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NerdKits Newsletter Archives » NerdKits Newsletter #18 - Talking Digital Calipers & Huffman-Coded Audio

November 07, 2011
by mrobbins
(NerdKits Staff)

mrobbins's Avatar

This newsletter was released on November 7th, 2011.

Hi! This is the eighteenth edition of the NerdKits Newsletter, which we publish to keep you and the world up to date with everything going on at NerdKits.

  1. Halloween Hijinks: Huffman-Coded Audio
  2. Talking Digital Calipers for Engineering Accessibility
  3. Give a NerdKit this Holiday Season -- Special Promotion
  4. Schematics & Simulation Survey -- win a $50 Amazon gift card!


For our Halloween project this year we decided to do a nerdy take on a classic prank: scaring trick-or-treaters. This project uses a magnetic reed switch, a NerdKit, and set of computer speakers to frighten unsuspecting visitors at the door.

In covering this project, we get a chance to go over some pretty neat engineering concepts. In the video we go over the concept of digital audio, and how we compressed the data using using Huffman codes. We also cover audio playback via PWM with analog filtering.

As usual, you can find the video and a full explanation of the concepts behind this project, as well as schematics and source code, at the project page:


Last year, we released our Digital Calipers DRO video tutorial. It showed how we used a NerdKit to read the current measurement from a set of digital calipers. The setup was then mounted on our Lathe-Mill machine to give us a continuous digital readout, which was much easier to work with than the mechanical dials on the machine. A few months after we published that video we received an e-mail asking if it would be possible to adapt this project to make talking calipers that would read the value out loud over a set of speakers for a blind mechanical engineering student to use.

Reading the data in the same way that we did for our DRO project, and combining that with the same audio storage and playback technique we used in our Halloween Huffman-Coded Audio project (see above), we were able to make the talking calipers that read the current measurement out loud.

The video for this project contains a segment where Terry explains how he uses the talking calipers in his job and engineering classes, so make sure you check it out! Check out the project page:


Just like last year, we want help encourage our current customers to give the gift of learning, and help us bring electronics and microcontrollers to as many people as possible. For the holiday season (now through December 31st), we are giving you an incentive of $20 store credit for every additional NerdKit you buy as a gift through the end of 2010. After your purchase is complete, a NerdKits store credit of $20 will be automatically added to your account, so you can pick up extra parts to further your own projects.

For more information about our store credit system, please visit your store credit page at:

If you want to take advantage of this holiday season offer, make sure you are logged into your user account on our website, then head over to our store:

to pick up the NerdKits.

(Note: in the spirit of the "give as a gift" promotion, only current customers are eligible to receive this store credit.)


We're curious about how electronics hobbyists, students, and professionals use schematics and circuit simulation as they learn, work, and play. Can you spare a few minutes to take a brief one-page survey about how you use schematics and simulation?

NerdKits customers who participate by Friday will be entered to win a $50 gift card.

(Survey submission must be completed by 11/11/11 at 11:11:11PM PST. Must provide NerdKits username. Limit one entry per username. One winner from the valid submissions will be selected at random to receive an $50 gift card to, transmitted electronically. Contest void where prohibited.)


Thank you for taking the time to read this, and for being such great customers. Make sure you tell your friends and neighbors about NerdKits so we can keep the world's DIY spirit alive!

Best wishes,

Humberto & Mike
NerdKits, L.L.C.

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