Component Question

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#1

Hello all, programming my first robot for an engineering class. We have a cortex micro controller that we would like to be able to open and close a switch. What I mean by that is we have a battery, and a load. We would like to be able to add a switch in between the battery and load that we could turn on and off with the cortex. A friend recommended using a motor controller, but we don’t need all the fine-tuning/variable speeds, just a simple on and off. Does such a component exist?

Thanks in advance

#2

Hi there,

I don’t believe that there is a VEX component to do what you want to, but what you are looking for would be a BJT or Bipolar Junction Transistor. One guide is here but you can most likely find better resources through Google.

#3

Thank you for your reply… would you know where could I order one that would take the PWM cable?

#4

Hookup wire and a breadboard would be your best bet for prototyping

#5

What about a good old fashioned relay?

#6

Do you have a link to a pre-made one, or is that a component I would have to breadboard?

#7

There are plenty of non-vex options, what’s the battery and what’s the load. ie. how much current at what voltage are you trying to control?

Perhaps something like this would switch up to 10A and could be controlled from a cortex digital port.
http://www.pololu.com/product/2480

#8

YES! That is exactly what I’m looking for. We’re using a 24V battery connected to an 8W solenoid (rated for 24V) and we would like to open and close it with a pwm cable to the Cortex. Also, could you supply some ROBOTC code as to how exactly we would talk to the relay? (e.g. dgtl[port1] = 1)

Thanks again for your help.

#9

To clarify:

We need something like above, but compatible with a 24V battery.

#10