RF range finder doesn’t need to see to calculate distance

radio_rangefinder

Instructables user [Jones Electric] has been quite busy lately, building a radio-frequency range finder. Built as part of a German youth science competition, he and his partner built a pair of transmitter/receiver modules that can be used to measure distances of up to a mile (~1.5km). Their argument for radio-based rangefinders is that laser rangefinders are obviously limited to line of sight, whereas their range finders are not.

To determine the distance between the two stations, the base station is triggered, which starts a counter and sends a 433 MHz signal to the second station. When the second station receives the signal, it in turn broadcasts an 868 MHz signal, which is received by the base station. The total distance between the points is then calculated based upon the round trip time of the two radio signals.

[Jones Electric] claims that the range finder is relatively accurate, with a deviation of up to 5 meters per measurement, and that the accuracy could be increased by adding a higher frequency crystal to the timing circuit.

We are pretty sure using these two frequencies in the US without a license is not allowed, though we are unsure of the usage laws in Germany, where this was constructed.

TI’s Grace – a new MCU IDE GUI (DNFTT)

TI has recently been fighting to gain traction in the market of low-cost microcontroller development platforms with products such as the MSP430 Value Line Launchpad.  In order to meet the needs of a rapidly growing customer base and appeal to a broader market they have recently released Grace beta Graphical Peripheral Configuration Tool. Grace is a plugin for TI’s own Code-Composer Studio (CCS) IDE that allows users to graphically control many aspecst of MSP430 development and is compatible with all MSP430F2xx/G2xx MCUs.

Utilizing a simple “wizard-like” interface, Grace allows users to quickly and efficiently control peripherals such clocks, timers, OpAmps,  ADCs, GPIOs, comparators, and even more advanced features such as serial communications or the configuration of low-level register settings. Once everything is configured as desired, Grace outputs standard C code that can be debugged and handled as if it were hand-written.

Although Code-Composer Studio is not free, there is a 30-day full-featured trial available as well as other (restricted) free licensing options as well. Since CCS is based on the Eclipse open-source  software development framework, perhaps we will see other similar development tools in the near future. Although not an apples-to-apples comparison, we could imagine that such a tool might provide many novice users with a simple and cost-effective alternative to the Arduino IDE.

The questions then becomes: If a later incarnation were to raise the MSP430 line to “Arduino-killer” status, would it be rejoiced as such or would it simply then become a new target for those die-hard microcontroller purists who love to shout “overkill” on the forums at the slightest provocation? Of course we would love to hear your take in the comments below!

Magic 8 Thing answers all of your burning questions

magic_8_thing

[Pete] was hard at work putting off a repair job for a friend, and wondered how much longer he could possibly procrastinate. With no fellow humans in earshot to which he could propose this question, he thought it would be great if he could ask a Magic 8-ball for an answer. Alas, he doesn’t have a Magic 8-ball, so he would have to build one if he wanted his answer.

Continuing to delay the repair job, he scrounged around his house and dug up an ATmega328 to control the 8-ball and a LCD panel to display the sage-like responses. He wanted the 8-ball to be as authentic in operation as he could, so he had to locate some sort of sensor that would register if the device had been shaken. With no accelerometer at hand, he opted to use a mercury tilt switch that he scavenged from an old thermostat. He wrote some software to display the responses from the original Magic 8-ball when shaken, then he threw the components together in a small plastic case.

As you can see in the video below, his Magic 8-thing works just like the original, sans the dark fluid and icosahedron. If you were wondering, he did finally ask the 8-thing whether he had procrastinated long enough on his initial task – the response: “Yes”

If you’re in the mood for more Magic 8-ball shenanigans, check out these posts!

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POV business card is guaranteed to get you noticed

pov_business_card

Some say that handing out business cards is an antiquated practice due to the ubiquity of smart phones which can be used to trade or record contact information in mere moments. Instructables user [sponges] however, doesn’t agree and is pushing a “business card renaissance” of sorts with his POV business card.

Hand-built in his basement, the cards feature a handful of SMD LEDs that display his name, followed by his phone number when waved back and forth. Constructed to be nearly the same size as a standard business card, his verison uses a PIC to manage the display as well as a tilt sensor to monitor the card’s motion. His walkthrough is quite thorough, and includes tutorials for each of the steps required to build the card. He discusses constructing your own etching tank, converting a laminator for PCB transfer purposes, building a solder reflow oven controller, as well as hacking an aquarium pump for use as a vacuum-powered pick and place.

The end result is a sharp looking business card that ensures you won’t forget meeting him. Keep reading to see a video of the card in action.

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HERF gun zaps more than your dinner

Instructables user [Jimmy Neutron] had an old microwave sitting around and figured he might as well gut it to build a high-energy radio frequency (HERF) gun.

The concept of a HERF gun is not incredibly complex. Much like your microwave at home functions, a high voltage power source is used to drive a magnetron, which produces micro wave radiation at 2.45GHz. These waves are then guided away from the magnetron using a waveguide, towards whatever the target might be. These waves then energize the target in a similar fashion as the water molecules in your food are energized during cooking.

[Jimmy] has not quite finished his HERF gun as he still needs to build a waveguide for it and then safely mount it for use. In the meantime, check out the pair of HERF guns we found in the videos below.

As a parting note, we must stress that building a similar device is dangerous, very dangerous – especially if you do not know what you are doing. Microwaves contain high voltage components, and exposure to microwave radiation can be deadly under certain circumstances. Stay safe!

Looking for more microwave fun? Check these out!

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Clever hack tethers a Kinect sensor to the PS3

kinect_for_ps3

Now that Kinect has been hacked to work with just about everything from robots to toaster ovens, someone finally got around to tweaking it for use on the PS3.

[Shantanu] has been hard at work writing code and experimenting with some preexisting Kinect software to get the sensor to talk to his PS3. The Kinect is hooked up to a PC, which captures all of his movements with OpenNI. Those movements are mapped to PS3 controls via NITE, a piece of middleware used for interpreting gestures into commands. All of the captured button presses are then relayed to the PS3 over a Bluetooth connection using DIYPS3Controller.

As you can see in the video below, the solution works pretty well for what should be considered pre-alpha code. He has been able to map several custom gestures to button presses, and the Kinect does an overall decent job tracking his limbs and translating their movements to on-screen actions. The actual in-game use is a bit rough at the moment, but aside from the infancy of the code, you have to remember that these games were never meant to be played with the Kinect.

It’s a job well done, and we can’t wait to see where this project goes.

Looking for more Kinect fun? Look no further than right here.

[via Kinect-Hacks]

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Freedombot explores your fridge

Freedombot is a neat little robot designed for exploring magnetic surfaces. It has two whiskers for detecting objects in its path and two rare earth magnets which allow it to stick to your fridge.

Overall Freedombot may not be anything revolutionary but its builder [skater_j10] does a good job of covering topics which my be interesting to robotics beginners. For example he goes through the process of modifying some HiTec HS- 55 Micro Servos for continuous rotation which allows them to act as the wheels. To control the bot he uses two 555 timers wired up in astable mode to generate the needed PWM for the servos. The proximity sensors are simple limit switches with some wire soldered on to the end.  The end result is a neat little robot for roaming the front of your fridge. See a video of it in action after the break.

This happens to be [skater_j10]’s entry into the 555 timer contest. Unfortunately the deadline has passed for new entries but be sure to swing by and check out some more awesome 555 hacking.

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