This classic Cadillac sports car turn custom couch centre piece has a surprise hidden inside its trunk. With a push of a single button, the trunk magically pops open and a bar arises from within. This show stopping effect is made possible through the use of FIRGELLI Automations wide range of electro-mechanical products.
Firstly, the opening of the trunk and the rising of the bar are accomplished by making use of two FIRGELLI Automations Linear Actuators that are connected to run in tandem or one after the other. This is done by using four Single Pole Double Throw (SPDT) Relays and two External Limit Switches. While the connection of the SPDT relays to the linear actuators and the power supply are done identically to how you would typically connect them; the connection of the relay coils are done differently. Instead, you will connect one limit switch to the coil of the relay that will cause the first moving actuator to retract, which in this example is the trunk actuator. Then you will connect the second limit switch to the coil of the relay that cause the second actuator to extend, which in this example is the bar actuator. The other two coils are connected normally as you see below.
The limit switch connected to the second actuator (SW1 in the diagram above) is positioned to where it is closed when the first actuator is fully extended. This will then allow the second actuator to start moving after the first actuator is stopped. The other limit switch (SW2) is positioned to where it is closed when the second actuator is fully retracted. This allows the second actuator to move first when the operation is reversed, i.e., hiding the bar back inside of the trunk. For this application, you will need to remove the diodes from these two limit switches. This is because the diodes are there to block current flow in one direction, which is typically needed when limiting the stroke of the actuator; but is a hinderance in this use case. If you still wanted to limit the stroke of the actuators as well, you will need other limit switches, with the diodes still attached, and connect them as you would normally do. If you would like to learn how to make use of our External Limit Switches in this way, check this blog here.
Finally, for this awesome show piece, the designers did not settle for choosing between a rocker switch or a 2 channel remote control, instead they chose both. This requires additional diodes to connect the coils of the relays to both the control board of the remote control system and the rocker switch. You can find out how to do this for yourself by reading this tutorial which shows you the alternative methods of connecting multiple remotes and switches to control a single actuator. For this application, it is recommended to use a sustaining switch or remote over a momentary one.
