Originally shared by Addidis no The powered hub for the pi is now powered

Originally shared by Addidis no

The powered hub for the pi is now powered from the ATX instead of a wall wart and it is now mounted to the case accessible from outside.

Dont you thing power supply would be far away from electronic items to decrease electromagnetic noise ?

Nah not too worried about it.

@Nicolas_Georgemel I’ve only had extremely noisy things like shitty fans cause stuff like this; PC power supplies are very good at not having external noise. I flip on a desk fan next to my electronics though, and instantly, my print will stop.

From an emc perspective both can be really bad. High current fast switching devices can emit a lot of noise (brushed motors can be really really bad if torque is high). But the designers of switched mode power supplies have to meet a strict set of compliance standard for the device to work near a mother board. Most of the internal parts are for filtering out noise (do not take it apart, it contains many capacitors, and disconnecting the power does not discharge the caps). A good psu is probably less noisy than your steppers by a long shot.

Side note, if you got a cheap power supply add a couple of small value caps to the dc lines. Most common mistake that the power engineers make is ignoring the esr of their capacitors, this means that some times you get a hf buzz on the line. this will cause problems for high frequency devices (for motors and relays or any other induction device it will not matter). To fix this it is really easy, add 3 caps (~100, 10, 1 uF) in parallel from power to ground on. If you still have problems wrap the wires around a ferrite (the caps will go on both sides of the wires). An untrained engineer will say just add a 200uF cap it will be better, a well trained engineer will know that each cap kills a different frequency bands.

Very good analysis !

right its an 80$ psu, it should be fine. I also just slid the psu and the ramps back to make room for the wires. :slight_smile:

DIY FTW. :wink: