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Topic: Steering a combine via GPS (Read 29383 times) previous topic - next topic


I'm looking at this thread and your pictures a second time, Lance, and I am still amazed this was your first Arduino project! Although it does seem like you have to have had some kind of chops under you belt; you have an o-scope, and there was programming and the custom circuit involved...so I have to ask:

Why are you a farmer and not a circuit nerd like the rest of us?  ;D

Where did you pick up your skills? What made you decide to void the warranty on your tractor (does Case know about this?)... ;)

LOL - actually, I like the custom enclosure for the Arduino and interface PCB - I think I have one in my fridge holding some leftovers! The only thing I would suggest (though you say you are moving to a different platform, and it seemed to have held up anyway) is to blob some hot glue on the i/o sockets and wires to/from the Arduino (and maybe the USB connection, too) - I am really surprised that the vibration and such didn't pop those loose! Really they should be soldered in place, rather than stuck in the headers.

Wow - great job!
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.


Thanks for the kind words.

I guess I am a circuit nerd, just not in the professional sense. I enjoy waking up whenever I feel like it (usually ~10AM). Did the IT thing for a while, but I eventually realized that I would never get rich working for someone.

My o-scope and basic electronic skills are from college. Programming is self taught. Currently trying to learn C++ on Eclipse (which is a sucky platform compared to microsoft visual anything).

Warranty on new equipment is typically 1 year, so my test mule was well out of warranty. The iron manufacturers are aware of what I'm doing, but their employees can't say much in public, such as on a forum.

I've never had an issue with connections vibrating loose.



mx270a as a fellow farmer I'm very impressed by your project! I have just started out with my Arduino and my first little project will be using it as a seed monitor on my little 4 row JD planter.

We have a old 4420 JD combine with no automation at all, was just wondering how do the newer machines get a measurement of the incoming bushels? Are they using sensors in the clean grain auger?


Yield monitoring on a combine typically uses weight sensor to feel how much impact the incoming grain has as it comes in to the hopper. They put the sensor at the top of the clean grain elevator so as it comes up the elevator and gets thrown off at the top, the grain hits the sensor. There is also a moisture sensor to calculate shrink. Test weight has to be estimated, which is where you will get a lot of error when going from one hybrid to another.

The system will need to be calibrated for different flow rates. There are also patents on the algorithms. Ag Leader uses a curved calibration line, and John Deere is linear.

The newer systems use CanBus sensors, so if you feel like sniffing the bus, you can pull the raw data and try to calculate it yourself.


Lance, I have found this whole thread amazing! from the Arduino side as well as farming side.  I was raised on a "farm" - tiny compared to your setup. So small I can remember cutting cotton stalks with a pair of mules!  Then we got a two-row tractor to go along with the one row tractor we had.

The scale of farming on those big farms is amazes me.

Good luck and keep us updated on your projects.

Ken H>



What Ard. board did you use? What is best for something that moves faster, about 10 mph or so?



Originally I was using a Duemilanove that was wired to a prototyping PCB that had some TO-220 MOSFETs for switching higher amperage power that controlled solenoids on the steering valve. I have since developed a couple PCBs that have everything I need on one card - power regulation, the ATMega, TTL-to-RS232 translator, valve driver MOSFETs, and some sensor inputs.

A vehicle that moves at 10 MPH will have very accurate heading data at that speed, but a tiny amount of heading error will drive you away from your desired path quickly. Getting accurate heading data will still require a yaw sensor coupled to a magnetometer or GPS.

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