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Topic: Servo and Linear Actuator use with Arduino Uno (Read 1 time) previous topic - next topic

khow09

Feb 07, 2014, 06:04 am Last Edit: Feb 07, 2014, 06:16 am by khow09 Reason: 1
First off I apologize if this may be a bit repetitive, but I've been researching for a couple of weeks and can't seem to find a clear solution. I'm from more of a mechanical background so apologies if I get the terminology a bit sideways.

So my setup is to use a linear actuator and a servo in a consecutive manner where the actuator will extend a determined distance, and then the servo will rotate a finite amount. What I am struggling to figure out is how to construct/design the power supply I need to make the system work. This will all be inevitably hooked to a 120 volt wall outlet so batteries won't be an option. Below are the the links to the actuator and the servo I have chosen. If you know of other actuators and servos please feel free to let me know. I am bound to specific ones though due to force and torque outputs.

Actuator:
http://store.firgelli.com/L16_Linear_Actuators_p/l16-p.htm
Servo:
https://www.sparkfun.com/products/11881

I understand that the arduino only has the output capacity of 5V and something like 40ma at the pins. In order to reach the needed applied force on the actuator, I need to hook it to a 12 volt source with a current to match. So my questions are as follows:

1)Will a motor shield work in this case to supply voltage and current to the servo and actuator? Would this allow me to skip a power supply all together?
2)If I do go a power supply route what exactly is needed? I have limited knowledge of electrical components and determining the necessary parts has me quite confused.

I appreciate any help! I'm super excited to start learning the code once I figure out my needed components.

jremington

#1
Feb 07, 2014, 06:25 am Last Edit: Feb 07, 2014, 06:32 am by jremington Reason: 1
The servo requires 5 or 6 volts at at least 1 ampere current (probably more if there is a significant load) while the actuator requires 12 V at 0.6 amps to deliver its rated force. If you want both to work at the rated torque or force then you need two different power supplies, plus a motor shield or motor driver board for the linear actuator. The Arduino should never be used to power a motor, but the pins are used to control the servo and the motor driver.

The actuator will probably work on 6 V, but it would deliver half the rated force or less. If that is OK you could use one 6V power supply rated at 2 amperes continuous current for both.

For connecting servos and the Arduino see the attached diagram, drawn by another forum member. For connecting the actuator, refer to the documentation for the motor driver you choose. I use and prefer the boards from Pololu, who also provide excellent support for their products. This one will work for your actuator: http://www.pololu.com/product/2136

Be sure to connect the grounds of all power supplies and the Arduino together.

khow09

#2
Feb 07, 2014, 06:43 am Last Edit: Feb 07, 2014, 06:46 am by khow09 Reason: 1

The servo requires 5 or 6 volts at at least 1 ampere current (probably more if there is a significant load) while the actuator requires 12 V at 0.6 amps to deliver its rated force. If you want both to work at the rated torque or force then you need two different power supplies, plus a motor shield or motor driver board for the linear actuator. The Arduino should never be used to power a motor, but the pins can be used to control motor drivers.

The actuator will probably work on 6 V, but it would deliver half the rated force or less. If that is OK you could use one 6V power supply rated at 2 amperes continuous current for both.

For connecting servos and the Arduino see the attached diagram, drawn by another forum member. For connecting the actuator, refer to the documentation for the motor driver you choose. I use and prefer the boards from Pololu, who also provide excellent support for their products. This one will work for your actuator: http://www.pololu.com/product/2136

Be sure to connect the grounds of all power supplies and the Arduino together.


Thanks for the reply!

Ive been browsing digikey and noticed they have power supplys that supply current/voltage via 2 channels. Am I on the right track looking at something like this?  http://www.digikey.com/product-detail/en/KMT40-51212/285-1777-ND/1827710 Or when you say two, it needs to be two separate units?

jremington

You can certainly buy dual power supplies and one that would provide 5 (or 6) V and 12V, each at 1 ampere or greater, would be ideal. You might even find a "power brick" for an old LCD monitor or laptop that provides both voltages -- I happen to have one like that.

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