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1  Forum 2005-2010 (read only) / Interfacing / Re: Coding Question: Making a ShiftIn on: March 13, 2007, 01:33:18 pm
Hmm.. Isn't the Clock an input too?  :-/
2  Forum 2005-2010 (read only) / Interfacing / Coding Question: Making a ShiftIn on: March 11, 2007, 10:42:26 pm
Hey folks.

How would I go about coding something like a"ShiftIn" function? I have a "clock in" and a "data in", and I want to print the results to the serial port.

Thanks in advance!  ;D
3  Forum 2005-2010 (read only) / Interfacing / Re: Mifare 500B RFID Reader on: July 18, 2008, 07:26:08 pm

Here's an article I posted about this neat little board.. Maybe something in here (including the link I included to the Fudan Microelectronics FM1702NL datasheet) will help?

I noticed that the FM Chip is part of a series, with other options including more protocols... I wonder if they're swappable?  :smiley

Anyways, here's my writeup, so far, on this little guy.

I just dug out my Arduino, so I'll have to try connecting the two. I'm guessing it'll be by UART.
4  Forum 2005-2010 (read only) / Interfacing / Re: Mifare 500B RFID Reader on: October 26, 2007, 06:53:19 pm
Where did you get it? I've been looking for something that could handle multiple simultaneous reads (anticollision)  I'd be REALLY interested in your progress. Please keep me posted.

I got it from eBay, from It came with a credit-card-sized plastic card, not sticker-card like it says in the auction, but I'd rather have a plastic one, personally  8-)

Look for "13.56Mhz RFID Reader module with C source&Doc & Antenna" under the "RFID" section. The website, which is in SERIOUS need of an upgrade, is I'll be posting relevant stuff on my website later on. I'll post again when I do.

Search up the "Philips Mifare MF RC500" IC datasheet, the reader uses either that or a clone.
Also, see and for an overview of the technology used.
5  Forum 2005-2010 (read only) / Interfacing / Re: Mifare 500B RFID Reader on: October 26, 2007, 12:17:41 am

I just got one too!  ;D Funny how those things seem to happen. Anyways, I'll try, and see what happens  smiley-wink
6  Forum 2005-2010 (read only) / Interfacing / Digital Input Question on: August 27, 2006, 11:22:23 pm
Hey all. I've got a barcode reader that gives:

"A series of pulses with widths proportional to the widths of the bar code elements being scanned. A low output represents a bar, and a high output represents a space. The frequency of the pulses depends on the density of the symbol being scanned."
--LT 1800 Product Reference Guide

How would I read this? I've tried reading it as serial, but I don't think that's how it was meant to be done. Right now i'm toying with pulseIn HIGH and LOW, but I have a feeling that:
 duration1 = pulseIn(barCode, HIGH);
  duration2 = pulseIn(barCode, LOW);
misses a whole LOW, HIGH series in between, based on its description. If the first pulseIn waits for a HIGH, then counts until it hits a LOW, the next pulseIn wouldn't start on that LOW, it would start on the next LOW, right?

I mean, with that in my loop, I get about half the number of HIGH/LOW that I should for a barcode.

How *should* I do this? Is the PWM feature on the output only, or is there some kind of PWM input functionset?
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