SparkFun Forums

[k2np818]

I have developed a lift using a servo motor via on a Redboard.
I need to a control point to tell me when the lift is in the right position which in turn will turn "off" the servo.

(the program will turn the servo until the sensor indicates the lift is in the right position. When in the right position
the program will then turn off the servo.)


can anyone recommend the right type of sensor to use and where I could find it (to order) on the Sparkfun site?
or can you point in the right direction if this is not the right place to post.
:think:
Thanks:
Ken

[Mee_n_Mac]

There are multiple ways you could go. A simple mechanical microswitch would be one. Another would be a Hall effect sensor (or even a reed switch) and a magnet on the "lift". And yet another would be a short range proximity sensor that "sees" when the lift is in place. That could also be a continuously sensed beam that is interrupted when some part of the lift blocks the beam. The latter has the feature that if the sensor fails, it'll likely fail safe and stop the lift. Some of the other IR sensors can tell you a range to the lift and thus allow software to slow the servo before getting to the stop point.
https://www.sparkfun.com/products/9312
https://www.sparkfun.com/products/8642
https://www.sparkfun.com/products/246
https://www.sparkfun.com/products/12728
https://www.sparkfun.com/products/9299

[k2np818]

this will work just fine for the lift. thanks for the prompt response.
Photo Interrupter - GP1A57HRJ00F

I am following the crawl, walk, run approach here....
before I purchase the sensors and other stuff.....

I have another question... purchased a 31425CR (HSR-1425CR servo) continuous rotation.
The objective is use this to wench the lift up and down.
In testing the servo worked great in one direction and did a test to get it rotate in the other direction.
It seemed to work once but I have not been able to repeat it.
Do not know what I am doing wrong. I thought I could program it to from 0 to 180 and then 180 to 0 for reverse direction.

Another set of sensors will be used it indicate go ahead and lift up .... another sensor to go ahead and lift down (reserve).

any assistance you can provide would be appreciated.

Thanks:
Ken

[Mee_n_Mac]

According to the description I could find that servo should go in both directions.

From Servo City ...
Introducing the all new HSR-1425CR Continuous Rotation servo. If you are looking for a servo to pan or tilt your small camera or sensor multiple turns, this is the servo you need. If you are looking for a servo to power the wheels on your small robot, this is the servo you need. Fully proportional speed forward and reverse for precise movements. The potentiometer has been taken out and the dead-band increased to eliminate “creep” that occurs in many other servos that are modified for continuous rotation. Dual ball bearings on the output shaft ensure long lasting performance.

I've not used one but I thought a 1 ms PW got you full speed in 1 direction and a 2 ms PW got you full speed in the other directions. Not sure where it's going bad for you. Given it worked once, I'd triple check the connections.

[k2np818]

ok thanks for the tip ... will double check things and let you know....

[k2np818]

yep working fine thanks for the assistance......