How are the AB lines calculated

Correct Torriem, originally AOG never compensated for being straight north at the start of the field, so that was a good fix. Never really sure how all the different mfrs do their calculations but have found that with Trimble in our Case 500 where we have both, AOG calculates exactly the same way and the line is dead on across a half section (1.6 km)

Do you have AOG driving your 500 yet? Or just doing section control and mapping?

I hope to get that going this spring - but oh my so much harvesting to do first. I wish i had a heated shop.

Was wondering if i could just change the solenoids in the autosteer control valve and control them with pwm. They are all canbus right now of course

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Oh man!

I’ve no doubt it’s totally doable to replace the head with pwm.

Or canbus is also a possibility. I’ve got quite a few projects in mind involving canbus. By summer maybe I’ll have to find out what messages are originating from the NAVII controller and heading to the steering valve. Canbus can be noisy because of the broadcast nature of it, but sniffing across a bridge makes it a bit easier because you can focus on messages originating from a device. I can’t think the steering valve messages are all that complicated.

I was told the valves on the case artics use a ratiometric proportional control rather than PWM, couldnt plug our old autofarm into the valve block. Anyone familiar with ratiometric control?

Maybe it is a Danfoss valve?
I think solution is found here .ino for PCB+MD13S+Danfoss valve

Danfoss PVG proportional control valves - Hi Power LTD

](Hi Power LTD)
hl=da&sl=en&u=Hi Power LTD)

Danfoss PVG proportional control valves … as default on all valve sections; Hydraulic actuation; Electrohydraulic actuators PVE ( Ratiometric , 0-10V, CANbus) as

Ratiometric generally means output based on supply voltage. For example, a thermistor temperature sensor may have an output of 50mv/volt so the overall output or range depends on the supply voltage powering it.

Now inherently, all valves would be ratiometric since the more voltage across the coil for the same proportional on/off cycle would allow more oil to flow. As the voltage goes from 12.6 to 14.4v the valve output will change accordingly.

Taking advantage of the initial topic, and apologizing for the English translation.
Perhaps it has already been discussed on some forum page, but what would be the basic configuration to operate only in line following the pattern of the outline made at the beginning?

Always in line without turning.


Are you referring to contour?

I am looking for a low cost solution. Very low (income from a small Brazilian producer). Pilot in line.

The software is free, the hardware is quite inexpensive.

Taking advantage of Brian Tee, I want to congratulate the work of everyone involved in the project! Great.
My question:
I’ve been studying the forum since the first post and I realized that the use of AgOpenGPS is getting very professional and $$$$ due to the precision (it’s the natural way).
I would like to know from the veterans if I can use AgOpenGPS with low cost GPS (Ublox M8N or GPS USB) to work in line from point A to B. Without making the turn at the end.
There is a very large group of farmers who work with scrapped machinery here in Brazil, it is not cheap to keep up with technology.
I thought about using the following configuration:

  • BNO 055
  • MMA 8452
  • WAS
  • GPS M8N
  • Steering motor

Could I do a satisfactory job?
Would my direction error be too big?


Sorry my english from google translator.

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RTK, ardusimples … a lot of precision does cost a lot of dollars.

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Compared to what is being sold on the market today, AOG with RTK is not $$$$.

However I believe your M8N could work fairly well for many purposes, even with just GPS accuracy equivalent to WAAS.

If you build a system using AOG, and find that your GPS is inadequate, then it is quite simple to replace the GPS with something better. This is unlike commercial systems.

So it’s worth building an AOG setup with the hardware you mentioned.

To further reduce cost, you don’t need the bno or the MMA. If you have relatively flat land, just the gps is fine.

Hello Marcio
Personally I think that without RTK correction you will be quickly disappointed even for manual guidance.
With an M8n the precision will not be regular.
The advantage of RTK kits like Ardusimple is that they are very easy to use and that there are a lot of people to help you here in case of problems.
This is only my opinion but I think that the money spent more at the beginning will quickly recover and the high precision will allow you other uses.

Don’t waste your money with the M8N you will be disappointed very quickly, if ardusimple is too expensive for you try the M8T with RTKLIB instead…


I have some C94-M8P left. Do you want them?

Hello Peter_S!
How much do you want for two of them?
I will think about the possibility of setting up an RTK.


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Márcio I trying to other Brazilians to start to develop together! How I can contact you?