Let's check out

Let's check out how a couple of relays get you on off and up down control of a linear actuator using only two wires. And the key to this is relays. A type of device that takes switching voltage in on one side and changes the common terminal between normally open and normally closed on the other when the signal on A1 A2 changes. To be able to have direction switching and on off control, we need two relays for this project. Next, let's start by putting the linear actuator wires on the two common terminals of our relays because they're the ones that need to switch between 0 volts DC and 12 volts DC. And it's important that one relay has normally open 0 volts DC and the other has normally closed 0 volts DC, so they're opposite. And A1 on both relays can be 0 volts DC. Next, we can fill in all the spots that need switching and on off signal, which is going to be 12 volts when we want this thing turning in either direction and 0 volts when we don't want it turning at all. And for that reason, we can wire it to the other normally closed, normally open terminal. Lastly, we can wire the direction command into the remaining A2 terminal of both relays. The direction command (off/0 VDC) will not turn at all unless the enable command (12 VDC/open wire) is on. But when it is on, it'll switch directions based on the direction command that activates the relay. Relay logic is really cool and kind of the origin of all control automation. And if you thought that was cool, make sure to follow along because we're doing a lot more cool stuff on this build. And the most important part is that it works. You can see the up and down switch changes the actual state of the relays by the LEDs on them, but it won't start turning until we turn the on switch to on. And then once it's on, we can change the direction with the up down switch, but it won't do anything unless the on off switch is enabled. Relay logic is really cool and kind of the origin of all control automation.