Let's Make Robots!


Livestock RFID reader

This is a project that I have been working on for a while. 

A friend of mine has a small farm on a hobby basis and raises sheep. By law every sheep in Norway is required to have an RFID tag in its ear. Though there are several RFID readers out there for reading this type of tags, they are quite expensive and not all that hackable. A reader like the HHR 3000 Pro would cost you about $900,- and to hook it up to an electronic weight would probably set you back another $3000. So for many hobbyist farmers this is not an option.

The base of the system is a FEZ Panda II running NETMF under C#. I could probably be made with something like an Arduino but as I needed to have several UART’s and a SD card to store data, it was much easier to go for the Panda. Also as the Panda has lots of IO pins, hooking up the HD44780 display is done directly with no serial interface and no use of the pins that would go to the Arduino style header. In fact all the pins for the Arduino shield interface are available with the exception of A0 that is used by the weight cell amplifier.

As this might be produced in small quantities I decided to go for a proper PCB. That means that reproducing the device is easy and it looks more professional.

The main box (IP65) holds the FEZ Panda II. On that the main board sits with its headers for the 2x16 LCD display and the weigh cell amplifier. It also have a small coin battery to keep the RTC running.

The RFID reader is mounted on a rod made of 16mm plastic pipe (used for electrical installations in Norway). There are several 3D printed parts on this rod and the handle has a small vibration motor mounted so the user will know when the tag is read. There is also a function on the rod for lamb fetal count, this is based on a PICAXE 18-M2.

The main board also has a Bluetooth interface so the data can be picked up by a PC, PDA or any other Bluetooth device.

One of the main uses for this device is when weighing the sheep. For this we got a 500kg weight cell of eBay and it’s hooked up to an onboard weight cell amplifier that feeds the A0 with data. The weight is constantly calculated and written to the SD card (and Bluetooth) once the RFID tag is read.

All in all a fun project and according to my friend “Weighing the heard is not work anymore. If one only could get the sheep on the weight platform faster”

With the load cell amplifier taken out. You can see the battery for the RTC

With the display taken out


The main board also have a Xbee footprint that can be used instead of the Bluetooth if so desired. The Bluetooth is soldered straight on to the pads SMD style.
There is also an option for a INA125 amplifier instead of the mounted one. A potential next version will probably have an integrated load cell amplifier.


The custom boards that I have had made for this project.

The rod also doubles as a handle for transportation.

Update 02.11.2012

As there has been some interest for this device I put a question out to GHI electronics about the availability of the Panda II. http://www.tinyclr.com/forum/topic?id=7826 and as the response was not a definitive yes I thought I might make my own custom board :-)

The FEZ Panda II sells for $39.95 but the only thing I really need is the microcontroller which cost $16.95. I still had to add my custom board on top of the Panda, so why not try to build a custom board around the USBizi100 Chipset that the Panda II is based on.

The USBizi100 is a 100pin QFP with a pitch of 0.5mm and by far the smallest thing that I have ever soldered. But with lot of flux it turned out very well. I haven't tested the complete system yet but everything seems to be working so fare.

This version has a single board holding the ARM3 microcontroller, Bluetooth, weight cell amplifier and jumpers to put the USB in host mode (for a USB memory stick).

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You keep showing off like this and you will make us all look bad. :P :D

I’m in the lucky situation that people are asking me to build interesting stuff for them. And with and understanding wife, I’m pretty much free to use my spare time on things like this.
Still I wouldn’t be able to build this without the knowledge I have gotten from LMR.

Just because it's interesting doesn't mean it's easy. I agree with birdmun, I feel humbled by your ability to constantly produce beautiful designs. Also if that is the project you just enquired regarding the rtc wakeup question you seem to have solved the problem very quickly to complete the project and you must have a very fast board producer.
I am curious about the requirement for rfid tags though. Here it is still ok to use plastic written ear tags. I must admit that rfid seems a bit kinder to the animal than clipping the plastic tags to their ears. But I guess when you are already cutting their balls off or the flap of skin off their backsides to prevent fly bite it doesn't seem to be much harm.

Thank you for your comment merser.

The RTC wakeup is for another project. That is for a data logger that will be sitting about 1 meter below the water surface in lakes, taking measurements of temperature and light from above at 1 meter and 2 meters. The goal is to have the logger working for months at the time and so cheap to produce that we can have a bunch of them.

The RFID tags used on sheep and other livestock is the yellow tags you see me using. They have the ID number written on them for farmers that will use that method. So this is not the small RFID tags you will put under the skin of your cat or dog.
So the sheep’s ear still gets pierced.

This is some fantastic work Geir! I`m curious as to how the wand will hold up over time. We repair a commercial version of these available in australia and the wands get treated so badly. Farmers often use them to whack the livestock or chuck them on the ground to chase after the animals.

The goal for this project was to build a cheap and functional RFID reader. So the handle probably won’t take much abuse before it cracks or breaks. But that’s more of a problem for the farmer. If he uses his iPhone to hammer in nails, it probably won’t last as long :-)
As this is a prototype there is still the issue of waterproofing the wand. As you see the lamb counter has the PICAXE in a socket and all the electronics is exposed. The plan is to solder the PICAXE directly onto the final version and coat everything in PlastiDip.
Thanks for your comment ezekiel181

Your builds are always just clean and perfect in a manner of speaking. Nice idea to save money by building that ear-ID reader by yourself. 

Hey SauID,

Seeing your build has made me think about doing something similar for my dad.  He is a farmer, and not young any more, and this might be able to be combined with other things to make labour saving devices (automatic gates, etc).  However to do that it would need more range than most of the available RFID cards I've seen (I'm thinking a range of a metre or more).  How much range does the reader have?  The RFID cards I've seen only have a range of a few centimetres, but to be useful to me it would need to be 1 metre.  Can you increase this by adding power and / or an antenna?

Thanks a lot,




The range of our RFID reader is only a couple of centimeters so if you need to read this from further away you probably need a bigger antenna setup. They are quit expensive but if you look around the net you probably find what you are looking for. Best of luck.

This may be in the ballpark of what you are looking for. The specs say 1 to 6 meter range( dependent on a number of things I'm sure). And yes, definately not cheap for a premade board.


My step-father is also a farmer and anything that can be added to his business to make life easier is a great idea. Good work here.