The Ben Heck Show

Super Glue Gun: Hall Effect Sensor Hysteria! (5) (7x24)

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Today the team is getting back to the super glue gun build. Previously, they worked on the extruder, the hot and triac control, and picked a microcontroller. Now it’s time to take the foam mock up they worked on for the gun and design a PCB that will inside of the handle. Felix walks through the H-bridge testing. The H-bridge controls the motor. The input takes in 12 volts to drive the motor and the control pins make the circuit switch the terminals that are connected to the motor. In other words, the microcontroller allows the pins to switch between positive and ground. After the terminals of the motor driver are connected to the motor, Felix plugs it in to give the switch some power to turn on. He does a final test to make sure the circuit works, turning it in each direction. Ben cuts a pair of PCBs in the shape of a gun handle. He’s designing a PCB based off their foam core design, he’ll then design a 3D printed part around the PCB. He uses the cut PCB to consider placement of the hall effect sensors, the power supply, the microcontroller op-amp triac, and the h-bridge, to fit within a handle will contain a plug at the bottom for AC power. Felix picked up some regulator packages for Ben to take apart piece by piece to see what’s on them. The packages take in 110 VAC and spit out 12 and 5 volts DC. One such piece hooked up to the AC lines is a surface mount chip known as a bridge rectifier. A bridge rectifier is where you take four diodes and you use that to convert an AC voltage to a DC voltage. The other side of the bridge rectifier is still going to be 120 volts but it’ll be DC. He removes parts of the board and puts it onto his board bit by bit.