So I bought such a professionally-made replacement stick for 8$ as shown above because I was curious how good the stick really was. After some tests I must say this stick is absolute shit!
1.) The range of the stick is slightly higher (
176 steps per axis) than it should be (160 to 170 steps). But that's not the real problem...
2.) Instead increasing/decreasing the +/- 88 steps one by one the program on the IC is skipping steps! When in neutral position, the x- and y-axis got the value 0. When slowly moving the stick to the right, that x-axis' value should
increase by one: 0,1,2,3,4,5,...,87,88.
But this shitty stick is skipping most of the steps. At first it increases the value by 2, afterwards the value is increased by 4!
0,2,4,6,8,10,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88. W T F ?
When moving the stick to the left it get's even a little bit weirder:
That means the real resolution is only about 50 or 52 steps / axis; and these steps are whether 2 or 4 steps worth.
3.) That replacement stick is also SLOW when making those steps. Here's a pic showing the XA and XB lines. http://i.imgur.com/BHMak.png
At the beginning, the x-axis voltage was about 2V and has been pulled to GND in an instant. Notice the long time the stick stays in neutral position.
Also notice how much freaking time it takes for the stick to make it's way from neutral position to all the way left.
You can also see the steps are made very irregularly. Most of the time nothing happens, then 2 or 4 steps are made at once in a very short period of time.
For comparison here's a pic showing how the program for the Atmel microcontroller is handling the steps:http://i.imgur.com/QfdXf.png
You can see it's much, much faster and much more regular, too.
I really don't know what the designers of the stick were thinking. Did they even test it?
With that replacement stick some special moves in Smash Brother can't be executed properly. The spin attack in Zelda OOT doesn't work, too.
If you remove all the parts on the pcb except for the potentiometer you can install an Atmel microcontroller. That will solve the problems described.
Here's a little video showing the stick skipping most of the steps: