Thats good way to do cm of border overspray if you drive fast and manually you can doble it if you add those 2 true sections. Especially good on trapezoid / curved field borders.
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There are Arduino codes and circuits on GitHub.
These circuits provide stand alone functionality and section control by AgOpenGPS. I’m using this for 5 years now.
There is feedback to AgOpenGPS in Auto and manual mode.
So simply take this.
You can realise it on a simple home made pcb or buy one. (Prototypes available)
Link to GitHub:
https://github.com/farmerbriantee/AgOpenGPS/tree/master/Support/Misc/MTZ
Video about function (2 years old but still the same) with my control box for a 1994 Rau D2:
example for 4 sections vineyard sprayer with motor pressure adustment
For this you need
Main switch: (on)-0-(on)
Pressure switch: (on)-0-(on)
auto/man: on-off
sections: on-off
relays for 2 wire motors: DPDT for 3 wire: SPST or SPDP
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I now studied the original control box with voltage meter and there is only 2 wires per motor. So when you click the switch ground and 12v switch places. Doesn’t this make it so that it is not possible to use this configuration with only 4 relays?
Yes for 2 wires you need to have 8 to switch 12v+/ground.
hello @MTZ8302
I really like the secion control you build. I’ve been reading your github but i do have a question before I might build one myself too.
I have a V4 micro PCB and use a UDP network in my tractor for all the different PCB’s, I know you have a version with the ESP32 with Wifi but is there also a possibility to use an ethernet cable? for example with a nano and an ethernet shield connected to it? Or will there not be enough pins to connect the sectioncontrol and the ethernet to?
Hi EFlonk,
the number of pins needed depends on your sprayer: how many sections, rate control (manual, by +/- motor, via flowmeter), maybe boom control.
The ESP32 code supports Ethernet (not tested with actual libs) with a W5500 chip. I use this version:
If you have some more time, some guys from the developer group are about to draw a PCB. I made one for vineyard purpose (2 sections, 2 fluids, 2 pressure controls manual +/-). Feel free to build a PCB by yourself. I also did this with a prototyping board Arduino UNO format, that I put on top of an ESP32 in UNO shape.
WiFi works good, if you have a direct access to the PCs Ethernet port. Routers cause delay. My setup is like this at the moment: PC - ESP32 w5500 - WiFi (same ESP32) - section control. See:
I’ve built a couple of versions of the hardi control box. The motors are just 2 wire and I use a dpdt relay to switch the signal between high and low on each wire. For the master on-off when using agopengps i use diodes on each section connected to the master relay so once any section is on master will be turned on and when last section is off master is turned off. Some hardi sprayers don’t have master on/off only section control.
Good evening, thank you.
I started with the GPS autosteer, I got that working and the “normal” section control is finished too. So i’m looking for my next step up.
our sprayer is 7 sections with a +/- motor, I’ve already made a seperate boom control, but that could be integrated into one PCB.
I’m curious about the PCB thats being developed, altho it might be a cool thing to do myself too, and to learn something about designing a PCB. the section control you showed in your YT video’s was that still a breadboard kinds setup? no PCB made for that?
Have u built sc for hardi hc5500 with 5 sections?
you also have this solution…
i built one for 6 recently but you have to be careful does it have rate control?
It does but we don’t use this function… I have read from CERA forum that the other functions will freak out if u use external SC, because it dosen’t see sections turing off.
yes i ran into that problem - I have a hc5500 i want to reverse engineer when i get time. It looks like your switch box needs to send section data back to the hc5500 computer(jobcom?) over the 25pin data connector. it looks like there is a wire for each section. If you are not using rate control no issue - my solution is to build a pass through box so a hardi male and female connector with a set of relays between - no switches need - use the original switches on the hc5500 to control on off but let aog force on. Forgive my drawing but hopefully gives you the idea
Do you have a link to this information on the cerea forum? I have a Hardi with HC5500 and need section control.
I thought it was ok to just use relay switching, since it’s a calibrated reflow system and the flow is the same regardless of the section being on or off?
My HC5500 actually has Jobcom which allows serial control from my Trimble monitor. I have worked a bit to reverse engineer the protocol, and am fairly confident that I can do it, but I lost momentum on the project. I’ve been using the sprayer for a couple days by flipping switches and I really miss section control. I want to do something quickly, I thought relays would be easier.
My idea of a “pass through box” looks something like this. The big cable with big 39 pin rectangle monitor connector, it’s just a common DB37 on the sprayer end.
This could be a very simple PCB that inserts between the sprayer PCB and conveyor cable. Most of the signals can pass straight through, and we could have the motor connections broken out to screw terminals or solder pads. Simple to install and simple to remove, no permanent modifications.
The sprayer control cabinet is sealed/watertight, has room for extra circuits, has 12v available, and has room for extra cable pass throughs.
I thought it would be ideal to put the relays in that control cabinet and then just run Ethernet/wifi to the tractor.
As a special bonus: the hydraulic controls are very similar, perfect place to tie a homemade auto boom height system into the sprayer.
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I’d love to hear more about your boom height! Thanks
I think I understand.
The problem is that the rate controller doesn’t now that the booms are being switched down line. The rate controller, by default, only tried to regulate when a boom section is on. So if you have your controller toggles on, then the rate controller always works, even when you change gears to turn at a headland. And if you have your controller toggle as off, then there is no regulation. Neither is ideal.
Not mentioned in the Cerea thread, but I believe there is a setting in the monitor that allows the system to always regulate even when all switches are off. That has the same negative as above - the system will regulate when you switch gears to turn around (and will then have a low application rate for a few seconds when you switch gear again and start spraying).
The Cerea author has connected to the spray monitor’s foot pedal switch to tell the system when all sections are off. For me that’s not ideal because I really want the relays out of the cabin.
I will think more on how to defeat this, but I’m not sure it’s possible without the foot pedal switch or de-coding the JobCom protocol.
Just ideas floating around in my head. I’ve strapped some ultrasonic sensors to the boom before and played with filtering the data and having a distance readout, but never any further.
I wasn’t quite able to understand through the translation how the db15 foot pedal connector worked, so I did my own test.
Shorting pins 1 (+12v sensor) and 10 (area switch) with the display menu E8.5.1 set to “high/low level” will turn all sections off. It doesn’t just turn off area, or also turns the sections off.
So you can add your section relays as normal; inline to the motors. Then an extra relay could be wired to db15. You come into a sprayed area and sections turn off one by one. Once they are all off, db15 relay turns on and all the individual section relays need to invert states as well.