Re: “We have always had ESD protection in Smart Ports. The issue has not been ESD protection as much as ESD generation.”
Our teams (mostly our volunteer parents/mentors) spent thousands of dollars on new brains and anti-static tiles. Last season we took every possible precaution and because of the pandemic only competed in LRT/LRS competition on our own field. The best we were able to do is fry ONLY 4 ports on a brand new brain. This came out of nowhere, as we were practicing for skills. It also happened in the middle of a match when our robot lost a drive motor. Symptoms always the same for us. Motor stops responding. First instinct is to panic. Second to blame the programmer. Third to blame anyone who did not tighten a shaft collar and let the shaft come out. Fourth to replace the motor, has to be it right? Then cynicism steps in, panic moves to the side and experience whispers “it is always a dead port on the brain you bozo”. The port is blinking a faint red. We already have a test motor just for that. It is labeled “test motor” so we know it is a good one. Plug it in, it also blinks - we know port on the brain is dead. Move to a different port, rename/reprogram, go back to what you were doing before. A frustrating waste. It is always the TI RS-485 transceiver chip on the brain that burns, not the one inside the motor. For us at least it is. We stopped mentioning it because invariably the answer is the same. Well you did not spray with antistatic. Well your room is too dry, you did not use a humidifier. Well you did not wear your antistatic bracelet, well you did not touch a grounded piece of metal - the field perimeter is not grounded you bozo. Well you are wearing socks - get rid of the socks, well your room has carpet - get rid of the carpet, well do this don’t do that. And now “We have always had ESD protection in Smart Ports”. These devices are supposed to handle the harsh conditions of robot competitions and constantly assuming teams did something wrong because ports on a $250 device burn or brains turn white and stop braining gets depressing and frustrating. Ports do constantly burn and we are not making it up and we are not all complete bozos (only a vast bunch of us). Those RS-485 chips (marked TI VP1782) are actually notorious for being super sensitive to ESD. At least PLEASE put those chips on a socket (surface soldering is not for the average bozo) so we can just get a bag of them (while supplies last, soon we’ll have to get them at 15x the price from scalpers like graphics cards or PS5) and replace them when they burn, just like good old fuses. Also, RS-485 chips more resilient to ESD seem to exist, at least as far as their datasheet goes (link). The TI datasheet specifically mentions the need for TVS diodes. Could be wrong / blind / bozo but can’t see them on these images, there are resistors and condensers, no diodes (link). Apparently without the diodes, the chip should handle 16Kv of ESD. According to Google a human body can produce max 15Kv (bozos walking in socks on carpet dragging their feet). So then how do these burn on antistatic tiles by just driving the robot around and not actually touching it? The more you learn, the more you don’t know. Again, ports on brains burning - whether we are bozos or not - a real thing, we are not making it up.