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npalen
Elite Member
A rough sketch of what you're proposing would be nice. You lost me rather quickly.
Any Electronics Gurus Out There?
- Thread starter npalen
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A rough sketch of what you're proposing would be nice. You lost me rather quickly.
Grumpycat
Veteran Member
I've worked on similar but different things.
The Johnson laser level has an "antenna" of detectors and a separate display. I'd look to tapping that line for my signal. But I'd also experiment to determine whether it is easier to build my own array of laser detectors or to tap one that is already built. There is no reason you can't have two arrays of detectors on one tractor. Two, a distance apart, will indicate whether the front and rear wheels of tractor are on same level. Which brings to mind another problem: if the wheels are not on the same level then the signal to the box needs to be compensated.
When controlling the hydraulics for the box you have an issue of selecting the right gain. When the laser level detects an error then just how much do you move the box? Am afraid you need a position sensor on the box because multiple lift/lower signals will likely accumulate error resulting in "neutral" being higher or lower than when you started.
The Johnson laser level has an "antenna" of detectors and a separate display. I'd look to tapping that line for my signal. But I'd also experiment to determine whether it is easier to build my own array of laser detectors or to tap one that is already built. There is no reason you can't have two arrays of detectors on one tractor. Two, a distance apart, will indicate whether the front and rear wheels of tractor are on same level. Which brings to mind another problem: if the wheels are not on the same level then the signal to the box needs to be compensated.
When controlling the hydraulics for the box you have an issue of selecting the right gain. When the laser level detects an error then just how much do you move the box? Am afraid you need a position sensor on the box because multiple lift/lower signals will likely accumulate error resulting in "neutral" being higher or lower than when you started.
OP
npalen
Elite Member
Thanks for your feedback and insight!
I'm definitely going to look at tapping into the receiver. Also I today ordered the remote display that works with the receiver thinking that it might be easier to tap in there. It offers sound indicators as well as the LED visuals.
The detector normally mounts on the implement directly above the blade. The tractor front and rear wheels are usually not on the same level except when close to finish grade. The idea is to keep the blade on grade when traveling on unlevel ground. Right?
The nice thing about running the box blade on the 3PH is that the tractor moving up and down doesn't move the blade with it as the blade is held vertically by the gauge wheels behind the blade. The 3PH is floating and acts as a parallel linkage.
Yes, I think your idea on gain is spot on. That is where an arduino or plc comes into play as the gain can be tweaked for how far the cylinder needs to move to get back on grade. I would expect a one or two second solenoid burst, for example, might be enough to get back on grade depending on how close to finish grade one is operating at. A PID might also be used as a tweaking tool.
I'm definitely going to look at tapping into the receiver. Also I today ordered the remote display that works with the receiver thinking that it might be easier to tap in there. It offers sound indicators as well as the LED visuals.
The detector normally mounts on the implement directly above the blade. The tractor front and rear wheels are usually not on the same level except when close to finish grade. The idea is to keep the blade on grade when traveling on unlevel ground. Right?
The nice thing about running the box blade on the 3PH is that the tractor moving up and down doesn't move the blade with it as the blade is held vertically by the gauge wheels behind the blade. The 3PH is floating and acts as a parallel linkage.
Yes, I think your idea on gain is spot on. That is where an arduino or plc comes into play as the gain can be tweaked for how far the cylinder needs to move to get back on grade. I would expect a one or two second solenoid burst, for example, might be enough to get back on grade depending on how close to finish grade one is operating at. A PID might also be used as a tweaking tool.
Grumpycat
Veteran Member
With the sensor mounted on the blade you have feedback. When the blade is low then raise until neutral. When high, lower until neutral. The issue with gain is that you don't want to over correct which will oscillate back and forth.
For some reason I was thinking of the sensor mounted on the tractor.
For some reason I was thinking of the sensor mounted on the tractor.
quicksandfarmer
Elite Member
It's pretty common to put a photodiode next to a LED to monitor if the LED is on. If you're doing it in the sunlight you need to either shroud the whole thing or have a filter on the photodiode so that it only responds to the wavelength of the LED.
I would also second the recommendation of using a microprocessor, and Raspberry Pi over Arduino. I started programming in the 1970's and programming an Arduino reminds me of those early days, you're constantly running up against the limitations of the hardware. Once you get the basic connection going you're going to want to add things like monitoring and logging and smartphone control and Raspberry Pi makes that easier.
This project cries out to be an open source project.
I would also second the recommendation of using a microprocessor, and Raspberry Pi over Arduino. I started programming in the 1970's and programming an Arduino reminds me of those early days, you're constantly running up against the limitations of the hardware. Once you get the basic connection going you're going to want to add things like monitoring and logging and smartphone control and Raspberry Pi makes that easier.
This project cries out to be an open source project.
This maybe better than my scribbling. Imagine the potentiometer being hooked to a pinion on a rack and pinion unit ( or a ball nut drive $$) as your height gauge. You could even use an over/under limit switch if you want. Add an analog power module like an ISL8200AM (can drive up to 6VDC @ 10 A) then add a boost converter to get the desired voltage output.
How to Interface PCF8591 ADC/DAC Analog Digital Converter Module with Raspberry Pi
ISL82��AM | Analog Power Modules
Industrial Toys
Super Star Member
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- Tractor
- Kubota R510 Wheel Loader + Cab and backhoe, JD 6200 Open Station, Cushman 6150, 4x4, ten foot 56 hp Kubota diesel hydraulic wing mower, Steiner 430 Diesel Max, Kawasaki Diesel Mule, JD 4x2 Electric Gator
I would run an opto isolator. You can employ a $2.00 timer module using a 555 timer to get rid of chatter.
EDIT: Actually there s no shortage of cheap (chinese) high quality relay modules and probably timer/relay modules on E-Bay that already have opto isolated inputs. Would be perfect for this.
EDIT: Actually there s no shortage of cheap (chinese) high quality relay modules and probably timer/relay modules on E-Bay that already have opto isolated inputs. Would be perfect for this.
OP
npalen
Elite Member
How does an open source project get started. Does someone have to be the "moderator" to assimilate, monitor and judge etc?
OP
npalen
Elite Member
So the relay or timer/relay module would be attached directly to the receiver to pick up the LED's? How much "floor space" would one take up? I'm thinking they could all be mounted on a long narrow circuit board if they are not too large. I'm made circuit boards in the past with my CNC router and its easy to make changes as the design progresses.
OP
npalen
Elite Member
The rack and pinion and pot would be to provide feedback, I assume, but wouldn't the lights on the laser receiver provide the needed feedback. I'm just trying to understand.