Preparing a RFID board

To make the assignment for the ATTINY44 more fun, I am racing to get another board working with a RFID reading chip.

I have done experiments with the Phidget RFID reader, which works perfect of course but is expensive, around 50 euro’s.

Then I found the at http://www.pollin.de a rfid kit of 15 euro’s, which I built and tested. I made the coil winding myself it was very sensitive, one more or less made a big difference in response.

The circuit was based on the ATMEL datasheet of the U2270B.

So I realized much of the board was not needed, buying this chip for 3 euro’s at http://www.pollin.de. But the capacitators needed are not so current?? Anyway I had to compromise a little bit with the parts.

I reprogrammed the attiny2313 in BASCOM. In BASCOM there is a function (readHiTag) which reads the data coming from the CHIP and makes them into the 5 HEX numbers needed.

Making the board for the MODELA milling.

U2270B is not in the library of Eagle.
I had to construct the U2270B part in EAGLE and make the board. Because I was using only one layer I puzzled around with “big” resistors to make some crossings.

Here are some pictures of the board and the schematics, files will be added if all is tested and works.

I printed the board on paper to see if the parts would be fitting.

There were a few problems: the capacitor below the chip was too close and the connections with the coil were too small, so the copperfoil came off from the board.

But testing the rfid board and chip worked! (The script was in basecom and the chip I used was ATTINY2313 )

Stupid was not to give the resistors a value in EAGLE, I made the mistake of putting the wrong ones in, thinking all of the resistors were 10K….:-(

So I made a few modifications and at the same time made the board more five sided 🙂

This is the rectangular old board, here is the five sided new board: