Any Electronics Gurus Out There?

[npalen]

Iam a bigger fan of raspberry pi and would probably consider using a d/a (digital to analog) converter and opamps. Another option would be to use a potentiometer to drive a 0-10 VDC output with an AP4003.

https://www.eurotherm.com/?wpdmdl=27308

GPIO - Raspberry Pi Documentation
MAX5661 Single 16-Bit DAC with Current and Voltage Outputs for Industrial Analog Output Modules
MAX77816 High-Efficiency Buck-Boost Regulator with 5A Switches

A rough sketch of what you're proposing would be nice. You lost me rather quickly.

 

[Grumpycat]

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.

 

[npalen]

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.

 

[Grumpycat]

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.

 

[quicksandfarmer]

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.

 

[ddbackhoe]

A rough sketch of what you're proposing would be nice. You lost me rather quickly.

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]

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.

 

[npalen]

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.

How does an open source project get started. Does someone have to be the "moderator" to assimilate, monitor and judge etc?

 

[npalen]

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.

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.

 

[npalen]

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

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.

 

[npalen]

This is looking at the end of receiver and it looks like the only way to disassemble is to remove these plugs first. The large end cap is aluminum but the plugs are ferrous metal of some kind.
I'm wondering if this is a fairly common way of "sealing" electrical components and whether they could be drilled out to gain access?

Edit: Guys, again, I really appreciate all the input!

 

[Industrial Toys]

Just wondering. Hard to think what someone elses brain is scheming. Does a simple system even need to know where the machine edge is in an application like this?. As with manual control, you either raise the cutting edge, lower it, or leave it in place. Why any positioning sensiing data or proportioning valves. The Up/Down circuit hardly goes fast enough to think about having to control it's speed. There does need to be a limit switch for up and down, end of travel to stop the hydraulic circuit at either extreme.

My question in considering running my harley off a laser, are that the mahine has only a foot or less of adjustment. The laster only has a foot or say of capture area. So if you are a couple of feet off grade, how does the system know whether you are high or low when the reciever isn't seeing the laser? Am I missing something?

BUT beyond that issue, if I was trying to do it. I would try and get at the indication LEDs. Connect those to the opto coupled input of a miniature relay board. Possible add some timing capacitors to avoid quick pulses. Then simply drive the joystick operated electrically operated front aux circuit that I reroute to the rear of the machine and the Harley up-down cicuit.

Doing it with another arrangement of hydraulics, I might opt to drive two larger relays from the miniature relay board that then drives the solenoids.

If I was into PLCs that may be the way to go, offering unlimited adjustment and parameters. There are too many of those around to have settled on a brand to get to know.

 

[npalen]

Just wondering. Hard to think what someone elses brain is scheming. Does a simple system even need to know where the machine edge is in an application like this?. As with manual control, you either raise the cutting edge, lower it, or leave it in place. Why any positioning sensiing data or proportioning valves. The Up/Down circuit hardly goes fast enough to think about having to control it's speed. There does need to be a limit switch for up and down, end of travel to stop the hydraulic circuit at either extreme.

My question in considering running my harley off a laser, are that the mahine has only a foot or less of adjustment. The laster only has a foot or say of capture area. So if you are a couple of feet off grade, how does the system know whether you are high or low when the reciever isn't seeing the laser? Am I missing something?

BUT beyond that issue, if I was trying to do it. I would try and get at the indication LEDs. Connect those to the opto coupled input of a miniature relay board. Possible add some timing capacitors to avoid quick pulses. Then simply drive the joystick operated electrically operated front aux circuit that I reroute to the rear of the machine and the Harley up-down cicuit.

Doing it with another arrangement of hydraulics, I might opt to drive two larger relays from the miniature relay board that then drives the solenoids.

If I was into PLCs that may be the way to go, offering unlimited adjustment and parameters. There are too many of those around to have settled on a brand to get to know.

The system knows where the cutting edge is at without any "position sensing". That is the function of the laser receiver and if out of range more than a few inches it is very obvious just by looking around at the terrain. The laser and electronic height adjustment system comes into play in only the last few inches of level. I agree on the limit switches.

