Rocket Acceleration Logger

rocketdatalogger

Have you ever wondered how high or how fast a model rocket goes when you launch it? [sprite_tm] did, so he decided to build a low cost, lightweight data logger that he could fit into the nose cone of his rocket. To keep the circuit small, he built it around the popular ATtiny13 microcontroller. The microcontroller collects data from a Freescale MMA7260, a 3-axis accelerometer that he extracted from a third-party Wii nunchuck controller. After the microcontroller collects the data, it’s stored in 32K of EEPROM on a 24C256. All of this is powered by a small 3.6v Li-ion battery, which is the largest part of the circuit. If this sounds like something you’d like to make, he has detailed instructions along with the software used available on his site. While we don’t launch a lot of model rockets here, we may soon start just so that we have an excuse to build this.

Autonomous ATV

[youtube=http://www.youtube.com/watch?v=Ja3ND8Pk_0M&hl=en&fs=1]

A team at UNC Charlotte has been working on an autonomous vehicle to drag a cart that has sensing equipment. Starting with a stock Honda ATV, different systems were added to give a Renesas processor control of the ATV.  A model airplane receiver was attached to the Renesas to give remote control for Phase 1 of the project. Basically they’ve turned the ATV into a giant remote controlled car.

Later revisions will incorporate LIDAR, cameras, and multiple GPS units so the ATV can autonomously traverse most terrain with a high level of accuracy. Path planning will become a large part of the project at that point.

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GPS Cradle Upgrade To Bluetooth

ipaq_gps

[emuboy] sent in this neat hack where he converted a GPS dock to bluetooth (google translated). He has an ipaq rz1710 and a Kirrio GPS cradle. Apparently there were annoying problems when inserting the ipaq into the cradle. He decided that he would much rather just connect via Bluetooth. After tearing apart the cradle, he found the documentation for the GPS chip online. He ordered a bluesmirf bluetooth modem and got to work. The end result is something that could be concealed in his car and just connected to when he gets close enough.

Segway And Input Filtering

seg

[Kerry] is building a segway type vehicle for a senior project. Though it doesn’t appear to be done yet, there is some good work finished. As with any balancing bot, it relies heavily on input from a gyroscope, and at least in this case, an accelerometer. That data can be very messy. The sensitivity of the sensor means that people often end up with vibrating or drifting in their projects. [Kerry] has put some work into finding a method of smoothing that results in fast, accurate, but smooth reaction. You can see a video of some comparisons between methods after the break.

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Desulfator In An Altoids Tin

desulfator

If you’ve ever let a car sit for a period of time and returned to find that the battery was mysteriously “dead”, you were probably experiencing a sulfate crystal build up. Often, people just buy a new battery and plop it in, but that isn’t absolutely necessary. [Kmpres] takes us through the process of building a desulfator. A desulfator works by putting high voltage pulses into the battery forcing the sulfate crystals to dissolve back into the electrolyte. From what [Kmpres] says, you can find “bad” batteries in all kinds of places, use the desulfator on them and have perfectly fine batteries when you’re done. You may recall doing something similar with a disposable camera.

OpenVulture, Software For Unmanned Vehicles

barbie

The first talk of ShmooCon was [Ethan O’Toole] and [Matt Davis] presenting their OpenVulture software for unmanned vehicles. In the initial stages, they had just planned on building software for Unmanned Aerial Vehicles, but realized that with the proper planning it could be used with any vehicle: airplanes, cars, boats, and subs (or more specifically, their Barbie PowerWheels). The software is in two parts. First is a library that lets you communicate with each of the vehicle’s modules. The second half is the actual navigation software.

They’ve spent a lot of time sourcing hardware modules. They are looking for items that work well, aren’t too expensive, and have a fairly plug and play implementation. For their main processor, they wanted something that wasn’t a microcontroller and could run a full Linux system. The ARM based NSLU2 NAS seems to be the current frontrunner. You can find the opensource software and descriptions of the supported modules on their site.

They’re building the first test UAVs now. One has a 12 foot wingspan for greater lift and stability. We’ve covered the Arduino based Ardupilot and other UAVs in the past.

Mobile RFID Scanning

[youtube=http://www.youtube.com/watch?v=9isKnDiJNPk]

[Chris Paget] is going to be presenting at ShmooCon 2009 in Washington D.C. this week. He gave a preview of his RFID talk to The Register. The video above demos reading and logging unique IDs of random tags and Passport Cards while cruising around San Francisco. He’s using a Symbol XR400 RFID reader and a Motorola AN400 patch antenna mounted inside of his car. This is industrial gear usually used to track the movement of packages or livestock. It’s a generation newer than what Flexilis used to set their distance reading records in 2005.

The unique ID number on Passport Cards doesn’t divulge the owners private details, but it’s still unique to them. It can be used to track the owner and when combined with other details, like their RFID credit card, a profile of that person can be built. This is why the ACLU opposes Passport Cards in their current form. The US does provide a shielding sleeve for the card… of course it’s mailed to you with the card placed outside of the sleeve.

Technology exists to generate a random ID every time an RFID card is being read. The RFIDIOt tools were recently updated for RANDOM_UID support.

[Thanks Zort]