Theres been a number of mentions of this project recently and I thought it might be worth starting a thread on it. I've been reading a lot about it and am going to experiment a bit with it. For those who haven't heard of it AgOpenGPS is an open source project to create an agricultural guidance system that is non proprietary and cheap. With the commodisation of GPS technology, combined with the availability of electronic controllers like arduino it is possible to build many things today for small money that would have cost tens of thousands a few years ago. (Open source us a software term used to describe projects where the source code is openly available and can be contributed to by multiple interested developers) The AgOpenGPS software runs on a windows tablet or laptop. At a basic level you connect a usb GPS receiver and away you go, it does all your AB lines and guidance stuff and has a light bar drawn on the screen for steering. That basic setup wont be much good for anything other than spreading fertiliser on flat grassland. And only then if you've spent probably 200 on a very good receiver. But AgOpenGPS is very very extendable. It can accept an RTK correction over the internet which should make even a cheaper receiver more accurate. There is a sub project to the software around a circuit board with an arduino controller that can talk to electronic compasses and gyroscopes which will improve accuracy on hills. The same circuit board can also run an LED light bar as tablet screens are not easy to look at in the sun. The circuit board is really intended to drive auto steer motors and their are people running it with both wheel motors turning the steering wheel but also in hydrostatic systems that are capable of being steered electronically too. Another sub project involves another circuit board that joins two GPS receivers together which will allow for extremely accurate heading/roll correction by comparing the relative positions of two nearby receivers. Its fascinating stuff and is being used to control all sorts of machines. I thought a thread here might be useful on it. I'll post what I learn as I go, if anyone else does the same it could become a useful resource. A big issue with this and many other open source projects is the high barrier to entry. The people involved are very advanced users and its all voluntary so the basic how to type guides can be lacking or written at a level that still assumes a lot of knowledge. I'm hoping to gain a bit of knowledge and contribute a beginner's guide to building a grassland grade system as opposed to the full on drilling without tramlines using extreme accuracy level that many are working with this tool for.