Can I wire the green ground wire from my Happ trackball to the GND on my iPac2?

[P-chan]

Or does it need a separate ground?

[PL1]

Or does it need a separate ground?

The green wires with the ring terminal usually connect to frame ground, but IPac ground should be OK for bleeding off any static charges generated by the ball rolling on the steel rollers.


Scott

[bobbyb13]

I imagine Scott is correct (as per usual!) but I am always hesitant to mix source ground (and therefore local cabinet static possibilities) with logic ground myself.

Give that static electricity a fast track to your local power grid (or the earth under your house!)

I may be neurotic, but I like a separate bus bar or common stud for source and friction/static grounds to bond to (like cabinets in the old days I suppose.)

[jennifer]

I cant imagine steel on steel would generate much ESD, But you want to take into account some electronics can be damaged by static charges, Perhaps check out what chips you are dealing with first.

[PL1]

I cant imagine steel on steel would generate much ESD, But you want to take into account some electronics can be damaged by static charges, Perhaps check out what chips you are dealing with first.

Rapidly rolling an acrylic trackball on steel rollers will generate a considerable static charge due to the triboelectric effect.

Remember, that roller ball could charge up to almost 100kV.  Very high peak transient current surges can develop from that discharge into sensitive TLL and more so CMOS chips and cause permanent damage.

At least one BYOAC'er forgot to ground the green wires and generated enough static charge to fry their optical (mouse) encoder.
- Best practice is to connect the green wires to frame ground.
- At an absolute minimum connect them to encoder ground and hope that doesn't cause premature failure in the encoder's ICs.

Parting thought from BobA:

If it was meant to tie into the logic ground I do not think that they would have supplied the separate green wire for the protective ground.

Scott

[bobbyb13]

I cant imagine steel on steel would generate much ESD, But you want to take into account some electronics can be damaged by static charges, Perhaps check out what chips you are dealing with first.

Right?!
My experience of living in cold climes previously tells me that certain places are more likely to build static charge through friction of almost anything (not only just wax and wool or balloons and hair.)

So depending on your local climate yrmv.

[P-chan]

 Thanks everyone! The last point from BobA makes the most sense, thanks Scott.

[RandyT]

- At an absolute minimum connect them to encoder ground and hope that doesn't cause premature failure in the encoder's ICs.

I just wouldn't connect it, if this were the only option.  Like BobA stated, it wouldn't be separate if it wasn't meant to be.  Better to need to clean the unit more often.  It's really the only reason for the ground wire.  Static attracts hair, lint dust, etc.  This mixes with the human grease on the ball and turns to crud, which is deposited to the rollers and then interferes with the TB's operation.  If there were any significant charge in the ball, it would probably be better to allow it to dissipate naturally, or through player contact, than through the ground path of the electronics.

I think the case of someone nuking their optics PCBs is bit of a "wives tale".  The possibility of it happening is remote at best.  Think of all the pre-built consumer panels with trackballs out there, with the only wire exiting them being the USB cable. 

[PL1]

I think the case of someone nuking their optics PCBs is bit of a "wives tale".

Can't find it at this time, but I definitely remember a thread where a guy fried an optical board in an ungrounded HAPP trackball.
- IIRC, after some vigorous gameplay he heard a static discharge "pop", one axis stopped working, and he had to replace the optical board.

The possibility of it happening is remote at best.

Remote, but possible.


Scott

[bobbyb13]

If you have life insurance, home insurance, health insurance, car insurance, etc...

Then a few feet of green 12g wire and a ring terminal sure is cheap cabinet insurance!