Comments on: AVR RFID tag

By: luke

luke — Wed, 25 Jan 2012 18:35:10 +0000

Lol who even needs a size reference if there’s a dip-8 in a pic???

By: Ken

Ken — Tue, 27 Sep 2011 02:16:06 +0000

New Link to this HACK

By: David M.

David M. — Thu, 16 Jun 2011 15:23:01 +0000

I’m having trouble compiling the code for an ATMega168 target, using the HID mode. For some reason, the lines:

manchester HID_SITE_CODE, 8
manchester HID_UNIQUE_ID, 16

have to be commented out, or else the compiler blows up with this error, like the chip is out of memory (the program code is 7496 bytes when compiled for attiny85).

avr-gcc -Wl,-Map,avrrfid.map -mmcu=atmega168 -o”avrrfid.elf” ./avrfid.o
./avrfid.o: In function `loop’:
(.text+0x1d12): relocation truncated to fit: R_AVR_13_PCREL against `no symbol’

By: SparkyGSX

SparkyGSX — Mon, 19 Apr 2010 06:56:12 +0000

It’s not entirely original, at least not the way the chip is powered. I saw something similar, years ago, called iglassware (see website link for PDF).

One problem with using the I/O pins for power on an AVR is that the ESD diodes are very weak, and could fail in this application. PIC devices have much better ESD diodes (I think Microchip specifies 10 or 20mA, while Atmel specifies “<1mA" and "do not use").

By: therian

therian — Mon, 29 Jun 2009 23:13:51 +0000

timour patent on diode or 1wire ? lol

By: bluesman

bluesman — Mon, 29 Jun 2009 22:24:46 +0000

Minimalistic, awesome, pure creativity, just brilliant. You must be very proud of this kind of beautiful ideas!! My most sincere Congratulations.

By: timour

timour — Mon, 29 Jun 2009 15:51:01 +0000

so we could have cpu with only 2 pins, like a resistor in a 0805 package

By: timour

timour — Mon, 29 Jun 2009 15:46:40 +0000

therian, i mean a patent for the supply without a dedicated supply pin.

By: Tachikoma

Tachikoma — Mon, 29 Jun 2009 14:08:12 +0000

Yeah!

They should use Chinese Yuan for a change!

Or something.

By: Wwhat

Wwhat — Mon, 29 Jun 2009 13:56:37 +0000

Fuck all people who use US quarters for size comparison, hope they die in a fire already, I’m sick and tired of it as you might have surmised at this point.

By: t

Mon, 29 Jun 2009 12:49:48 +0000

simply ingenous!

By: therian

therian — Sun, 28 Jun 2009 19:50:41 +0000

timour patents cost a lot of money. This idea is very good but special rfid chips cost much less

By: timour

timour — Sun, 28 Jun 2009 19:02:57 +0000

5 stars hack
i did also notice the power by the i/o, but always see it as a drawback.
genuine genius, you shoud request a patent for that

Hack a Day, more like this please

By: Hackius

Hackius — Sun, 28 Jun 2009 09:53:19 +0000

If you power the AVR then you can brute force a RFID reader. If I had a AVR programer I’d try it.

By: conundrum

conundrum — Sun, 28 Jun 2009 08:44:23 +0000

interesting…
could also be handy for powering “smart” tags that can log environmental data using ambient light, and then be read back wirelessly.