gps hacks

205 Articles

Speech Recognition Geocache: Se Habla Español

March 18, 2011 by 8 Comments

Instructables user [jorgegunn] has put a unique spin on a recent geocache build by incorporating speech recognition and requiring that the “finder” knows the secret password to access the loot contained within. Although we won’t spoil the fun here, the techie spirit of the build was further bolstered by choosing a password fitting for any trekkie.

Despite utilizing an off-the-shelf speech recognition circuit kit, the majority of this hack was accomplished using parts available at local electronics and hardware stores. [jorgegunn] went to great lengths to make this hack accessible to any amateur hobbyist  and even includes links to relevant tutorials, schematics, and online parts vendors where applicable.

The actual speech recognition is accomplished with an Images Scientific Instruments model SR-06 circuit kit, capable of recognizing up to 40 different predefined words across multiple languages. Any time a correct match occurs, a value corresponding to the memory slot for that word is displayed on a pair of 7-segment displays. A separate decoder circuit based on a 74LS373 D-Type Latch and 4028 IC Decoder CMOS determines if the value being displayed constitutes a valid response and then drives a solenoid via a Darlington transistor in order to release the latching mechanism. Once opened, the device is simply pushed closed again to await its next finder- we are guessing that finding it might actually be the easiest part as judged by its size!

Although the real-world battery life has not yet been determined, a single coin cell for memory retention and a 9V battery used to drive the circuit and for latch release lasted through a full month of testing without any issues. Battery life could be extended almost indefinitely with a simple solar cell and rechargeable battery setup, but this would also obviously increase the likelihood of vandalism and/or theft.

We can imagine many different applications for such a device as-is including automated door lock  mechanisms and even access control to things such as the controls on a computer case.  It should also be fairly easy to increase the security by stringing multiple words together into a password or by instituting a “time out” period after a certain number of incorrect guesses.

Let us know of any other applications or build variations in the comments below and make sure to see how it all came together in the short videos after the break.

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Blasting Off With GPS

February 20, 2011 by 23 Comments

Launching model rockets is a good time, but more often than not, it’s hard to tell how high the rocket went or how fast it moved – both essential facts when bragging about your latest flight. [Chris] recently built a GPS-based altimeter for the USC Rocket Propulsion Lab, so that they could track the performance of their latest project. The circuit is based off a Picaxe 18x and uses a GPS module to obtain NMEA altitude data. Once the data is obtained, it is stored on an external EEPROM to be read back after the rocket has been recovered.

[Chris] unfortunately does not have any pictures of the board he built, but he has made his circuit diagram and source code available. He reports that the logger worked perfectly aside from a small bit of time where the GPS module temporarily lost its satellite lock.

If you are interested in reading more about flight data recording and telemetry, be sure to check this out.

Motion Tracking Prop From Alien Movie

February 17, 2011 by 24 Comments

[Erv Plecter] likes to recreate movie props that actually work. This time around he’s making the motion detector device from the original Alien movie. You’ll immediately remember this prop after seeing and hearing it in the video after the break. For our money, the most brilliant part of that movie was the use of rhythmic sounds to boost the intensity of the tension in the viewer. [Erv’s] build captures that feeling, with the steady beat of sonar and the rising pitch of a ping as an object moves towards you. The device can easily track your own movement, as it contains both a GPS module and an electronic compass. He mentions that there is a motion sensor as well, but is a bit vague about how that part of the build works. Still, it’s a nice little piece which looks great despite not being quite finished yet.

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Black Rock City Navigator

February 16, 2011 by 4 Comments

Only a little bit out of season but better late than never! [Scott] brings us his Black Rock City Navigator. This unique bike mounted GPS device made for Burning Man 2010 features a servo driven array of LEDs. Two LED strips are used to cover the full 240 degrees of the C shaped city without modifying the servo, and are rotated over the different compass points.

It is powered by a pair of Freescale MC9S08AW32 micro controllers, and a unnamed GPS receiver. One controller deals with the servo and GPS data, the second simply drives the LEDs, and why not if you have plenty?

Housing the device is a four inch black sewer pipe end cap with a ball clamp attached, and is toped off with green acrylic engraved with the map of Black Rock City. Add some stickers (because stickers make everything better) and you have a functional device with a top-notch look for this year’s event.

Location Recorder And Mapper

February 3, 2011 by 19 Comments

[Jeroen’s] student project is a module that uses GPS tracking to create travel data on Google maps. It’s not really a spy device as the data isn’t transmitted, but would be a lot of fun to use on cycling and hiking adventures. A PIC 18F2550 reads location and altitude data from a GPS receiver as well as data from an accelerometer. This information can be displayed on an attached touchscreen display and it is also saved to a pair of EEPROMs. When you get back from your trip, the data pulled from the device via a serial connection is processed by [Jeroen’s] C# application and used to overlay the route on a google map. He’s got a source code package available for download but we’ve saved you the trouble if the schematic is all you’re after. It’s attached after the break.

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Reverse Geocache Features UI And Is Reprogrammable

January 9, 2011 by 7 Comments
Here is yet another offering in the Reverse Geocache puzzle arena. We’ve been getting a lot of tips about these projects but this one in particular stuck out from the others. [Mure] packed in a bunch of features, starting with the LCD screen seen above. You can just make out the single red button near the bottom of the image which is used to traverse the menu. The octagonal box has an octagonal PCB inside that includes a USB connector. As you can see in the video after the break, this can be used for charging the batteries, and communicating with the internals. An accompanying program is used to generate puzzle data, which can then be programmed via that USB connection to set a new puzzle location. This functionality certainly protects against accidental lock-outs which were a problem with the last puzzle we looked in on.

Reverse Geocaching Christmas Gift Box

January 2, 2011 by 12 Comments

This is the reverse geocache box that [William Dillon] built as a Christmas gift this year. He started with an interestingly shaped wooden box from the craft store. The clasp to keep it shut uses a servo motor on the lid with a wooden arm that grasps a screw on the base. As with the original geocache box, the Frustratomatic, and the smaller geocache, the box is designed to open only when in the correct geographic location thanks to the GPS module inside. That was a problem for [William] when a bug in his firmware locked the box during development while the key location was 1000 miles away. Luckily the box uses hinges that are attached from the outside with screws. We wonder how feasible it would be to use the mounting screws from the LCD screen to implement a coded emergency entry, using one as ground and the others as paths to microcontroller pins.