That is really well made, given the technology you used. I thought about the exact same thing (except I've never seen such a small Arduino compatible board!),
That's the big one, the one I intend to use is even smaller 😉
but I wasn't able to find the 74LS00 IC in a DIP package. They have SOIC, but not SOIC to DIP adapter so I'm stuck.
The documentation mentioned that 74HC00 would also work, that's what I'm using. If I suspect that the HC vs LS is causing problems, I can easily switch it out for the 74LS00 I cannibalized from a dead old board - hence the socket.
Do you understand the purpose of the 74LS00 in this circuit? Can't the same role be fulfilled more adequately by an optocoupler? it provides true galvanic isolation from high voltage, and the logical inversion can be done either by a pull-up resistor or in software (far simpler).
Looks to me like it's mainly just abusing a NAND gate to act as an inverter, outputting logical 0 whenever input from the Arduino is 1 or vice versa. That said I am a novice at this sort of thing, so sticking with in original design until I know better.
P. S. I always expect connection problems from these dupont wires, but they have never given me any. Except when I see that the pin-tip is not shiny, I clean it up until it shines. They seem to be prone to light oxidation over time.
This is an almost new set I obtained with a Raspberry Pi electronics tutorial kit. I got that about the same time I discovered Arduino. I still love Pis for more complicated computer stuff, but for nuts and bolts I'm converted to Arduino all the way.
Have finished the hardware of the soldered version, but still need to figure out how to program this little one:
Of course the other side looks like a dogs' breakfast 😉
A passive adapter? It would only work with a dual-interface mouse (COM + PS/2), I don't have nor ever seen one. I'll much rather use a good modern optical/laser mouse.
Works just fine with my opticle ps/2 mice and usb mice with ps/2 mice adapters. Obviously you haven't been around computers that long.
That's an unnecessarily condescending comment - and too much of a generalization too. I have several such passive adapters and can assure you they do not work with my Microsoft Trackball Explorer, which is what I want to use with the PS/2-less systems too. Otherwise I wouldn't have bothered with all this work...