Here is the project of building AgOpenGps on my Fiat F130. I thought of buying myself a Trimble EZ250 system to assist with spreading fertilizer and mowing open a field but when I encounterd AgOpenGPS i went for the challenge to get a better sytem for less and so far it is a succes.
Here is the tractor to start with.
First challenge was to solder the PCB, the second one I soldered worked and it was time to start building after testing it on my desk.
I had to remove the front wheel to give myself some room to work and in the end after trying out different places i thought it was best to mount the wheel sensor under the kingpin.
I put the pcb inside a a alumium housing next to the chair and mounted the ublox pcb with help of some tywraps.
Power comes from the socket in the back of the cab.
You can see the floor didnt really go back in place the way it was meant to.
Thanks to math i have fancy gears around the steering wheel, it was quite a fight to get the steeringwheel off, but the result is beautful.
The tablet i chose is a FZ-G1 toughbook refurbished from ebay with a prepaid simcard for the correction. A 12 charger was quite expensive so i found myself a cheap and easy way to charge the tablet.
The ram mounting stuff and the brodit tablet holder were a bit more expensive than i wished for but they were worth the money.
So far i have done some testing on the road and it seems to work quite well. Later this week ill start testing in the field and there probably will be some videos coming off perfect straight lines.
Great! Have the same tractor here, I plan to add AOG to it in the future too. Did you have any problems with the steering motor? On our tractor the steering ratio is really bad (I have to turn the steering wheel much more often to steer than in other tractors). The it the same for your tractor?
Nice mounting !
I’m working on a updated version of my steering system. With a ring gear of 96 theet instead of 81, in order to decrease the reduction ratio and to have more torque at the motor level.
Currently I have a minPWM of 70, the goal of this new design is to decrease minPWM.
For the first design, I was limited by the small print volume of my previous printer, but with my new Prusa i3MK3S+, I have greatly increased my abilities !
But for now I havent tested this new design and I thnik I won’t be able to test it before several months. If you are interested in, I can share you the new files I you want to test.
I should have to check how high my minimum pwm right now is, but so far i dont seem to have problems with the steering motor not having enough torque. For now it functions so ik not going to change to much on the set up. I foond out that calculating the exact count per degrees is fairly easy with the honeywell sensor, it has a maximum of 90 degrees and mounting it this way gives you around 88.89 counts. Later ill probably add a cmps14 but there isnt any need for right now.
I haven’t problems too with the current mounting. I just find that miwPWM at 70 is a bit high. And the new design also take into account some improvement I have in mind.
But like you, until the current design mounted on the Fiat doesn’t break, I will not change it !
Next design is just ready in case of brake of the current (so it’s why I haven’t test the new design for now).
Yesterday i worked the first field, im surpises with the accuracy with stanley steering i managed to keep it 2-3cm from the line, sometimes 6 when the cultivator pulled hard on the tractor and the topsoil was a bit slippery. So far i cant get the pure pursuit to work well and abcurved lines are also still a bit tricky for the tractor to follow. Maybe i will need a converter to run my steer motor on 24v instead of the 12v now. Charging te tablet direct from the tractor sounds like a plan, the convertor wasnt a big succes.
In working without cmps or bno085 now and have the mma turned off. Im planning on getting a cmps14 but im still figuring how to mount it and where. I think together in a box above the rear axle with an extra arduino would be the best place and way.
The best place is as close to the middle of the pivot and as low as possible. So center of the axleleft to right, front to back.
In my 2wd, it sits under the seat - works really well and is super stable.
WIth i2c extender you can go a few meters with i2c.
On the 4WD it is mounted right at the articulation joint.
you want the imu to not exhibit any non symmetric motion - different going left vs right - by having an offset. Move the thing around the cab, or even on top of the cab away from blower motors, high power etc. The ability to mount the thing away from the confines of the autosteer board is key as you can easily mount it pointing forward using a single axis.
Right now i have the pcb fixed on the floor next to the seat, so lets say i would make the cmps in the middle under the seat i could reach there without an i2c extender? If the pcb is fixed in place, leveled and pointing forward, can i then use the place for the mma or should i still use jumper wires to give it another place?
Was is the honeywell rty sensor.
Tablet is a refurbished panasonic fz-g1
The pcb is pcb v2 from Brian
Motor is the phidgets motor running on 12v for now, have a 24v converter laying on the shelf.
Currently no sensor for roll, the mma isnt stable enough for me, but im planning on using cmps14.
The gps is from ardusimple with the simple ublox receiver.
I wish you good luck with building it on such a nice tractor.