Hello to all. I have a couple of questions that I need help with. I have a nonlinear actuator that has a built in potentiometer that uses 5 volts into the pot to control positioning of the actuator. The actuator is simply a geared rotary actuator that operates on 12 volts. I have a Sainsmart 4 relay board to turn the motor on and will control polarity to the actuator motor to make it move cw or ccw. I am using an Arduino Uno rev3 board for the controller. I understand that the wiper on the pot will be connected to an analog input that will monitor the voltage coming out of the pot. What I need to know is how to make the connection from the Arduino to the relay board so that I may turn each relay on individually. The relay board has these connections: GND, IN1, IN2, IN3, IN4, VCC. I also need to use a 5volt signal that is connected to an external switch that becomes 5volts when switched on and o volts when switched off. The signal circuit with switch is already there. I need to know how to use this 5 volt signal so that when the arduino sees it, it will enable the relay board to turn the actuator motor to a set point and maintain that point until the 5 volt switch is turned off, at which point, the actuator motor turns back to its original position until the 5 volt switch is turned back on. Thanks to everyone for any help they can offer. New to the Arduino and very excited to start learning more about it.
Please use line breaks, your post is incredibly hard to read.
If you have to mimic the output of that potentiometer, you need to remove/disconnect it and use a DAC.
lg, couka
I apologize for the format of my post. I agree, it is very hard to read. Why do I need to use a DAC
instead of a potentiometer? The pot is being used as a reference point to turn the motor off once it
reaches it's position. The pot is physically attached to the rotary on the actuator.
I thought the potentiometer is used to control the position?
Anyways, I think you should try to explain what have and what you want to do with it again.
If you can find, include links to your actuator thing. If not take pictures and upload them.
lg, couka
What I have is a rotary actuator that has a built in potentiometer. The pot has 5 volts that come into it
and the other end is connected to ground. The wiper has a variable voltage based on position. I have
an external switch that controls a high voltage of 5 volts when switched on and when it is switched off it
shorts to ground and becomes low or 0 volts. What I am trying to do is to use the switched 5 volts to
turn
the actuator on, have it rotate to a fixed position, and stay there until that 5 volts on the switch is
switched low again manually. When the switch is turned off, I want the actuator to rotate back to its
original position and turn off. It's basically turn on a switch, the controller gets the 5 volts at which
point the actuator turns to a fixed position, using the pot to determine this position. Turn the switch off
and the actuator goes back to its original position.
Ah ok, so the potentiometer is there to determine the position, not to control it. I got that wrong. So what did you do until now. I don't see a problem with what you are trying to do.
lg, couka
Assuming the relay board is controlled by five volts and the current requirement doesn't exceed the arduino's capacity then you can directly connect data out pins to the relay board inputs. If the voltage and or current needs to be greater then you can either use individual transistors or a driver chip. The later would be my choice. There are many different types. Most are inverting with open collector outputs good to 30V or so. search
Reading the presents of 5V is easy. Run the line through a 1K resistor (not really needed, just for safety) to one of the data in lines.
For the pot I would use it in a voltage divider with a limiting resistor between it and power and then feed the wiper contact directly to one of the analog in lines.
Hope that helps
Anthony
Hi,
Can you post a link to the spec/data of your actuator please.
If the pot on you actuator outputs 0 to 5V to represent position, then you can connect the pot output to an analog input of the controller.
The gnd of the pot must be connected to gnd of the arduino, to provide a reference point.
The pot you use to set position can be a 10K pot, one end to gnd, the other to 5Vpin on arduino controller, the wiper directly to another analog input.
Your switch can be connected to a digital input of the arduino, with a 10K resistor between the digital input and gnd to ensure the input goes to gnd when the switch is open.
Can you post link to data on relay board or link to the seller and/or a picture of the board. The reason is that there are so many different arduino compatible PCBs and they are not all the same.
Thanks .. Tom.. 