Controlling travel of 12v actuators

Thread Starter

34ford454

Joined Feb 16, 2018
12
I have a Gama RF340-4PR-ASL that has worked flawlessly for many years on a custom car. The functions are to raise the top and hood. What I want to do now is to stop the travel of the actuators at exactly (within 1 Inch) at a pre-determined position. I know that the actuators can individually be adjusted, but I want to do this electronically so I can handle the actuator lift with my existing system. I also have these actuators installed that would be an absolute bear to remove to reset their individual travel. Does anyone know of a method and parts that I can add to this system. I have 6 different actuators; all different required lengths. I don’t have the ability due to space for positioning of standard type limit switch which would be the perfect approach. Anyone have any suggestions using total electronics to accomplish this. I have purchased the Chinese type timers, etc., and they are a total waste of money and time.
Thanks
Oren Summer
 

MisterBill2

Joined Jan 23, 2018
3,996
I am not familiar with that specific model of actuator device, but I will presume that it is a linear motion device with an electric motor drive. I am also going to guess that it has some sort of internal system to operate limit switches to stop it at the desired point in each direction of travel. Timers of even the best kind will not work with such an actuator because the speed is dependent on load and voltage and probably temperature as well.That leaves sensing position, either internally or externally, as the alternative. An encoder on the motor shaft would be the first choice, but if it is not there already it is probably not practical. A second option is a package often called a "string pot", which is a potentiometer with a spool of thin cable and a return spring, where the "string" is pulled out by the linear motion to be measured. These devices come in all grades, from consumer entertainment applications to position measurement in aircraft. They can be coupled to either an analog input of a computer system or to a comparator circuit to provide on/off control to whatever is needed. They can provide long life and good repeatability. So a string pot may be what you need for monitor and control. There are many brands and most companies are very happy to provide application suggestions on how to best use them.
 

shortbus

Joined Sep 30, 2009
7,077
I don’t have the ability due to space for positioning of standard type limit switch which would be the perfect approach.
How about a "photo interrupter" working at the hinge point? The interrupter would the control the relay. The interrupters are small and there are many to choose from, just one source for them; https://www.digikey.com/products/en/sensors-transducers/optical-sensors-photointerrupters-slot-type-logic-output/547

Or you could consider reed switches and a magnet. The magnet would get epoxyed to the moving part and the reed switch to the car body, https://en.wikipedia.org/wiki/Reed_switch

You say the system "has worked flawlessly for years", what changed that it isn't now?
 
Last edited:

MisterBill2

Joined Jan 23, 2018
3,996
How about a "photo interrupter" working at the hinge point? The interrupter would the control the relay. The interrupters are small and there are many to choose from, just one source for them; https://www.digikey.com/products/en/sensors-transducers/optical-sensors-photointerrupters-slot-type-logic-output/547

You say the system "has worked flawlessly for years", what changed that it isn't now?
Usually, when a system that has been working perfectly needs to be changed it is either because the requirements have changed, or new requirements are different. All sorts of external things can change. In this case the vehicle may have become a show car instead of a driving car.
 

Thread Starter

34ford454

Joined Feb 16, 2018
12
I am not familiar with that specific model of actuator device, but I will presume that it is a linear motion device with an electric motor drive. I am also going to guess that it has some sort of internal system to operate limit switches to stop it at the desired point in each direction of travel. Timers of even the best kind will not work with such an actuator because the speed is dependent on load and voltage and probably temperature as well.That leaves sensing position, either internally or externally, as the alternative. An encoder on the motor shaft would be the first choice, but if it is not there already it is probably not practical. A second option is a package often called a "string pot", which is a potentiometer with a spool of thin cable and a return spring, where the "string" is pulled out by the linear motion to be measured. These devices come in all grades, from consumer entertainment applications to position measurement in aircraft. They can be coupled to either an analog input of a computer system or to a comparator circuit to provide on/off control to whatever is needed. They can provide long life and good repeatability. So a string pot may be what you need for monitor and control. There are many brands and most companies are very happy to provide application suggestions on how to best use them.
thanks, I have not heard of this device.
 

Thread Starter

34ford454

Joined Feb 16, 2018
12
How about a "photo interrupter" working at the hinge point? The interrupter would the control the relay. The interrupters are small and there are many to choose from, just one source for them; https://www.digikey.com/products/en/sensors-transducers/optical-sensors-photointerrupters-slot-type-logic-output/547

Or you could consider reed switches and a magnet. The magnet would get epoxyed to the moving part and the reed switch to the car body, https://en.wikipedia.org/wiki/Reed_switch

You say the system "has worked flawlessly for years", what changed that it isn't now?
I have purchased these and have not tried them but a good idea.
 
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