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Taking the Raspberry Pi 2 for a Test Drive with GNU Radio
- morganvachon 12y agoThis is one of the projects I had in mind for the RPi 2. I've already got the RTL-SDR stick and it works great on my workstation, but having it portable would be even better. I'm happy to see that the RPi 2 can handle the workload. It will be interesting to see if the Pi can also handle trunk tracking.
- AceJohnny2 12y agoHow does one handle portable power for a RPi2? Does a normal USB Power brick (as increasingly used to top up phones) suffice?
- wlesieutre 12y agoYup, if it charges a phone it should power a Pi. http://www.adafruit.com/products/1566 http://www.adafruit.com/products/1566 is sold specifically for this purpose, and it has some interesting notes about how it behaves (like output fluctuation when the battery is simultaneously charging and providing power) that might be worth noting. If all you do is run off a battery, then unhook the battery to charge it, you shouldn't have those sorts of issues.
- AceJohnny2 12y agoThose are some very interesting notes, Adafruit excels again. Thanks for the link!
- nearengine 12y ago500mA and up will charge a phone (assuming you're not also doing power-intensive things on it), but you'll probably need 1-2A to power a Pi and a SDR reliably.
- wlesieutre 12y agoAh, looks like power consumption west up. B+ listed 600 mA typ, 2B is 800. http://linuxgizmos.com/raspberry-pi-gets-quad-core-soc-keeps-same-price/ http://linuxgizmos.com/raspberry-pi-gets-quad-core-soc-keeps...
- nearengine 12y agoYep! Plus the tuner card itself can use 200mA or so, and if you want to use any other USB accessories they'll be drawing power as well. I unfortunately have too much experience using "phone chargers" that had enough current to run it 90% of the time, but under hard load would cause enough voltage drop on the 5V rail to reboot the Pi.
- johnchristopher 12y agoNo, a `normal USB Power brick´ doesn't suffice. It has to reliably provide 5 volts and at least 700mA (depending on your Pi model and peripherals). The Pi is more sensible to the voltage than the amperage. See http://elinux.org/RPi_VerifiedPeripherals#Power_adapters http://elinux.org/RPi_VerifiedPeripherals#Power_adapters for reliable information about that. The Raspberry Pi forums are filled with "90% of the time it's the power supply not up to the specs, please check the specs" messages for any power and `random crashes´ related problems.
- famousactress 12y agoGot my Pi 2 recently, and it's awesome how much snappier it runs. I've only used them to spin up game console emulator appliances so far. Would love to hear about projects among the HN crowd. I'd really like to use one for something more interesting!
- canadaj 12y agoI use my 1st gen Pi to monitor the temperature in my BBQ smoker and host a single page web application to display the data over wifi. I haven't touched the project in a while, but with summer quickly approaching I think it's time. I don't think I'll see much improvement using the Pi 2, but hey, it can't hurt to upgragde :)
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- andyjohnson0 12y agoI'm in the early stages of building an application that uses the camera module and OpenCV to recognise gestures and generate audio effects. Kind of head/hand operated synthesizer. Maybe hook-up a video projector and throw-in some video effects too. Secondary objective is to renew my acquaintance with C/C++ after years of mainly using managed languages, and to learn modern language features.
- patrickdavey 12y agoI have a raspberry pi A I think it is, hooked up with the camera taking timelapses every day and automated posting to youtube. Gave me an excuse to play with ember for the frontend too -> http://timelapses.psdavey.com http://timelapses.psdavey.com Current project for the pi2 is hooking it up over a 3G modem for remote monitoring of a study site for a science friend of mind. I want to be able for her to send an SMS and for the PI to send back a picture. All the bits are in place, just need to make it nice!. Love the pi - so much fun!
- jlhonora 12y ago
- bayesianhorse 12y agoAm I the only one who thinks this could work as an early-warning system for drone strikes?
- jaguar86 12y agoYou no longer are :).
- mmagin 12y agoI'm guessing (those kind of) drones don't have mode-S/ADS-B transponders.
- toomuchtodo 12y agoThey do have radio emissions you could triangulate.
- madez 12y agoAre you sure? As far as I know they use satellite links. So I imagine they can avoid sending signals towards earth. I also assume they use frequency hopping in a wide range so it's harder to track.
- bigiain 12y agoI dunno, it's a _long_ way to a satellite, and only a short distance to the ground. Given the space/packaging constraints on a drone I wonder just how directional it's uplink antenna could possibly be. (Although I'd bet the satellite probably has a _very_ high gain antenna on board - which'd turn the tables back in their favour...)
- madez 12y agoMaking a drone hard to detect is a major priority. They'll go great length to ensure it's hard to track. However, it'd be interesting to try it. Sadly there are not many drones where I am currently.
- misuba 12y agoWhat are some of the popular applications for SDR? I can't imagine it's all pirate radio and such.
- jff 12y agoAlmost none of it would be pirate radio, since the most common one (RTL-SDR) is receive-only. You can use it to tune in 2m ham radio repeaters, or listen to broadcast FM, or pick up weather radio transmissions, or track which aircraft are flying overhead, or build a little yagi antenna and hear people talking via ham radio satellite, or possibly listen to police radio depending on what your local cops use
- rickr 12y agoYou shouldn't need a yagi to listen to ham sats (transmit you will). A good external omnidirectional antenna should be fine. In addition to the sats ISS always has at least one ham radio operator. They sometimes man the radio and make contacts with hams. In addition to THAT sometimes they operate SSTV (sending pictures via radio) that you would be able to pick up. Very cool stuff! Here's a good site to see where hamsats are: http://www.amsat.org/ http://www.amsat.org/
- tombot 12y agoWhat fun projects can I do with GNU Radio?
- jfoutz 12y agohttp://gnuradio.org/redmine/projects/gnuradio/wiki/WhatIsGR http://gnuradio.org/redmine/projects/gnuradio/wiki/WhatIsGR
- Animats 12y agoNice. Now the question is how accurately you can timestamp the ADS-B replies. If you can timestamp them to within a few hundred nanoseconds, and have at least three (preferably four) receiving stations networked, you can draw a radar picture of your local airspace.
- timthorn 12y agoI'd like to know, but I'm not sure it is possible with a USB SDR stick. My solution in build is to use a high sample rate stereo soundcard with one channel capturing the audio from an analogue receiver and the second capturing a GPS time sync pulse.
- irfan 12y agoThis is how flightradar24.com and flightaware.com work
- ghost91 12y agoNope, they just decode the content of the ADS-B messages.
- ghost91 12y agoThe problem are the RTL2832U receivers. The sample rate is too low, 500ns resolution with 2MSample/s is not enough. For this reason I cannot recommend using the dvb-t sticks as ads-b receiver (the symbol rate is too high, compare nynquist theorem). Multilateration has already be done for ADS-B on large scale, but with different receivers. There are receivers available[1] with nanosecond accuracy (and gps time synchronization). GPS synchronization isn't needed, by choosing other flight paths to provide basic time synchronization between receivers. [1]: <http://radarcape.com/> http://radarcape.com/>
- bigiain 12y agoThere seems to be "a trick"... http://www.rtl-sdr.com/passive-radar-dual-coherent-channel-rtl-sdr/ http://www.rtl-sdr.com/passive-radar-dual-coherent-channel-r... (That's on my list of "things to experiment with one day...")
- spacemanmatt 12y agoGotta wonder if there are already communities sharing profile information for recognizing various government agency employees/vehicles by SDR.