Hi @fwen , I understand your point. However, all that protection is not so much to safeguard your "i

Hi @fwen ,
I understand your point. However, all that protection is not so much to safeguard your "investment" in the 10-cent MCU. It's intended to safeguard your time investment. See, a Transient Voltage event (eg. ESD discharge) can damage the chip slightly, such that some of its IO pins no longer work. You might not immediately figure out why your project is failing and be troubleshooting for a whole day.

Kkristof-at-embeetle Hi @fwen , I understand your point. However, all that protection is not so much ...

fwen•1/20/24, 12:35 PM

oh i thought when it's damage it just no longer work. i havent had any failed on me before. thanks for the clarification!

Kkristof-at-embeetle Click to see attachment

gKarthikSai•1/20/24, 12:37 PM

Aesthetics

pallavaggarwal•1/20/24, 12:41 PM

@kmulier ESD diodes on IOs on a dev board is not really required.

kristof-at-embeetleOP•1/20/24, 12:42 PM

Glad you guys like the aesthetics.

Why are ESD diodes not required on IO from a dev board?

pallavaggarwal•1/20/24, 12:44 PM

why do we need ESD diodes?

pallavaggarwal•1/20/24, 12:44 PM

to protect from static charge

YAGPDB.xyz•1/20/24, 12:44 PM

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pallavaggarwal•1/20/24, 12:45 PM

dev board is expected to be used in lab, which is a controlled ESD safe env most of the time

pallavaggarwal•1/20/24, 12:45 PM

so ESD diode is not really required but not harmful

pallavaggarwal•1/20/24, 12:45 PM

if you are anticipating risk of damage then we have more risk on all switches, where a person will be touching frequently

pallavaggarwal•1/20/24, 12:47 PM

one more thing I sucpect your switch and a few passives are very near to the mouting holes, please check if someone try to use screw with head, it will not touch or come very near

pallavaggarwal•1/20/24, 12:48 PM

did you use fuse after 5V TVS?

pallavaggarwal•1/20/24, 12:48 PM

it should be USB 5V>Fuse>TVS

pallavaggarwal•1/20/24, 12:48 PM

plz check

kristof-at-embeetleOP•1/20/24, 2:10 PM

@pallavaggarwal :

The screw holes are 6mm in diameter, with a 3mm diameter hole. The head of an M3 bolt is usually not more than 5.5mm. So this should be fine.
The switches themselves are in plastic. So, I suppose an ESD discharge wouldn't happen there? Or should I put a TVS diode on the switch contacts?
This is where I put the Fuse:

kristof-at-embeetleOP•1/20/24, 2:11 PM

kristof-at-embeetleOP•1/20/24, 2:11 PM

As you can see, I deliberately put the TVS Diode right at the USB connector. So a voltage transient doesn't even get the chance to enter the board.

kristof-at-embeetleOP•1/20/24, 2:11 PM

Then I put the fuse.

kristof-at-embeetleOP•1/20/24, 2:12 PM

Then I put a zener diode that will burn the fuse by shorting a permanent overvoltage.

kristof-at-embeetleOP•1/20/24, 2:14 PM

A typical case would be a faulty charger that outputs 20V instead of 5V on the USB VBUS line. Normally, a charger should only output more than 5V after a protocol has been processed with the downstream device. But in case that fails, you can potentially have 20V on the VBUS.

The zener diode will short that to GND, thereby drawing a huge current. The zener (and the traces on the board) can't sustain that kind of current for long. That's where the fuse comes in the equation.

kristof-at-embeetleOP•1/20/24, 2:17 PM

I chose a 2A fuse instead of a 500mA one, because the 2A fuses have a lower resistance in normal operation. I already cause somewhat of a voltage drop with the AP2141WG-7AP2141WG-7 protection chip. I didn't want to create yet another voltage drop with the fuse.

pallavaggarwal•1/20/24, 2:27 PM

why do you get static charge on a comb? rem school experiment?

