Hot WireThe hot wire in our project is made from nichrome and when 3 amps go through the wire it heat up to about 600 degrees Fahrenheit. This allows us to cut through a foam block with ease. What is powering our wire is a mosfet being controlled by a PWM signal from an Arduino (Read more about it in “PWM Power Control”). The wire when it cut the foam make fume that are toxic and we integrate fans with filter to fix that.
It was a design challenge to secure the hotwire in the carriage and keep it powered. We decided that connecting 18 gauge power wires to alligator clips and clipping them on the hotwire the best way to secure and power the wire. Now we don't have to worry about the wire melting the solder or the carriage if it gets too hot. This solution also allows us to easily change the wire when it wears down or breaks.
The fans in our systems are radiator fans that can create strong airflow so that the fumes go through a filter instead of filling up the room with toxic fumes. These fans are powered by mosfets having pwm controlled from an Arduino(Read more about it in “PWM Power Control”). They're running a duty cycle of 30% on and 70% off this draws about 3 amps. This applies a good flow in the enclosure to pull air into the chamber but also out of the enclosure set the power supply can have air flow.
For our final iteration of this project we decided to add a little bit of pizzazz to the project. They can be very well seen in the mechanical system but we decided to also do some things for the electrical system as well. Neopixels are a great way to add some fun color to our project. To make things simpler we added a buck converter the just steps down the voltage from 12 volts to 5 to keep it stable and that powered the neopixels. The neopixels are programmed what color they are at the same rate we know that's powering the hot wire in the fan. For now neopixels are just turned to green. But getting into the electrical system that can be changed and cooler programs can be added to the neopixels can do animations.