle. This reduces the time the cat spends in the trap, stressed and without access to food or water, and improves the animal’s outcome. As a bonus, each trap’s throughput is increased, so more animals can be cycled through the TNR program.
TNR can really help reduce feral cat populations, and Das Katzetelegraf can make them even more effective. But if you just have a stray cat pooping up your garden, a Raspberry Pi cat-deterring sprinkler might be a better choice.
A car from 1940 would have been an almost completely mechanical device. These days though, a car without electricity wouldn’t run. It’s not the engine – it’s the computers; the design details of which automotive manufacturers would love to keep out of the hands of hardware hackers like us. [Mastro Gippo] wanted to build a small and powerful CAN bus reverse engineering tool, and the Crunchtrack hits it out of the park. It’s a CAN bus transceiver, GPS receiver, and GSM modem all wrapped up into a single tiny device that fits under your dash.
[Mastro] has a slight fetish for efficiency and tiny, tiny devices, so he’s packaging everything inside the shell of a standard ELM327 Bluetooth adapter. This is a device that can fit in the palm of your hand, but still taps a CAN bus (with the help of a computer), receives GPS, and sends that data out over cell phone towers.
The device is based on the STM32 F3 ARM microcontroller (with mbed support), a ublox 7 GPS module, and an SIM800 GSM module, but the story doesn’t stop with hardware. [Mastro] is also working on a website where reverse engineering data can be shared between car hackers. That makes this an excellent Hackaday Prize entry, and we can’t wait to see where it goes from here.
There are numerous instances where we need to know our location, but cannot do so due to GPS / GSM signals being unavailable and/or unreachable on our Smart Phones. [Blecky] is working on SubPos to solve this problem. It’s a WiFi-based positioning system that can be used where GPS can’t.
SubPos does not need expensive licensing, specialized hardware, laborious area profiling or reliance on data connectivity (connection to database/cellphone coverage). It works independently of, or alongside, GPS/Wi-Fi Positioning Systems (WPS)/Indoor Positioning Systems (IPS) as an additional positioning data source by exploiting hardware commonly available.
As long as SubPos nodes are populated, all a user wishing to determine their location underground or indoors needs to do is use a Wi-Fi receiver. This can be useful in places such as metro lines, shopping malls, car parks, art galleries or conference centers – essentially anyplace GPS doesn’t penetrate. SubPos defines an accurate method for subterranean positioning in different environments by exploiting all the capabilities of Wi-Fi. SubPos Nodes or existing Wi-Fi access points are used to transmit encoded information in a standard Wi-Fi beacon frame which is then used for position triangulation.
The SubPos Nodes operate much like GPS satellites, except that instead of using precise timing to calculate distance between a transmitter and receiver, SubPos uses coded transmitter information as well as the client’s received signal strength. Watch a demo video after the break.
Continue reading “Hackaday Prize Entry : Subterranean Positioning System”
For [Tyler]’s entry to the Hackaday Prize, he’s making something that just a few years ago would be unheard of in a homebrew build. He’s making a DIY smartphone. Yes, with cheap single-board Linux computers, GSM modules, and SPI touchscreen displays, it’s possible to build your own smartphone.
Inside [Tyler]’s DIY smartphone is a Raspberry Pi Model A, a 3.5 inch touchscreen PiTFT with 480×320 resolution, and an Adafruit FONA module The connections are simple enough; the TFT is connected over SPI, and the GSM module over serial. The entire device is powered by a 1200mAh LiIon battery, charged with a powerboost board, runs an operating system written in Python capable of making calls, sending texts, and takes pictures with a Pi camera.
This is not what you would normally call a smartphone. The FONA module is 2G only, meaning you’re limited to 2G speeds and 2G networks. AT&T will be shutting down 2G networks in a little bit, although T-Mobile will be keeping them up for anyone who still has an old Nokia Brick.
That said, [Tyler]’s phone is still exactly what you want in a minimal phone: it just makes calls and receives texts, it has a camera, and unlike the Nokia, you can take it apart and repair it easily. Not that you ever had to do that with a Nokia…
Looking for a way to track your high-altitude balloons but don’t want to mess with sending data over a cellular network? [Zack Clobes] and the others at Project Traveler may have just the thing for you: a position-reporting board that uses the Automatic Packet Reporting System (APRS) network to report location data and easily fits on an Arduino in the form of a shield.
The project is based on an Atmel 328P and all it needs to report position data is a small antenna and a battery. For those unfamiliar with APRS, it uses amateur radio frequencies to send data packets instead of something like the GSM network. APRS is very robust, and devices that use it can send GPS information as well as text messages, emails, weather reports, radio telemetry data, and radio direction finding information in case GPS is not available.
If this location reporting ability isn’t enough for you, the project can function as a shield as well, which means that more data lines are available for other things like monitoring sensors and driving servos. All in a small, lightweight package that doesn’t rely on a cell network. All of the schematics and other information are available on the project site if you want to give this a shot, but if you DO need the cell network, this may be more your style. Be sure to check out the video after the break, too!
Continue reading “APRS Tracking System Flies Your Balloons”
The Spark Electron was released a few days ago, giving anyone with the Arduino IDE the ability to send data out over a GSM network. Of course, the Electron is just a GSM module tied to a microcontroller, and you can do the same thing with a Pi, some components, and a bit of wire.
The build is fairly basic – just an Adafruit Fona, a 2000 mah LiPo battery, a charge controller, and a fancy Hackaday Perma-Proto Hat, although a piece of perf board would work just as well in the case of the perma-proto board. Connections were as simple as power, ground, TX and RX. With a few libraries, you can access a Pi over the Internet anywhere that has cell service, or send data from the Pi without a WiFi connection.
If you decide to replicate this project, be aware you have an option of soldering the Fona module right side up or upside down. The former gives you pretty blinking LEDs, while the latter allows you to access the SIM. Tough choices, indeed.
One day, [Samy]’s best friend [Matt] mentioned he had a wireless doorbell. Astonishing. Even more amazing is the fact that anyone can buy a software defined radio for $20, a small radio module from eBay for $4, and a GSM breakout board for $40. Connect these pieces together, and you have a device that can ring [Matt]’s doorbell from anywhere on the planet. Yes, it’s the ultimate over-engineered ding dong ditch, and a great example of how far you can take practical jokes if you know which end of a soldering iron to pick up.
Simply knowing [Matt] has a wireless doorbell is not enough; [Samy] needed to know the frequency, the modulation scheme, and what the doorbell was sending. Some of this information can be found by looking up the FCC ID, but [Samy] found a better way. When [Matt] was out of his house, [Samy] simply rang the doorbell a bunch of times while looking at the waterfall plot with an RTL-SDR TV tuner. There are a few common frequencies tiny, cheap remote controls will commonly use – 315 MHz, 433 MHz, and 900 MHz. Eventually, [Samy] found the frequency the doorbell was transmitting at – 433.8 MHz.
After capturing the radio signal from the doorbell, [Samy] looked at the audio waveform in Audacity. It looked like this doorbell used On-Off Keying, or just turning the radio on for a binary ‘1’ and off for a binary ‘0’. In Audacity, everything the doorbell transmits becomes crystal clear, and with a $4 434 MHz transmitter from SparkFun, [Samy] can replicate the output of the doorbell.
For the rest of the build, [Samy] is using a mini GSM cellular breakout board from Adafruit. This module listens for any text message containing the word ‘doorbell’ and sends a signal to an Arduino. The Arduino then sends out the doorbell code with the transmitter. It’s evil, and extraordinarily over-engineered.
Right now, the ding dong ditch project is set up somewhere across the street from [Matt]’s house. The device reportedly works great, and hopefully hasn’t been abused too much. Video below.
Continue reading “Over-engineering Ding Dong Ditch”