Hi everyone, I'm pretty new to Arduino and anxiously discovering all it has to offer.
I have a basic idea on how to lay out my projects but hit a wall when it comes to choosing the right components (and doing so safely when it comes to things that plug into the wall).
What I'm trying to do is control a simple 12v linear actuator (no built in potentiometer) with my Arduino UNO.
See the attached image for visuals! -> http://i.imgur.com/iEM3coK.jpg
The 12v linear actuator is rated for 200lbs and it came with it's own control box and basic remote that plugs into the wall.
Instead of worrying about an H bridge or dc motor shield, I figure I can make use of the control box as the power supply, and hack apart the basic remote control and interface it with the UNO.
Where I hit a wall is how to rig up the circuit where the UNO can send the HIGH/LOW (UP/DOWN) commands to the actuator control box through the remote control input wires. The remote is very simple and the up/down actuation comes from just reversing the actuator motor's polarity.
The remote has 3 wires: UP/DOWN/COMMON. I believe the common wire is the ground? Touching the UP wire to the COMMON completes the switch circuit and sends a command to the control box to move the actuator UP. DOWN wire to COMMON wire moves the actuator down. I believe there might be end-stop switches inside the actuator itself because it automatically stops the motor when fully extended or retracted.
When plugged in, the voltage across the remote's switch terminals is 17.3v.
Do I need a 2 channel 5v relay? Two single channel 5v relays? Two Transistors, and if so which specs? Diodes/Resistors? Any guidance on parts I need or circuit wiring suggestions is very much appreciated.
Budget isn't really a problem for the minor components.
The ultimate goal is to define the actuator's range in Arduino code (It extends 6" inches total) and make "presets" for different lengths of extension.
For example:
- UP Button (hold it down)
- DOWN Button (hold it down)
- PRESET 1: Fully Extended
- PRESET 2: Fully Retracted
- PRESET 3: 25% Extended
- PRESET 4: 50% Extended
- Etc...
Since there's no potentiometer, should I add one into the mix (and how would one do that)? If so what is the best way to wire and code that in? Or could I 'guess' the position of the actuator by timing it (ie, 5 seconds of activation = 50% Extended)? I could see the latter being a problem if UP/DOWN buttons were used for manual positioning.
Right now I just want to control it using code...eventually I would like to have both physical switches AND 'digital' switches (for example from a web browser) that would control the presets.
Again I appreciate any help or criticisms...thank you!