Model Rocket Radio Telemetry

February 17, 2011 by Mike Nathan 8 Comments

rocket_telemetry_data-analysis

[Ken] sent us his Instructable in which he used radio telemetry to monitor the status of his air-powered model rocket through a series of launches. His setup is centered around an Arduino IDE-compatible board that looks to be about the size of a Boarduino, but has the benefit of an embedded 915 MHz radio module. The vendor he used also sells a good handful of add-on modules which he used for his in-flight recording, including a barometric pressure monitor and a 3-axis accelerometer. During flight, the rocket constantly sends data to a base station, provided it stays within radio operating range.

For is initial tests, [Ken] launched his rocket four times, getting usable data on half of them. He found out some interesting things about his model rocket, including the fact that it creates a maximum launch force of 60 Gs. He has plans to revise his setup in the future, such as lightening the battery load as well as adding a high-G analog sensor for recording the forces at take off. This kit, or a more reasonably priced clone, would make for a great addition to any rocket buff’s inventory.

Wireless Sniffing And Jamming Of Chronos And Iclicker

January 25, 2011 by Joseph Thibodeau 1 Comment

The ubiquitous presence of wireless devices combined with easy access to powerful RF development platforms makes the everyday world around us a wireless hacker’s playground. Yesterday [Travis Goodspeed] posted an article showing how goodfet.cc can be used to sniff wireless traffic and also to jam a given frequency. We’ve previously covered the work of [Travis] in pulling raw data from the IM-ME spectrum analyzer, which also uses goodfet.cc.

The Texas Instruments Chronos watch dev platform contains a C1110 chip, which among other things can provide accelerometer data from the watch to an interested sniffer. The i>clicker classroom response device (which houses a XE1203F chip) is also wide open to this, yielding juicy info about your classmates’ voting behaviour. There is still some work to be done to improve goodfet.cc, and [Travis] pays in beer–not in advance, mind you.

With products like the Chronos representing a move towards personal-area wireless networks, this sort of security hole might eventually have implications to individual privacy of, for example, biometric data–although how that might be exploited is another topic. Related to this idea is that of sniffable RFID card data. How does the increasing adoption of short-range wireless technologies affects us, both for good and bad? We invite you to share your ideas in the comments.

Radios Without Power Sources

January 25, 2011 by Mike Szczys 37 Comments

[Goodhart] is sharing his process for building a couple different AM radios. It’s surprising how few components he’s using; the first build is just a germanium diode, some wire, and a piezo earpiece. But it strikes us that both of the radios he gives build instructions for have no power source. We’re also amused by the process of selecting the station. His example uses 770 AM, and requires you to take the wire and place it up in a tree with the two ends about 1216 feet apart. We think there’s something a bit off with the math, but with that much conductor to start with there might be enough induced current for you to actually hear something come out the piezo. We don’t think we’ll be trying this anytime soon, but we’d like to hear comments from those of you who do (or already have).

Vintage Car Audio Gets MP3 Input

December 8, 2010 by Mike Szczys 20 Comments

[Nali] is fixing up a 1966 Rambler Ambassador and decided to give the audio a bit of an upgrade. Instead of replacing the head unit he added a connector for audio input. The method he used is simple, inexpensive, and allows the original unit to continue functioning as a radio. He cut the feed wires going to the volume knob and patched in a headphone jack. The jack he used has an internal switch that is meant to switch off a pair of speakers when headphones are plugged in. The jack will allow the original signal from the radio tuner to pass through whenever there isn’t a connector plugged in. It seems like this is easier on older hardware than it is on modern equipment.

This isn’t where his entertainment enhancements stop. [Nali’s] working on a 7″ in-dash Linux machine so keep your eye on his thread to see what he comes up with.

[Thanks Joel383]

Step By Step Antique Radio Repair And Upgrade

November 6, 2010 by Caleb Kraft 20 Comments

I actually have a 3 very similar radios. I think I need to do this. [M3talhead] takes us through a very informative repair of an old tube radio. In this case, his radio was from the late 30s. He was able to find the original data from Radiomuseum.org. He painstakingly dismantles the radio components and the cabinet. Instead of completely modernizing the internals, he replaces the bad parts and brings it back to functionality. He wanted to do an MP3 upgrade, but rather than wire directly into the radio, he built an AM transmitter for his mp3 player.

Plantenna: The Plant Antenna

October 20, 2010 by Jakob Griffith 37 Comments

The back story behind [Mike] experimenting with plants as AM radio transmission antennas antennae is rather interesting and worth the short read. But for those who just want the facts, [Mike] took an ATMega324, modified the PWM output into a sinusoidal AM signal (using a simple form of RLC circuitry), and connected the circuit to a plant no plants were harmed in the making of this project. The results? Well we’re not ones who would spoil the surprise, you’ll have to see for yourself in the video after the jump.

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Building A Crystal Oven

September 28, 2010 by Mike Szczys 13 Comments

Radio communications depend on stable oscillator frequencies and with that in mind, [Scott Harden] built a module to regulate temperature of a crystal oscillator. The process is outlined in the video after the break but it goes something like this: A small square of double-sided copper-clad board is used as a base. The body of the crystal oscillator is mounted on one side of this base. On the other side there is a mosfet and a thermister. The resistance of the thermister turns the mosfet on and off in an attempt to maintain a steady temperature.

This is the first iteration of [Scott’s] crystal oven. It’s being designed for use outdoors, as his indoor setup uses a styrofoam box to insulate the oscillator from ambient temperatures. He’s already working on a second version, and mentioned the incorporation of a Wheatstone bridge but we’ll have to wait to get more details.

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