Not Quite Normal

Open source catflap firmware June 7

While CATaLOG was a success most of the time, the most unreliable bit of the system was detecting the RFID tag as the cat went through the door. The system has been offline since June 2010 and we also changed our priorities from tracking the cats in and out to making sure they were safe at night. We purchased a PetPorte RFID catflap which not only reads the cat's embedded microchip reliably, but also imposes access control and has a light sensor so when it gets dark it will only let the cats in, not out.

PetPorte was a UK company and were planning to release a 'computer connection kit' until they were bought by Staywell, when all progress on that front ceased. Upon inspecting the PCB there are headers for additional antenna, programming and serial, so I hooked up a Bus Pirate to see if anything was happening. Nothing was but it seemed I was not alone in my quest. Through emails sent by forum members it transpired PetPorte had signed a 3 year NDA with Staywell and couldn't give us any info on how to make the catflap talk to anything. Yet. So we resigned to waiting until the NDA expired and going from there.

It appears someone couldn't wait this long however and released his own complete rewrite of the firmware. Not able to read the code out of the PIC he just reimplemented the whole firmware from scratch, including decoding the RFID signals from the OP amp into the PIC(!) He also added functionality to determine which way the door is opening via a potentiometer attached to the flap.

Open source firmware for my catflap and my PCB revision matched - Amazing!

I purchased a PICkit 2 programmer, made a lead up and set about reprogramming the catflap. Here it is in action:

This went well and after reassembling the catflap and programming in a test tag I hooked up my TTL-USB converter to the serial header, scanned the tag a few times, entered some control characters and saw this:

Hurrah! All I need to do now is hook the catflap up to a bifferboard, use the same python script controlling the chicken coop to get it on the internet and CATaLOG should be back online soon!

Adding access control to CATaLOG June 24

In the past few weeks we've been having problems with another cat coming into the house. Rather than invest in a magnetic catflap for £30, I bought a standard RC servo from Heliguy (excellent service btw - free delivery and arrived the next day) for £7 and added it to CATaLOG.

The video below shows it in operation.

The servo is connected to pin 9 of the Arduino, one of two pins which are capable of PWM output without affecting other code, and uses the basic servo library to turn the servo 180 degrees, wait a few seconds, and then turn it back

In the video I push Tuffin's manual in/out button to trigger the servo - in the live code the servo only operates when it detects Bobbin or Tuffin via the RFID reader. The lights you see flashing are the ethernet interface activity lights attempting to send a tweet and update the status :)

It needs a few tweaks to make it completely reliable (don't want the cats getting locked out!), but once it is I'll add a section to the project pages with more details.

CATaLOG enclosure complete June 18

Finally finished machining the enclosure for CATaLOG. Here it is:

catalog-exterior  catalog-interior

The Arduino is mounted onto the stripboard with a simple velcro pad (hence it being at a slight angle) so it can be removed for working on / debugging or moved slightly when inserting the ethernet cable etc. 

The posts to support the lcd were made with the help of my Dad and his lathe.  I'll document the process over on the project pages when I get the chance.

Adding an external antenna to CATaLOG May 11

I made a new antenna this weekend for the RFID reader used in CATaLOG.  The old coil is on the left, and the new one on right.

new antenna

The system is more reliable now but could still be improved.  I've documented how I added the external antenna and made the new coil over on the project pages.

CATaLOG talk video April 27

The video of my CATaLOG talk at Ignite Cardiff (complete with microphone feedback) is now available over on YouTube.

The slides are available as a PDF here

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