• scanlime:012 / Graphics Tablet Primer for Hackers

    This time we’re hurtling through the layers of technology that make a graphics tablet (pen tablet) work, from operating systems politics to electromagnetic induction. I’ll be looking closely at two tablets, the Wacom Intuos Pro and Huion H610PRO, and going into a full teardown on the Huion.

  • AVR RFID, Optimized and Ported to C

    AVR RFID, Optimized and Ported to C

    Way back in 2008, I posted a writeup about using an AVR microcontroller as an RFID tag. Since then, it’s been great to see many people pick up this code and build their own DIY RFID tags. In my original project, I was just interested in using an AVR as a way of emulating any…

  • Duct tape RFID tag #1

    Duct tape RFID tag #1

    This is just a messy first prototype, but I recently tried making an AVRFID tag on a substrate of duct tape. The first attempt involved: An upside-down strip of duct tape, as the base for everything else to stick atop 100 turns of AWG 40 magnet wire around a ~66mm diameter form, which I then…

  • AVRFID 1.1 Firmware

    AVRFID 1.1 Firmware

    I don’t normally write bloggy posts on every version of every source file I check in, but every so often an older project sees some more activity, and I love the opportunity to revisit software I wrote years ago. Sometimes I wonder why I wrote such-and-such thing that way and oh my god what an…

  • Soft RFID tags and cuddly plushies

    Soft RFID tags and cuddly plushies

    This week a new power tool arrived on my desk: How did this happen? It was actually kind of complicated… Months ago, Scott and I dreamed of an automated kegerator. For the workplace, naturally. We’d need some way to hand out credits that coworkers could use in order to dispense beer, so we’d need a…

  • Using an AVR as an RFID tag

    Using an AVR as an RFID tag

    Experiments in RFID, continued… Last time, I posted an ultra-simple “from scratch” RFID reader, which uses no application-specific components: just a Propeller microcontroller and a few passive components. This time, I tried the opposite: building an RFID tag using no application-specific parts. Well, my solution is full of dirty tricks, but the results aren’t half…

  • RFID Garage Door Opener

    RFID Garage Door Opener

    Today I finished a major update to my software-only RFID decoder for the Propeller microcontroller, and I finally installed my prototype in the garage. Now I can open the garage door with my RFID badge from work, while I’m on foot or on my bike 🙂 I’ll post some pictures once there’s some sunlight.

  • Simplest RFID reader?

    Simplest RFID reader?

    That’s a Propeller microcontroller board with a few resistors and capacitors on it. Just add a coil of wire, and you have an RFID reader. Here’s a picture of it scanning my corporate ID badge, and displaying the badge’s 512 bits of content on a portable TV screen: If you’re into that sort of thing,…