Fix the axle on both sides. Modify the pen servo holder to a linear actuator that can lower or lift the pen from the paper. Make sure the belts are as parallel with each other as possible
Making the belts parallel with your axis instead of on an angle will increase your accuracy a lot. You could also put the pen in a tube to travel vertically up and down and have the servo arm drive a pin on the side of the pen up and down.
Keep at it. Even a wooden dowel would work well as a shaft, . Even better if you had a top/bottom roller that were mated with gears to provide opposing drive function, but that would add to the mechanical complexity. At the minimum constrain the opposite side, and for added results, constrain the back of what the paper slides on to the shaft with some springs or something to make sure you get good traction. Your pin could also stand to be transposed a little bit off axis so that the rotation results in more upward movement of the tip, and less horizontal movement of the tip. That would require the servo actively apply torque to push the tip into the paper. Conversely, just print a little channel, and put a rubber tire or whatever on the servo so it acts like a rack and pinion. Put the pen into the vertical channel, which constrains it into just moving up and down, and then the servo can push down on it as needed, though that will likely result in some slippage. This could be fixed with gear teeth or with a linkage.
I made one of these for one of my engineering classes and I would love to send you the files if you want. I used paracord as a drive belt in my design. I love the way you move the pen off the paper with another servo motor. That's a functionality that my design did not have.
Hey brotha, just commented on the short but this provided good insight for me to get some ideas. The coat hanger should work as long as you fix it on the right. Still not sure on the necessity of the servo unless you definitely want a dotter, in which case it would work better with the pen on a 1 inch horizontal lever, then drive the servo way less. This will simultaneously allow the pen to overpower the servo a few mm with the torque from being offset (should increase your success rate of pen contact) as well as allowing you to more accurately affix it to the system since the pen itself will rotate much less. Im by no means a pro but I finished mechatronics with a 100 if you have any specific questions 😎😂
Excellent! The idea of moving the pen is much better than what I am doing and I think it can be done compactly, Ill let you know if I have questions. Thank you for the advice!
This works by first having the laptop take an image and generate that into gcode instruction that can then tell the motors to move to specific cordinates on the paper and then when to move the pen up and down. The calculations are done in the universal gcode sender application, and then these instruction are sent to the arduino microcontroller where it then controls the motors with the instructions resulting in movement. This was a fun project to work on the most engineering was definitely in the 3d printed parts and deciding on materials to use!
Fix the axle on both sides. Modify the pen servo holder to a linear actuator that can lower or lift the pen from the paper. Make sure the belts are as parallel with each other as possible
I wonder if you could reduce cost even further by trying to make a custom solenoid for engaging the pen up and down instead of a servo motor.
Making the belts parallel with your axis instead of on an angle will increase your accuracy a lot. You could also put the pen in a tube to travel vertically up and down and have the servo arm drive a pin on the side of the pen up and down.
Keep at it. Even a wooden dowel would work well as a shaft, . Even better if you had a top/bottom roller that were mated with gears to provide opposing drive function, but that would add to the mechanical complexity.
At the minimum constrain the opposite side, and for added results, constrain the back of what the paper slides on to the shaft with some springs or something to make sure you get good traction.
Your pin could also stand to be transposed a little bit off axis so that the rotation results in more upward movement of the tip, and less horizontal movement of the tip. That would require the servo actively apply torque to push the tip into the paper. Conversely, just print a little channel, and put a rubber tire or whatever on the servo so it acts like a rack and pinion. Put the pen into the vertical channel, which constrains it into just moving up and down, and then the servo can push down on it as needed, though that will likely result in some slippage. This could be fixed with gear teeth or with a linkage.
I made one of these for one of my engineering classes and I would love to send you the files if you want. I used paracord as a drive belt in my design. I love the way you move the pen off the paper with another servo motor. That's a functionality that my design did not have.
Hey brotha, just commented on the short but this provided good insight for me to get some ideas. The coat hanger should work as long as you fix it on the right. Still not sure on the necessity of the servo unless you definitely want a dotter, in which case it would work better with the pen on a 1 inch horizontal lever, then drive the servo way less. This will simultaneously allow the pen to overpower the servo a few mm with the torque from being offset (should increase your success rate of pen contact) as well as allowing you to more accurately affix it to the system since the pen itself will rotate much less. Im by no means a pro but I finished mechatronics with a 100 if you have any specific questions 😎😂
Excellent! The idea of moving the pen is much better than what I am doing and I think it can be done compactly, Ill let you know if I have questions. Thank you for the advice!
that's pretty neat
How does this work what does it do? I am interested in engineering so yeah
This works by first having the laptop take an image and generate that into gcode instruction that can then tell the motors to move to specific cordinates on the paper and then when to move the pen up and down. The calculations are done in the universal gcode sender application, and then these instruction are sent to the arduino microcontroller where it then controls the motors with the instructions resulting in movement. This was a fun project to work on the most engineering was definitely in the 3d printed parts and deciding on materials to use!
Looks intriguing! Keep up the work!