pallavaggarwal•1/20/24, 2:30 PM

fuse might be good but even TVS, zener is over design. 5.1K on CC1/2 will make sure 5V only is coming from USB

kristof-at-embeetleOP•1/20/24, 2:41 PM

Right, I'll put a TVS on the switches. Good point
5.1K5.1K on CC1/2CC1/2 should indeed make sure no more than 5V is coming from the USB. However, I've read that some faulty chargers can at times still output 20V when defect. I just wanted to account for that - even though it's highly unlikely. I'm somewhat paranoid when designing a PCB

pallavaggarwal•1/20/24, 2:53 PM

in my point of view nothing is really required for 2/3 both

pallavaggarwal•1/20/24, 2:53 PM

rest is your call

pallavaggarwal•1/20/24, 2:54 PM

Faulty charger, earthquake

are not required to be considered for a dev board

kristof-at-embeetleOP•1/20/24, 3:35 PM

Maybe I should put a lead box around it to protect it from cosmic radiation

kristof-at-embeetleOP•1/20/24, 3:35 PM

Want to keep my 10 cent MCU alive at all costs.

kristof-at-embeetleOP•1/20/24, 3:36 PM

kristof-at-embeetleOP•1/20/24, 5:02 PM

The indestructible Tiny Scarab will be known as the Nokia of dev boards. You can use it as a hammer or a screwdriver.

Navadeep•1/20/24, 5:03 PM

Suggesting to make it RadHard and flamethrower proof as well.

kristof-at-embeetleOP•1/20/24, 5:03 PM

Cool. Will do.

Navadeep•1/20/24, 5:03 PM

@Padmalaya Rawal can have a case IP infinity case built for it

kristof-at-embeetleOP•1/20/24, 5:04 PM

Ttechielew Nice! Thanks. I'm looking into it. Looks like it checks a lot of boxes around op...

BenCos18•1/20/24, 5:31 PM

I use that a lot with my mqtt based sensors
never had an issue with it

BenCos18•1/20/24, 5:32 PM

BBenCos18 I use that a lot with my mqtt based sensors never had an issue with it

techielew•1/20/24, 6:34 PM

dyk if it's still maintained?

techielew•1/20/24, 6:34 PM

i seriously can't put where i know that guy thomas from

NNavadeep @Padmalaya Rawal can have a case IP infinity case built for it 😉

Padmalaya Rawal•1/20/24, 7:10 PM

sure

Ttechielew dyk if it's still maintained?

BenCos18•1/20/24, 7:26 PM

doesn't look like it's updated anymore sadly

BenCos18•1/20/24, 7:27 PM

https://github.com/thomasnordquist/MQTT-Explorer

GitHub

GitHub - thomasnordquist/MQTT-Explorer: An all-round MQTT client th...

An all-round MQTT client that provides a structured topic overview - GitHub - thomasnordquist/MQTT-Explorer: An all-round MQTT client that provides a structured topic overview

PPadmalaya Rawal sure😂

techielew•1/20/24, 7:31 PM

Real talk though have you created IP-rated casings electroboffin?

Umesh Lokhande•1/21/24, 6:25 AM

Any suggestion of a Mobile app to acquire the IP address of connected IoT devices to mobile hotspots? Due to security settings, some phones don't allow us to see the IP address. The goal is to quickly get an IP address and remotely access the device via SSH.

pallavaggarwal•1/21/24, 7:23 AM

angryIP to scan connected devices

Ppallavaggarwal angryIP to scan connected devices

Umesh Lokhande•1/21/24, 7:27 AM

Thank you, @pallavaggarwal unfortunately, I can't find the AngryIP scanner Android app in the Play Store. I use AngryIP on my desktop!

pallavaggarwal•1/21/24, 7:31 AM

did you try android ip scanner?

pallavaggarwal•1/21/24, 7:32 AM

you can also check apps like _Auto IP scanner, Advance IP scanner

pallavaggarwal•1/21/24, 7:32 AM

Fing is also one more app

Ppallavaggarwal you can also check apps like _Auto IP scanner, Advance IP scanner

Umesh Lokhande•1/21/24, 7:37 AM

I tried AdvanceIP, it works on some phones (android version). Will try Auto and Android IP scanners!

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