PIC-based voice recorder

PIC-based voice recorder:

[Vinod] just finished building a voice recorder and it turned out even better than he thought it would. The video after the break shows him recording what is surely one of your favorite songs from his cellphone and then playing it back. The audio quality does sound quite good for a project with very few components.

A PIC 16F877A makes up the majority of the build. Its ADC is used to capture the incoming line from an amplified microphone input (you’ll find that amp schematic half way through his post). He’s storing the data on an MMC card, which was a bit of a hack since the PIC has limited RAM to manage that overhead. The stored data is in a raw format, as the card is not accessed using a file system. This makes it easy to record at a high bit rate, leading to better audio quality. Playback consists of connecting a speaker via a low-pass filter and amplifier circuit to the hardware PWM output on the PIC.

Filed under: digital audio hacks

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Video – Eagle CAD’s CAM processor

Video – Eagle CAD’s CAM processor:

Here is the next installment in our series of Eagle CAD videos. In this video we skip ahead a bit and show off the CAM processor that you use to create the files necessary to have your circuit boards be manufactured. After watching this video, you will know how create a new CAM program, load a circuit board into the CAM processor, tell it where to save your files, and actually use it to create the files.

We’re skipping ahead today because of a screw up on our part. We meant to show the layout portion of the program today but edited the wrong video… We’ll show layout next week. After that, we will show the completed circuit board and solder the parts onto it.

If you are itching for some Eagle CAD layout info, you may be interested in some supplementary videos that we have uploaded to our Youtube channel. In those videos, we show how to use the most important features in the layout portion of the Eagle CAD.

Have you missed the previous videos? Here are some links to them:

Schematic and the beginning of a custom part: [click here]

More custom part stuff: [click here]

Video is after the break:

Filed under: news, video hacks

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Video: Eagle CAD Layout

Video: Eagle CAD Layout:

This week’s video is the last in a series of videos where we show how to use Eagle CAD. Today we will look a the Layout portion of the program and will create a circuit board from the schematic that we created previously. We start by creating a layout file and then moving all of the parts to appropriate places on the circuit board. After that, [Jack] shows how to route the traces. Along the way, he talks about the tools that he is using and various ways to use them. The end result is a prototyping board for the PIC18F44J11.

Like the others, this video is fairly long at 29 minutes, so make sure to have some time dedicated towards watching it if you do.

In next week’s video, we will be showing this board as it arrived to us from a manufacturer and will do a tutorial on how to solder.

If you have missed our previous videos, you can find them here:

Schematic part I

Schematic and Custom part creation

CAM Processor

We have also created many supplemental videos explaining how to use many of the tools in the tool palettes. You can find them on our Youtube channel:

Check out the video after the break!

Filed under: news, video hacks

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RF sniffing on-the-go

RF sniffing on-the-go:

It’s been a while since we checked in on [Travis Goodspeed]. His latest post makes RF sniffing with the Next HOPE badge more portable by ditching the need to display data on a computer. He’s built on the work he did at the beginning of the year, replacing the FTDI chip on the badge with a Bluetooth module. Now he can use his Nokia N900 as a GoodFET terminal to not only display the packets pulled from the air, but the control the badge as well.

Previously, the client running on the computer was communicating with the badge via a serial connection. To get it working on the N900 [Travis] transitioned from using py-serial over to using py-bluez. All of the code changes are available from the GoodFET repository.

He’s got a few other tricks planned for this concept. He put in a parts order to add Bluetooth to the Girltech IM-ME. The pretty pink pager has the same radio chip on board, so adding Bluetooth connectivity will allow it to be used in the same way. There are also plans in the works to add a couple other packet sniffing protocols to the bag of tricks, including ZigBee.

Filed under: security hacks, wireless hacks

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A laser cutter challenge

A laser cutter challenge:

When the Louisville hackerspace LVL1 was discussing the purchase of a new laser cutter, a member said, “I could build one before you get around to buying one.” The gauntlet was thrown down, a challenge was set, and the race was on to build a tiny laser cutter before the hackerspace took delivery of their new laser cutter.

The mechanical aspect of the build is fairly simple. The X axis is simply a stepper motor, threaded rod and laser module mounted on a carriage. This carriage moves along the Y axis with the help of two stepper motors for either side. Everything was mounted on more perfboard than reason would suggest.

For the electronics of the project, three motor drivers were made with a few logic chips and the laser firing relay was stolen from test equipment developed for LVL1′s trans-Atlantic balloon build. Motor and laser control was handled by an Arduino to keep the build simple because the contest was over after the first laser was finished cutting a square.

LVL1 is now working on a second version of the winner of the laser cutter challenge. They’re planning on a touchscreen interface that will cut a plastic blank about the size of a credit card. We can’t wait to see the results of that build.

Filed under: arduino hacks, cnc hacks, laser hacks

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