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kill(ing) machine (tiny little vampire insects not humans) hot smiley

Posted by terramir 
kill(ing) machine (tiny little vampire insects not humans) hot smiley
May 31, 2017 01:26PM
OK, here's the scenario;

use the 3D printer to print the plastic housing, basically it's an air heating machine.
use a 12ft 4inch (~100mm) drying hose to suck the hot air back in. use those aluminum bubble sun blockers for the car (sew em or velcro them together as a tented area) like around the bed. use an arduino to switch the heating elements on and off. use temp sensors like the one in the buda to measure the exit and intake temp as well as like one to put some where in the things to be heated. goal is 120-140 degrees F, so 48 to 60 degrees Celcius. for like two hours that should eradicate the critters.
I choose 2x 200W 12V modules as well as 4x 12V 50W modules, because the power draw can be like 3x in the beginning I figured the start-up sequences have to be on a delay first 1 200W modules then a minute later the second 200W module then the 4x50 watt modules one at a time.
figure I would need either one really hefty pc psu or two in parallel handling one 200 W one each and 2 50 Watt ones each. I know trying to use psu's in series won't work but in parallel they should.

three things I need help with:
1. Mosfet selection since the transient spike might be 50 amps for the bigger modules.
only gonna bang on and off.
2. resistor selection for the temp probe circuits because were not using reprap temperature ranges the 4.7k resistors used in out electronics are designed for a 180C - 260C range of detection what resistors should I choose for a 45C- 75C range.
3. in the future after this first design I might want to change it 110V heaters and these ptc heaters can take AC. then I won't need these PC PSU's but I will need SSR's by then I will have an exact idea of the power needed to create the warmth I need. and I'll be able to go with one or two ptc modules. (maybe two to reduce the grid spikes). what kind of transistor would you recommend to power on(ehh turn on the switching voltage) one of those ssr's?
feel free to chime in folks will be using one of those pro mini clones for the computing they can be used just like a regular arduino.

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