Frivolous Engineering
© 2016 Frivolous Engineering
Inside The Useless Machine
The Useless Machine consists of a actuator driven by a DC geared motor, two switches and a battery pack (not shown). Most small DC motors are high speed, low torque and won't have enough power to flip the toggle switch.  So a GEAR system is needed to REDUCE the speed and INCREASE the torque. Two kinds of switches are used in the Useless Machine: a TOGGLE SWITCH on top and hidden inside the machine is a LIMIT SWITCH. A good explanation on switches, poles & throws can be found here. The Toggle Switch used in the Useless Machine is a Double-Pole, Double-Throw (DPDT). The Limit Switch is a Double-Pole, Single-Throw (DPST) and it has a lever on it. The Limit Switch is wired up so that it's normally CLOSED (turned ON). When anything pushes the lever, the switch OPENS (turns off). This is opposite to how most switches work.
The Useless Machine Circuit uses a variation of the standard DC Motor Reversing Circuit as shown in the diagram to the left. Flipping the Toggle reverses the current flow, causing the DC Motor to reverse direction.
The Useless Machine's circuit has a limit switch added to one of the cross-over wires.
When the machine is "OFF", the actuator is in the home position and is depressing the limit switch. The Limit Switch is OPEN, preventing any current from flowing. Therefore the machine is off.
When a person flips the toggle switch, it turns on the machine allowing current to flow through the motor causing it to turn counter-clockwise. The red lines in the diagram show the path and direction of the current.
When the actuator flips the toggle switch back, it reverses the current going to the motor causing the motor to rotate clock-wise. Because the limit switch isn’t depressed at this point in the machine’s cycle, it’s closed (ON) allowing the motor to run and the actuator to retract back into the box.
The red lines in the diagram show the path and direction of the current. When the actuator hits the limit switch lever the machine turns off. The toggle switch will turn the machine ON, but it's the Limit Switch that turns the machine OFF.
For visual bling and to indicate the direction the motor is turning, Red & Green LED’s and resistors have been added. LED's need the current to be flowing in a particular direction, so if you put two together in parallel, but reversed polarity, only one LED will light up at a time.
Copyright©2016 Frivolous Engineering
Inside The Useless Machine
The Useless Machine consists of a actuator driven by a DC geared motor, two switches and a battery pack (not shown).
The Useless Machine Circuit uses a variation of the standard DC Motor Reversing Circuit as shown above. Flipping the Toggle reverses the current flow, causing the DC Motor to reverse direction.
The Useless Machine's circuit has a limit switch added to one of the cross- over wires.
When the machine is "OFF", the actuator is in the home position and is depressing the limit switch. The Limit Switch is OPEN, preventing any current from flowing. Therefore the motor is off.
When a person flips the toggle switch, it turns on the machine allowing current to flow through the motor causing it to turn counter- clockwise. The red lines in the diagram show the path and direction of the current.
When the actuator flips the toggle switch back, it reverses the current going to the motor causing the motor to rotate clock-wise.
Because the limit switch isn’t depressed at this point in the machine’s cycle it’s closed (ON) allowing the motor to run and the actuator to retract back into the box. The red lines in the diagram show the path and direction of the current. When the actuator hits the limit switch lever the machine turns off. The toggle switch will turn the machine ON, but it's the Limit Switch that turns the machine OFF.
For visual bling and to indicate the direction the motor is turning, Red & Green LED’s and resistors have been added. LED's need the current to be flowing in a particular direction, so if you put two together in parallel, but reversed polarity, only one LED will light up at a time.
Most small DC motors are high speed, low torque and won't have enough power to flip the toggle switch.  So a GEAR system is needed to REDUCE the speed and INCREASE the torque. Two kinds of switches are used in the Useless Machine: a TOGGLE SWITCH on top and hidden inside the machine is a LIMIT SWITCH. A good explanation on switches, poles & throws can be found here. The Toggle Switch used in the Useless Machine is a Double-Pole, Double-Throw (DPDT) switch. The other switch is a LIMIT SWITCH with a lever on it. It's a Double-Pole, Single-Throw (DPST) switch.  The Limit Switch is wired up so that it's normally CLOSED (turned ON). When anything pushes the lever, the switch OPENS (turns off). This is opposite to how most switches work.
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