Arduino Pro Mini + ID-20 RFID + USB-BUB not working well

Wireless & IoT
1

Background:

I am playing around with a number of Arduino chips, one I plan on using to build a simple RFID door lock. I chose the [Arduino Pro Mini 328 because of its size and cost.

I wanted to pair this up with the [ID-20 because it has a little better range than the ID-12 for a small amount of $$ more.

I had a [USB-BUB that I used for programing a Sanguino. It is a FTDI programmer so I thought I could use it for programing the Arduino Pro mini, and it turns out I can!

After playing around with some simple code, which basically listens to the serial port and displays ASCII when it hears something, I kept getting garbage output, but output none the less every time I passed a RFID card over the reader.

I gave up on the Pro Mini and tried my Arduino MEGA, this worked without a hitch on the first try and displayed the correct output to the screen. After further trial and error I found that by setting the Pro Mini to 9600 and the serial port listener to a higher speed, I believe the 115200, I dont recall at the moment. But setting both the code and listener to the same higher speed did not fix the problem.

Question:

So, I am thinking, is the USB-BUB that I am using to program and listen to the serial response set to a specific baud rate? Because even printing out “hello world” is giving me garbage unless I configure things as above. Regardless, is there a way that I can fix my code/hardware so I can see correct output on the serial monitor?

Also, when connecting the serial out on the ID-20 to the RXI on the Pro Mini I have to unplug the wire each time in order to program it or else the upload to board fails. Can I put a diode or something similar onto the serial out from the ID-20 to prevent this error when uploading?](http://wulfden.org/TheShoppe/pa/index.shtml#BUB)](http://www.sparkfun.com/commerce/product_info.php?products_id=8628)](http://www.sparkfun.com/commerce/product_info.php?products_id=9218)

2

Well I did some more searching around the internets and I found a few helpful resources. Here are two links…

[This One is from wulfden where I got my USB-BUB and had a pretty good article and sample code on how to get the arduino to read RFID tags with the ID-12 or ID-20. The code and hardware worked great on my MEGA but no response at all from the Pro Mini yet I can program it just fine and everything else appears to work.

On that site I also found out that the serial wire connecting the RX on the arduino and the pin 9 data out on the ID-20 needs to be disconnected while new code is being uploaded to the board. Still wondering if this is something that a diode can fix at all.

I also found [This Link which talks about how to use the software serial library to get the ID-20 to talk to a mini. I did not get a chance to try it yet but I plan on doing it if nothing else is working with the Pro Mini.

Anyone know why the same code and hardware works fine on my Mega but not on the Pro Mini?](http://blog.formatlos.de/2008/12/08/arduino-id-12/)](http://wulfden.org/TheShoppe/freeduino/RFID_ID12.shtml)

3

After talking to a few people on the sparkfun IRC channel and emails with sparkfun support I may have located the problem. I am uploading the sketches to my Arduino Pro Mini 328 with the board setting of LilyPad ATmega328 (as I was lead to believe this is the correct setting from the arduino.cc web site about the Pro Mini). When I get home I will try setting it instead to the standard arduino ATmega 328 board settting and see if this changes things at all.

4

I changed the board setting to ATmega328 and everything works fine now!