SparkFun Forums

[Madeleine Hopkins]

Right now I have pin 11 to 5V, pin 1 to ground

Following this thread, I've connected pin 1 to +5VDC, pin 11 to ground

Ray, I think you have swapped these two pins.

Regards,
Madeleine

[arpitjoshi]

Hello friends,

i am naive at electronics and am trying to us Id12 by connecting it with ATMEGA32 on STK500. the that i want to know is that if i want to connect stk500's led at pin 10 then do i ned to connect 1k resistor

[arpitjoshi]

Can someone provide with the sample code for initializing the USART when communicating with ID12.

[raygeeknyc]

Right now I have pin 11 to 5V, pin 1 to ground

Following this thread, I've connected pin 1 to +5VDC, pin 11 to ground

Ray, I think you have swapped these two pins.

Regards,
Madeleine

Thanks Madeleine
I think that I had wired it up correctly but wrote it up wrong here. I had broken it down so I've just recreated it on the breadboard, making certain that I've got it right this time, but still nothing.
With this correct pin assignment:

I've connected pin 11 to +5VDC, pin 1 to ground, pin 10 to a 1K resistor which leads to the positive lead of an LED which is then connected to ground.

I hook this up to power, pass some HID cards by the ID12 and... nothing.

I have a few questions:
1) Is this enough of a circuit, and plan, to test this chip? Should the LED light?

2) How sensitive is this to variations in power? My power is actually +4.4 VDC according to my multimeter.

3) What is a good alternative for a simple test circuit if any?

Thanks again,
---Raymond

[Madeleine Hopkins]

I have a few questions:
1) Is this enough of a circuit, and plan, to test this chip? Should the LED light?

a, make sure RES (pin #2) is wired to +5V
b, make sure FS (pin #7) is wired to GND

Then pin #10 should go high when a tag is read.
During the time when pin #10 is high, the serial data is sent on pin #9.
This has worked flawlessy in our lab.

2) How sensitive is this to variations in power? My power is actually +4.4 VDC according to my multimeter.

I would check with +5V first and then experiment with lower powers if needed. No need to add several risk factors.

3) What is a good alternative for a simple test circuit if any?

4 cable-connections and 2 wires as such:

RED => +5V (pin #11)
BLK => GND (pin #1)
YEL => D0 (pin #9)
GRN => LED (pin #10)

Wire #1: from RES (pin #2) to +5V (pin #11)
Wire #2: from FS (pin #7) to GND (pin #1)


Now connect RED to +5V, BLK to Ground.

If you have an oscilloscope, measure on GRN, and swipe a tag. It should go high when ID12 is reading. Now measure on YEL. It should be high. (inverted TTL-level). Swipe a tag and you should see serial data here.

After this test:

Connect YEL to data in (TTL serial on e.g. AVR/PIC)

(Optionally: Connect GRN to resistor and LED or transistor + beeper. Do not drive anything directly from pin #10).

[raygeeknyc]

Madeleine, thanks so much for your help

I've recreated this circuit on a breadboard and hooked it up to a (measured) 5VDC power supply.


(The ID12 is soldered into the Sparkfun breakout board)
The resistor is 1K, from pin 10 to the LED

The following pins are connected:
1 - GND
2 - +5VDC
7 - GND
10 - 1K - LED - GND
11 - +5VDC

When I switch the power on, I see a brief flash on the LED.
My test is simple enough, I have 2 HID cards (my building security cards from work). I pass either of them over the ID12 module, between a half inch to an inch from the module surface. No LED activity to be seen.

Is there anything wrong with this circuit that anyone can spot or do I have a defective/damaged module?

Thanks
--Raymond

[etracer]

Are you sure your cards are the correct type of RFID cards? They need to be 125KHz with this module.

[busonerd]

They need to be 125khz, and a particular protocol / encoding. The ones from SparkFun Electronics definitely work.

Cheers,

--David Carne