linear actuator

Hi guys

i have looked through the forums but could not find specifically what i am looking to do so appologies if it has been covered before (there is allot to go through), i am ok with electronics etc but trying to understand them a bit better by doing this. put simply i have a 36v actuator that i wish to extend when the pc is booting and the retract when it is shut down, is it possible to have it kick in once the 5v usb on the machine becomes active and then send the close signal when the current has gone? i have seen 36v relays

(http://www.ebay.co.uk/itm/IACS-4-Channel-Relay-Board-SE-3V-5V-9V-12V-24V-36V-48V-DC-4CH-TTL-10A-Arduino-IO-/180949396128?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2a216caaa0)

is this possible to do (i am assuming it will need it's own power suply to send the signal once power is lost) or can it be done via a script when the pc shuts down? is this a simple thing or am i way off the ball here, sorry if they seem stupid questions

hand holding and baby steps with pretty pictures are most welcome

thanks in advance

Assuming the USB comes on when you boot the PC, this can be used to turn on external power to the Arduino and its first task is to extend the actuator until it reads the limit switch.

When the PC turns off, the arduino retracts the actuator until it reaches the other limit switch. With a little bit of thinking the power can also be turned off to the Arduino.

You will need four relays for the actuator as you need to reverse the polarity and need to connect both +&- of the 36v supply.

Weedpharma

thank you for the reply

so the 4 channel relay i found on ebay should be sufficient along with a standard uno, it seems prety straight forward but wasn't sure about the board as i have only played with the basic micro up till now.

thanks

As the relays will only have one changeover each you will need to treat two relays as one double pole relay. IE, treat relay 1&2 as one relay and 3&4 as another.

Connect +36v to common of relay 1, Gnd to common of relay 2. Connect relay 3&4 in reverse of this.

When you operate relay 1&2 you feed one polarity to the motor. When you operate relay 3&4 you feed the opposite polarity.

Make sure your program does not have any combination of relay outputs that short out the supply or you will destroy your relays!! Make sure you use a correctly rated fuse.

Weedpharma

thanks :) got them on order, i will have an external power on the board so it is always on, but can you direct me to an area that describes how to get it to detect the 5v from the usb to operate pins and the lack of a 5v signal to operate the 2nd set. i get the fundimentals but think i am confusing myself as i am only just getting in to the electronics side of things.

Simply get a USB cable and cut the end off. Connect the Gnd to Gnd and 5v to an input pin that has been tied to Gnd with a 10k resistor.

When the USB is turned on, the arduino detects a high on the input and drives the actuator until it reaches the out limit switch. Keep monitoring the USB until it goes low then drive the actuator back until it reaches the in limit switch.

Weedpharma

Make sure your program does not have any combination of relay outputs that short out the supply or you will destroy your relays!!

Relay setup where one does not have to worry about shorting the relays out.

reversemotor.jpg

thanks guys your awesome, think I have got the jist and will give it a whirl.

thanks again