Hello all and thanks in advance for any help.... I am new here and new to arduino and coding. I will try and provide as much information as I can to get help. Let me know if you need more info and I will do my best to provide it.
I have found two threads on this forum of people adding setworks (a computer controlled sawmill operation that adjust the bandsaws height), both are useful, but neither of them are doing what I want to try. My bandsawmill is lifted up and down via a 1000 lb winch at the moment. I am posting a link to a video here: Ugly homemade sawmill - YouTube
of it in operation. If you fast forward to around 50 seconds you can see that the winch is connected to a cable system with pulleys that lifts the sawmill head up. I am guessing the head that is lifted weighs some where around 150 lbs.
My first question is: Do you think that a stepper motor (fairly inexpensive less than $100) connected to a planetary gearbox (not sure what ratio 40:1??? would be capable of maneuvering the head up and down on this cable system?
If this isn't possible, what would the easiest/cheapest way to achieve this??
What I would like to do is add a stepper motor connect to an arduino and be able to control the distance of travel up and down via the stepper motor/arduino and buttons. I have a code that was written that did something similar, but it uses chain and sprocket and also has a spring (similar to a garage door spring) to help counterbalance the weight of the mill head. (his mill head is much heavier than mine). I would appreciate any and all guidance... Thanks!
I would guess that you would require a pretty beefy stepper for this and a correspondingly capable driver. Given that, it may be hard to meet your desired budget. Especially because you'll probably find that it takes several iterations with different motors/gearboxes before you get it working the way you want it.
I know it will be speculation, but what size stepper/ gearbox would you think to lift something this weight?... It is not out of the realm of possibility to add springs to help the stepper motor..
Ex. I want to program it to have a button that you press and will move the saw head up 1". I'd obviously have to calibrate it to determine how many "steps" it would take, but that is the idea. Thanks for the replies.
neketege88:
Ex. I want to program it to have a button that you press and will move the saw head up 1". I'd obviously have to calibrate it to determine how many "steps" it would take, but that is the idea. Thanks for the replies.
And your plan to hold that position is what? Bet the winch has a brake to stop any movement.
Paul
neketege88:
I know it will be speculation, but what size stepper/ gearbox would you think to lift something this weight?... It is not out of the realm of possibility to add springs to help the stepper motor..
NEMA23 or 34 could easily lift 1000 pounds.
Drive leads screw.
Calculate thread ACME screw resistance
Most milling machines are well past that.
dave-in-nj:
NEMA23 or 34 could easily lift 1000 pounds.
Drive leads screw.
Calculate thread ACME screw resistance
Most milling machines are well past that.
Would this require some type of gearbox to lift this weight? Or could the ACME rod be fastened directly to the motor and the frame of the mill? I'm not opposed to changing my setup to ACME screws, and nema23s I actually have a pair of nema23s not sure what amperage or torque they have or would need?
Also, I am not opposed to using an encoder either, but I don't know much about them or what would work for this project. The head lifts approximately 25". I am not sure how many cpr would be necessary to give an accurate reading either. What would I need to be looking for? Thanks!
You may be able to connect an encoder to the existing winch. If the motor is geared down a lot (I guess it is) that can be as simple as a dot on the drive shaft of the motor and count full rotations using an optical (IR) sensor. That's likely the cheapest solution, and guarantees a motor that's up to the job.
If you can tell us more about that motor (type, voltage, current) we can suggest ways of controlling it using an Arduino. If it has its existing controller you may even hook up your Arduino onto that, it could be as simple as mimicking the button(?) controls you now use for it.
JCA34F:
How fast do you want the head to move upwards, 1" per second? 10" per second?
The video didn't show even a glimpse of the lifting mechanism.
It doesn’t need to go fast at all 1” per second would be plenty fast. 1/2” per second would be fine. Sorry about the video. It was the only one on hand. I can get better pictures or video if needed.
wvmarle:
You may be able to connect an encoder to the existing winch. If the motor is geared down a lot (I guess it is) that can be as simple as a dot on the drive shaft of the motor and count full rotations using an optical (IR) sensor. That's likely the cheapest solution, and guarantees a motor that's up to the job.