Keep in mind that this system is not for smoothing contoured areas but rather dead flat or a precise preset slope(s). GPS control would be the exception.

I like your idea of using the auxiliary circuit but you would still need a directional solenoid valve to automate. Right? The joystick with push button would be nice to quickly allow other functions such as 3PH when needed. It would serve to quickly switch between manual and auto mode then using any needed remote valves for manual mode. A maintained switch might be better than a momentary push button, however.

Thanks for your interest and input!

 

[npalen]

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.

Can you link to a recommended rasberry pi kit or combinations for this project?

Here's some possibilities:
Amazon.com : rasberry pi

 

[hawkeye08]

Found an interesting utube for RPI and relays.. RASPBERRY PI All About controlling Relay Boards for Home Automation - YouTube I don't know how many amps your controls would need..

 

[kenmbz]

Found an interesting utube for RPI and relays.. RASPBERRY PI All About controlling Relay Boards for Home Automation - YouTube I don't know how many amps your controls would need..

Remember a solenoid is an inductor, so you;ll need a capacitor somewhere to stop it from fluctuating. I used to do machine control. I like IR, but out in the sunlight they don't work well. Could use Bluetooth or wifi on a PI or arduino to make the commands , would just need to understand the delay as it's pretty long for wireless. 2 Pi-one on level-one for control and some simple switch codes with a small delay built in to stop resonance.

 

[npalen]

Remember a solenoid is an inductor, so you;ll need a capacitor somewhere to stop it from fluctuating. I used to do machine control. I like IR, but out in the sunlight they don't work well. Could use Bluetooth or wifi on a PI or arduino to make the commands , would just need to understand the delay as it's pretty long for wireless. 2 Pi-one on level-one for control and some simple switch codes with a small delay built in to stop resonance.

Would you know what type of sensor is used or could be used to pick up the red laser beam directly? There's a closeup pic of them in one of the above posts. Looks like 600 RPM is about max for some/most of the rotary laser levels.

Thanks for joining the conversation!

 

[npalen]

This is a California company that shows the only Machine Control System Electronics Package that I've found to date short of a full blown machine package.

The links shown are the company, the product and the owners manual.

https://cdn.website.thryv.com/92ba9...aser-Tech Model 312 Machine Control Panel.pdf
https://irp-cdn.multiscreensite.com...b36/files/uploaded/312-367 Manual 03-2018.pdf
https://irp-cdn.multiscreensite.com...b36/files/uploaded/312-367 Manual 03-2018.pdf

Some good info on what goes into a "package".

 

[quicksandfarmer]

I've done a lot of business process automation. The thing I like to tell people is you have to be able to do it manually before you can automate it. So I would work on getting it manual before trying to automate it. Here's what I mean: try putting an electric control on the blade height adjustment with two buttons, one for up and one for down. Can you come up with a simple set of rules based on just the lights from the level that allows you to do the job? An example of simple rules might be, if the "high" light comes on, push the "down" button until the light goes off and if the "low" light comes on push the "up" button until the light goes off. A more complicated set of rules might be if the "high" light comes on, push the "down" button for one second and then check the "high" light.

Does that set of rules give you the result you want, with all terrain, soil conditions and speeds? Because if you can't come up with a set of rules that allows you to get good results with you acting as the computer, the actual computer is never going to be smarter than you. If it turns out that you need additional information -- speed, soil type -- you need either additional inputs (speed sensor) or a way for the user to input settings into the computer.

This approach also allows you to attack the problem in a divide-and-conquer way which allows you to work methodically. You'll never get something like this working if you try to do everything at once. I could see a process with the following steps:
1. Implement electric control of blade height with manual switches.
2. Devise rules for controlling blade height based on height sensor (and other sensors and inputs as necessary) using manual switches.
3. Devise way for reading height sensor from computer (and other sensors as necessary).
4. Devise way of activating blade control from computer.
5. Program computer to follow rules, read sensors and control blade.

 

[MossRoad]

Logic and order? Baw haw haw hawwww that's crazy talk! :laughing: