A little over two weeks ago I purchased enough parts to make my own robotic arm. I had one big problem though which was the irritating power supply wire trailing across my desk, it was neither safe or practical. So for the past four evenings I have been putting together a solution I have decided to call the Power Distribution Unit (PDU).
I now have a cable running under my desk with one end connected to the PSU, the opposite end has a DC jack which plugs into the PDU which is screwed to the underside of my desk. now i only need a short cable to supply the arm.
The setup is rather simple, there are two rails +V and -V, there are two breaks in the +V rail to allow the use of a panel mounted fuse and switch, after that there is a 5A Resettable fuse and a 470uF Capacitor for smoothing out any dodgy feedback.
Here is a rough diagram showing the layout of the circuit.
(+V)----(Switch)----(8A panel fuse)----(5A Reset Fuse)----(470uF Cap)----(Plugs)
(-V)---------------------------------------------------------------------------------(Plugs)
I am using two sets of fuses for several reasons, The PSU supplying the power has its own overload protection making it a little pointless but I also have the option of powering the PDU with a battery if I want to, everything in the PDU has been tested to supply up to 5A and I do not want it going beyond that, this is where the resettable fuse comes in, should I exceed 5A for a short period it will temporally break the circuit unlike the fuse which is set at 8A and provides protection against accidental short circuits. I’m not entirely certain how fast a resettable fuse reacts to 8A so the standard fuse has the job of breaking the circuit quickly should it happen. I’m a great fan of redundant circuits so I like to have more than one fail safe just in case of unforeseen circumstances.
this is what I hope to be the first in several generations of PDUs ill make, I have already decided on several improvements and upgrades, the most important one being a by passable Voltage regulation circuit so I can supply a set voltage from a battery or from my PSU.
Please forgive any obvious flaws as I’m entirely self taught, I’m sure there are many flaws in the circuit itself.