Wood burning tool

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I don't have experience with making a pyro-pen, but you want to look at the specifications and make sure pic related is satisfied

also, unless you already have a PSU, you'd be better off buying a lab power supply, because PC power supplies require you to 'turn on' the power supply using a jumper on the ATX pins

Yep already have the psu (it was free) and it has a maximum of 30A output on the +5v line so 20A should be fine, the main problem im having is how to control the voltage so i can make it output 0-5V but have that controller handle the 20 amps

>>1048804
All you really need is a dual pole switch to switch the ac live and ground the PSU's on pin.

Yea I have the supply sorted, Found a few tutorials online, its pretty cool actually cause you can make a very powerful bench supply for next to nothing

>>1048811
check this out friendo

https://www.youtube.com/watch?v=IjJWWGPjc-w

as for the amps, you need to make sure your circuit is not drawing more than 20A. you can calculate this using I = V/R where R is the resistance of the burning wire.

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>>1048811
>how to control the voltage
Take a 556 or 741, wire as a pulse generator. A pot to adjust the pulse rate.

Use pulse output to gate a FET-- or several FETs in parallel-- to handle the drain of the device.

>>1048832
yep the wire should only pull about 18 amps when its 10 cm long at 5V (resistance of about 0.267 ohms)

however i would like some tips to be 5cm long, this would mean that the maximum voltage is about 2.5V which is where the voltage control comes in =]

So if i connect a pwm dc motor controller to a mosfet will that work? i can buy a 12v pwm controller on aliexpress for like $4

>>1048820
They are very convenient because PSUs are so easy to come by, and can output very high current at a few very useful voltages. The main issue you don't get with ATX power supply mods is current limiting. On a regular benchtop supply you can set it so that if it hits 200mA (or 5A, or whatever the range of the supply is) it just won't go any higher. Great for not completely ruining what you're working on if you make a mistake.

>>1048873
Yea ill probably put a 20-25A fuse in there as a backup for any mistakes but im thinking im just gunna have to bite the $150 bullet and buy a 20 amp variable power supply because then i can at least use it for other projects as well.

Go here:
http://frozenburritosnightly.com/pcpowersupply.html

He's controlling the 12v but you can do the 5v instead.

>>1048799
Just use a variac feeding a step-down transformer*. I'm assuming the temp control is purely manual, so anything more than watching the work and tweaking a knob isn't needed.

*Two winding, 120V to 6V. Provides higher current and isolation from the line voltage source.

Thats now a bad idea actually, iv managed to book some time with one of the electronic lecturers at uni today so ill ask him about it and see what he says. If i have any success ill post a diagram later today