If you can tell us more about that motor (type, voltage, current) we can suggest ways of controlling it using an Arduino. If it has its existing controller you may even hook up your Arduino onto that, it could be as simple as mimicking the button(?) controls you now use for it.
I don’t have the specs on the winch motor. It’s a 25 year old atv/boat winch. 12v dc that I isolated the brushes to enable it to go forward and reverse when polarity is reversed. I’m not sure of current draw but looking at similar on the internet 20 amps at full load and yes geared way down. Probably rated at 1500 lb. it does have a brake to stop the head from moving down. I can control it both with a simple toggle switch that’s connected to a solenoid/relay and i also have a wireless remote (I’m assuming IR) that will control it.
I don’t know anything about the optical sensors you are talking about, but the machine does vibrate pretty good while cutting not sure what effect it would have on the sensor, but I like the idea! Thanks!
That kind of motor should be pretty straightforward to control back and forth with an Arduino, provided you have a sufficiently powerful motor controller (H-bridge). Relays also work but don't give speed control.
The sensor system would of course have to be ruggedised. Vibrations, chunks of wood flying around, water, dust, whatnot.
the winch will be a DC motor with a gearbox to gear it way down.
as wvmarle said, adding a simple reflective dot and a cheap IR sensor module will allow you to get motor RPM
I would suspect the existing motor is OFF/ON only and the motor runs at full speed.
the hack would require getting access to some part of the motor,even the end of the shaft, but that may be easier said than done as most sit in the front of a vehicle and are subject to all weather.
to test, I would get an IR module and put a series of dots on the drum, make your own encoder. see how easy it is to get a distance.
as for the lead screw, there are lots of home made mills that use screws and a motor to drive the lift. spend some time with youtube.
wvmarle:
That kind of motor should be pretty straightforward to control back and forth with an Arduino, provided you have a sufficiently powerful motor controller (H-bridge). Relays also work but don't give speed control.
The sensor system would of course have to be ruggedised. Vibrations, chunks of wood flying around, water, dust, whatnot.
I am completely new to arduino and programing. I know I am going to have to do a lot of studying.... Am I understanding you correctly? I would connect an H-Bridge (high amp above 20) to the arduino, and write some code that would allow me to run a button to the arduino board that when pressed would signal the h bridge to run the motor some set variable that I could calibrate into a certain amount of movement of my head via the winch/cable system I already have? Please forgive my ignorance if this makes no sense. Thanks for the help!
dave-in-nj:
the winch will be a DC motor with a gearbox to gear it way down.
as wvmarle said, adding a simple reflective dot and a cheap IR sensor module will allow you to get motor RPM
I would suspect the existing motor is OFF/ON only and the motor runs at full speed.
the hack would require getting access to some part of the motor,even the end of the shaft, but that may be easier said than done as most sit in the front of a vehicle and are subject to all weather.
to test, I would get an IR module and put a series of dots on the drum, make your own encoder. see how easy it is to get a distance.
as for the lead screw, there are lots of home made mills that use screws and a motor to drive the lift. spend some time with youtube.
Again, I am new so please bear with me. I am willing to research and learn. Is there something specific I should be looking for in ordering an ir module to do the test you are talking about. When you are saying build my own encoder, I am lost.... Would this mean something simple like using an old roller from a computer mouse or am I way off? I really appreciate all the help and enjoy learning about this..
Heres a link to a better video of the winch/cable system.... it is outside now, but usually does have a top over the saw mill head. Winch lift sawmill - YouTube
In this context, make your own encoder means use the IR detector to have the Arduino count the dots you put on the motor. That'll give you rpm that you can use to calculate distance travelled.
Just that you don't care about the rpm as much as you care about counting the actual number of rotations the motor has done, regardless of how long it takes.