Digital Marker Communicates With Touch Screen

October 13, 2012 by 27 Comments

In an effort to be more relevant to children that just aren’t impressed with crayons and markers anymore, Crayola released the ColorStudio HD pen. Instead of ink, this pen is filled with electronics that communicate with a tablet to draw different colors in the Crayola ColorStudio app.

[Rob Hemsley] had done some work with capacitive touch screens before, so when he heard the clicking of a tiny relay inside the pen, he automatically knew how it worked. Of course this meant tearing apart the Crayola marker to look at the electronics, but [Rob] also went so far as to replace the microcontroller, allowing you to craft your own ColorStudio HD pen.

The digital Crayola marker communicates with the app by switching a relay on and off very quickly. This completes a circuit between the user’s hand and the touch screen, allowing the tablet to interpret the desired color by measuring how many touches are received per second.

Inside the pen, [Rob] found an RGB LED, a relay, and a PIC microcontroller. Not having any experience with PICs, [Rob] changed out the ‘micro to an ATtiny44 and started writing some firmware with the help of the Arduino IDE.

[Rob]’s updated version functions exactly like the stock version, communicating with the Crayola app by pulsing the relay to indicate the selected color. Even though the Crayola app only has three possible colors, [Rob] says it’s feasible to program the digital pen to send an RGB color value to a tablet, allowing you to choose what color to draw with on the pen.

You can see a video of [Rob]’s updated pen after the break.

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Knock Lock Balks Knock, Uses CapSense Without Shock

August 6, 2012 by 42 Comments

[Rob Hemsley] sent in an update to an RFID-based door lock. Previously, if you wanted to enter the MIT media lab, a RFID-enabled card was required to get in. Now, with [Rob]’s update, you only need to tap the door handle in a ‘secret’ pattern.

The earlier RFID-enabled build used about $80 in hardware, not a very economical solution. The new touch-based solution only uses an Arduino and servo, making the build much cheaper.

The touch sensitive lock uses the CapSense Arduino library. By turning the door handle into a touch sensor, [Rob] allowed a secret code to be saved in the EEPROM. Repeating this sequence when the door is locked sends power to the servo, unlocking the door.

A very cool build that’s also a little more secure than the traditional, audible knock lock. Check out the video after the break.

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Shaper Tools Will Blow Your Mind

May 20, 2016 by 73 Comments

Have you ever wanted to own a full-sized ShopBot? What if some geniuses somewhere made a tool the size of a coffee maker that had the same capabilities? Does an augmented reality, real-time feedback, interactive, handheld CNC router that can make objects ranging in size from a pillbox to an entire conference room table sound like a thing that even exists? It didn’t to me at first, but then I visited the Shaper Tools office in San Francisco and they blew my mind with their flagship tool, Shaper Origin.

This table and the spool holder sitting on it was made with a machine the size of a coffee maker.
This table and the spool holder sitting on it was made with a machine the size of a coffee maker.

It’s impossible for me not to sound like a fan boy. Using Shaper Origin was one of those experiences where you just don’t know what to say afterwards. This is what the future looks like.

I’ve used a lot of CNC tools in my life, from my first home-built CNC conversion, to 1980s monstrosities that ran off the floppy kind of floppy disks, and all the way over to brand new state-of-the-art vertical machining centers. I had to shake a lot of that knowledge off when they demoed the device to me.

Origin is a CNC router built into the form factor of a normal wood router. The router knows where it is on the work piece. You tell it where on the piece you would like to cut out a shape, drill a hole, or make a pocket. It tells you where to go, but as you move it keeps the cutting bit precisely on the path with its three axes of control.

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