Wednesday, April 9, 2014

Gnd 強化: Reinforcing Ground Line


  • Thick and big ground is essential in building systems with lots of current.
  • Anodized aluminium is good because its surface is not conductive, its electrical conductivity is good (almost 60% of copper) and cheaper than copper.


Ground reinforcement. The controller, arduino, does not exert much power and the current is not that much compared to the line from the TLC5940 modules to the power module. This might cause small impedance problem  and voltage drop, but as a practice, large conductor was distributed over the system. 


Soldering aluminium frame is not easy. Instead, the ground wire is attached to the frame using a pair of volt and nut. 

緑色の線が 2.0 mm^2 のアース線。

This implementation is kind of sloppy, because usually woody frame should shield ground to avoid occasional short circuit during wiring. (Exposed copper wire is a killer to the whole system.)

ここをちゃんとアースしたとして、電源モジュールからATX電源までは 20cm 程の割と細い線でつながっている。ここも一応太くしておいた方がいいんだけれども、というかあんな細い線に 18A も流せるようによくなってるなという話。その辺の電流変化はハードディスクとかデバイスで吸収することになっているのだろうか。いくら電源がよくても、ケーブルが細いんじゃ話にならないと思う。

My question: My ATX power source says it can screw 18A of 12V with 1 wire, and there are four outputs that has the same capability. 20cm is long enough to cause drop down when 18A current is flowing through the line. Is there any magic to compensate this voltage drop, or computer devices are not asking power that changes drastically?

やはりATX電源ではなく専用の安定化電源を買うか。24V の方が電流が少なくなる=電圧降下の少なくなる。

One option is to use 24V power source instead of 12V, which halves the total current and thus the voltage drop.