It is hardly news that you can use your smart phone as a really crummy oscilloscope. You can even use it as an audio frequency signal generator. There are also plenty of projects that allow you to buffer signals going in and out of your phone to make these apps more useful and protect your phone’s circuitry to some degree. What caught our eye with [loboat’s] phone oscilloscope project was its construction.
Although scientists have known about Ultra-High Energy Cosmic Rays (UHECRs) for years, nobody can pinpoint their origin. When these UHECRs hit the ground, however, they cause a widespread local disturbance called an air shower. This air shower is a wide dispersion of photons, muons, and electrons at sea level. The means of observing this air shower mandates a widespread geographic region for detecting them. One solution would be a very big detector. Physicists [Daniel] and [Michael] discovered an alternative to pricey hardware, though. By leveraging the CMOS sensors in our smartphones, they can borrow some CPU cycles on our phones to create a worldwide detector network.
According to their paper, the CMOS camera in our smartphones is sensitive to the spectrum of radiation induced by muons and photons from these air showers. With an app running on our phones, [Daniel], [Michael], and other scientists can aggregate the data from multiple detections in a similar region to better understand their origins.
If you’re concerned about CRAYFIS taking away from your talk or web-browsing time, fear not; it runs in the background when a power source has been detected, hopefully, when you are asleep. It’s not the first time we see scientists tap into our computing resources, but this is certainly an achievement made possible in only the last few years by the sensor-loaded smartphone that charges on many of our night stands. With over 1.5 billion smartphones active in the world, we’re thrilled to see a team cleverly leveraging a ubiquitous and already-well-distributed resource.
There’s something so nostalgic about the rotary phone that makes it a fun thing to hack and modernize. [Voidon] put his skills to the test and converted one to VoIP using a Raspberry Pi. He used the RasPi’s GPIO pins to read pulses from the rotary dial – a functional dial is always a welcome feature in rotary phone hacks. An old USB sound card was perfect for the microphone and handset audio.
As with any build, there were unexpected size issues that needed to be worked around. While the RasPi fit inside the case well, there was no room for the USB power jack or an ethernet cable, let alone a USB power bank for portability. The power bank idea was scrapped. [voidon] soldered the power cord to the RasPi before the polyfuse to preserve the surge protection, used a mini-USB wifi dongle, and soldered a new USB connector to the sound card. [Voidon] also couldn’t get the phone’s original ringer to work, so he used the Raspberry Pi’s internal sound card to play ringtones.
The VoIP (SIP) was managed by some Python scripting, available at GitHub. [voidon] has some experience in using Asterisk at his day job, so it will be interesting to see if he incorporates it in the future.
Internet connected cameras are mighty useful, specially in situations requiring some form of remote monitoring. An always-on camera that is available over an internet connection, is cheap, and uses re-purposed hardware – that’s what the Gonzo project hopes to achieve. To accommodate these requirements, the Exploratory Engineering program team in Telenor Digital are using off-the-shelf phone hardware running on top of a fork of Firefox OS. You hang the Gonzo where you want to monitor a situation, after which it will function for up to one month before needing a recharge, sending data to a designated public URL over the 2G network.
A big downside with using such hardware is that it is not designed for the task at hand, and offers no expansion ports that may be needed for certain functions. In this particular case, the designers needed a couple of output ports to drive some LED’s. The hardware guys got a bit creative, and re-mapped the volume buttons of the phone into generic GPIO ports. On the software side, they looked at where the button GPIO’s were referenced, and located how they are mapped to a keymap. They then added a device driver that maps the GPIO ports to be generic ports instead. Modding the hardware needed a little bit more hard work, figuring out which traces connected to the two volume buttons, adding series resistors, and then wiring the LED’s in place. The project itself is still a work in progress, and you can read more about it at the Gonzo website.
If you’re like one of us and have a box full of old phones lying around, take a look at some creative suggestions here for some Arduino controlled robots.
Thanks for the tip [pb] !
Payphones used to be found on just about every street corner. They were a convenience, now replaced by the ubiquitous mobile phone. These machines were the stomping grounds for many early computer hackers, and as a result hold a place in hacker history. If you’ve ever wanted to re-live the good ol’ days, [hharte’s] project might be for you.
[hharte] has been working to make these old payphones useful again with some custom hardware and software. The project intends to be an interface between a payphone and an Asterisk PBX system. On the hardware side, the controller board is capable of switching various high voltage signals required for coin-line signaling. The controller uses a Teensy microcontroller to detect the hook status as well as to control the relays. The current firmware features are very basic, but functional.
[hharte] also wrote a custom AGI script for Asterisk. This script allows Asterisk to detect the 1700hz and 2200hz tones transmitted when coins are placed into the machine. The script is also in an early stage, but it will prompt for money and then place the call once 25 cents has been deposited. All of the schematics and code can be found on the project’s github page.
[Daniel Whiteson and Michael Mulhearn], researchers at the University of California, have come up with a novel method of detecting ultra-high energy cosmic rays (UHECR) using smartphones. UHECR are defined as having energy greater than 1018eV. They are rare and very difficult to detect with current arrays. In order to examine enough air showers to detect UHECR, more surface area is needed. Current arrays, like the Pierre Auger Observatory and AGASA, cannot get much larger without dramatically increasing cost. A similar THP Quarterfinalist project is the construction of a low-cost cosmic ray observatory, where it was mentioned that more detection area is needed in order to obtain enough data to be useful.
[Daniel Whiteson and Michael Mulhearn] and colleagues noted that smartphone cameras with CMOS sensors can detect ionizing radiation, which means they also will pick up muons and high-energy photons from cosmic rays. The ubiquitous presence of smartphones makes their collective detection of air showers and UHECR an intriguing possibility. To make all this happen, [Whiteson and Mulhearn] created a smartphone app called CRAYFIS, short for Cosmic RAYs Found In Smartphones. The app turns an idle smartphone into a cosmic ray detector. When the screen goes to sleep and the camera is face-down, CRAYFIS starts taking data from the camera. If a cosmic ray hits the CMOS sensor, the image data is stored on the smartphone along with the arrival time and the phone’s geolocation. This information is uploaded to a central server via the phone’s WiFi. The user does not have to interact with the app beyond installing it. It’s worth noting that CRAYFIS will only capture when the phone is plugged in, so no worries about dead batteries.
The goal of CRAYFIS is to have a minimum of one million smartphones running the app, with a density of 1000 smartphones per square kilometer. As an incentive, anyone whose smartphone data is used in a future scientific paper will be listed as an author. There are CRAYFIS app versions for Android and iOS platforms according to the site. CRAYFIS is still in beta, so the apps aren’t publicly available. Head over to the site to join up!
The Pogoplug Series 4 is a little network attached device that makes your external drives accessible remotely. Under the hood of this device is an ARM processor running at 800 MHz, which is supported by the Linux kernel. If you’re looking to build your own PBX on the cheap, [Ward] runs us through the process. Since the Pogoplug 4 is currently available for about $20, it’s a cheap way to play with telephony.
Step one is to convert the Pogoplug to Debian, which mostly requires following instructions carefully. After the Pogoplug is booting Debian, the Incredible PBX bundle can be installed. We’ve seen this bundle running on a Raspberry Pi in the past. Incredible PBX’s preconfigured setup based on Asterisk and FreePBX gives a ton of functionality out of the box.
With your $20 PBX running, there’s a lot that can be done. Google’s Voice service allows unlimited free calling to the USA and Canada. With Internet connectivity, you get email notifications for voicemails, and can query WolframAlpha by voice.