Archive for March, 2011

It’s always nice when you for the first time see the data you have been trying to get across a wireless (Jeenode) link arriving :

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The “Hello!” messages are just part of a heartbeat mechanism to make sure the link is actually operating.

The digits are the number of the RFID chip I was trying to read.

So in other words now I have a wireless reader (Jeenode) of RFID cards transmitting it’s ID to a central Jeenode receiver.

We have liftoff!

I was getting the error :

/Library/Ruby/Gems/1.8/gems/activerecord-3.0.5/lib/active_record/connection_adapters/mysql_adapter.rb:623:in `select’: undefined method `more_results’ for #<Mysql> (NoMethodError)

in one of my old ruby applications, I got out of it by going to line 623 of the /Library/Ruby/Gems/1.8/gems/activerecord-3.0.5/lib/active_record/connection_adapters/mysql_adapter.rb file and commenting it out. Like this:

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And then Wikipedia gives us a insight into my story about the extortion scam Thai police/mafia is running – http://en.wikipedia.org/wiki/Thai_police – see the section on conduct. This seems to indicate that extortion of parents by holding their kids hostage is common practice.

So in other words a thoroughly unpleasant country – so no more holidays there – ever.

image1914181536.jpgA frosty morning in Surrey.

While I still remember how I put this together – here it is.

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The trick is that the ID-12 requires +5V to power it, the Jeenode runs off +3.3V.

So feed the Jeenode (through the power pins) with +5 v, the power regulator will fix the rest for you.

The next problem is that the TTL serial port logic from the ID-12 works on 5Volts. So we need to make a voltage divider from 2 resistors between the serial port out (pin 9) – and as long as the resistor closest to the serial port is twice the value of the resistor to ground otherwise the Jeenode serial input port will not read the data.

I added a LED to port 10 – it helps in debugging where you can see that the ID-12 outputs data if it reads the RFID chip correctly.

Brits have always had a strange relationship to their pets – they are sometimes (often) more important than their kids and other humans.

So I was not too surprised when I found this leaflet at the vets:

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It’s basically a service that turns the ashes of your (presumably dead) pet into a small “diamond” to put into a ring or other ornament…..

Go figure.

At long last our first working RFID reader prototype

IMG_7100 (Click for larger image)

Using a ID-12 reader and a couple of 125khz RFI cards it all worked out fairly easily.