I got my hands dirty on Resin 3D printing for the very first, Results are flabbergasting. A word of

I got my hands dirty on Resin 3D printing for the very first, Results are flabbergasting.

A word of caution for those who wanna try the same:
This model took 3 hrs to print, 30mins of post processing and almost 2.5-3hrs to clean all the mess

PPadmalaya Rawal I got my hands dirty on Resin 3D printing for the very first, Results are flabbe...

nour_oud•1/19/24, 6:56 PM

Good job

shardul17•1/19/24, 7:20 PM

Hello guys,

I wanted to know more about standardised architecture of linux based embedded system.

My system is having Digital IOs, Analog IOs, CAN, Modbus over RS485, RTC, Web server etc....

Hardware is ready. Also, it's working smoothly but i dont want it to be tightly coupled.

What i want is every other module will work independently and i will code the application (Custom logic) only as per requirement.

Any suggestions, posts, links.....i am relatively new to this.
Thank you...!!

Sshardul17 Hello guys, I wanted to know more about standardised architecture of linux base...

abhishek awasthi•1/19/24, 7:50 PM

as the requirement you have provided ... i feel that all these input interrupts and outputs should have thier own logic and so some kind of ipc ... in that situation you can utilize some ipc methods or else you may use ros as an architect ... where everything is a pub sub structure and considered as nodes ...

abhishek awasthi•1/19/24, 7:51 PM

also may i know the environment and mpu details ..

abhishek awasthi•1/19/24, 7:51 PM

build environment*

abhishek awasthi•1/19/24, 7:58 PM

here by ipc i mean ... inter procedure communication ...

kristof-at-embeetle•1/19/24, 11:31 PM

kristof-at-embeetle•1/19/24, 11:31 PM

I'm placing TVS diodes at all the IO pins

kristof-at-embeetle•1/19/24, 11:32 PM

For example:

kristof-at-embeetle•1/19/24, 11:32 PM

kristof-at-embeetle•1/19/24, 11:38 PM

I also installed plenty of 'security' at the USB port:

kristof-at-embeetle•1/19/24, 11:38 PM

kristof-at-embeetle•1/19/24, 11:43 PM

(1) TVS DATA LINES
TVS Diodes protect the USB data lines against voltage transients.

(2) TVS 5V POWER
A larger TVS diode is placed on the 5V power incoming from the USB connector to deflect voltage transients.

(3) ZENER 5V + (4) FUSE
A zener diode of 5V6 (I took a bit of margin) is connected to the 5V USB power line. A permanent overvoltage will short through this zener diode and burn the fuse. The rest of the circuit should be fine.

(5) PMIC 500mA
A

AP2141WG-7

AP2141WG-7

chip lets only 500mA pass through from the incoming USB power to the rest of the board. In case of overcurrent it will shut down and lit the

ERR

ERR

LED.

fwen•1/20/24, 1:31 AM

That sounds wayyyy overkill for such a cheap microcontroller

fwen•1/20/24, 1:31 AM

Like for me personally I think replacing the microcontroller itself would be cheaper

techielew•1/20/24, 4:18 AM

@Wired & Wireless Networking folks, any suggestions on the best MQTT client software to use when testing MQTT topics during development? At least as far as ease of use and security are concerned..?

Ttechielew @Wired & Wireless Networking folks, any suggestions on the best MQTT client sof...

abhishek awasthi•1/20/24, 4:20 AM

mqtt explorer is what i prefer for the ease of usage

Aabhishek awasthi mqtt explorer is what i prefer for the ease of usage

techielew•1/20/24, 4:29 AM

Nice! Thanks. I'm looking into it. Looks like it checks a lot of boxes around open source, platform support, and decent enough documentation, BUT...

Is it still being maintained?

https://mqtt-explorer.com/

MQTT Explorer

An all-round MQTT client that provides a structured topic overview

techielew•1/20/24, 4:30 AM

Also, how and from where do I know Thomas Nordquist nerdthinking

... I can't put my finger on it...

Ttechielew Also, how and from where do I know Thomas Nordquist <:nerdthinking:8080573401539...

Umesh Lokhande•1/20/24, 4:36 AM

Even I use MQTTExplorer daily but when working with sensitive applications, especially for security where we need to upload files (.crt, private or public.pem etc). I prefer MQTTFx. For a mobile client, also recommend looking into the MyMQTT App if security is not a concern

UUmesh Lokhande Even I use *MQTTExplorer* daily but when working with sensitive applications, es...

techielew•1/20/24, 5:15 AM

Costs $$

Umesh Lokhande•1/20/24, 5:42 AM

Yes, unfortunately, *MQTTFx *costs $ starts at 49.90€. For free as Abhishek said MQTTExplorer is good to get the job done!

DevHeads•1/20/24, 9:51 AM

Congrats @Deepak ! You've been Verified!

Saßì•1/20/24, 9:55 AM

@Deepak Welcome , Can you tell us a little about yourself and your technical background? What brings you to DevHeads? What are you working on currently?

DevHeads•1/20/24, 11:35 AM

Congrats @topgun3237 ! You've been Verified!

Saßì•1/20/24, 12:06 PM

@topgun3237 Welcome! will be happy to know your technical background and what project you're working on these days.

Ffwen That sounds wayyyy overkill for such a cheap microcontroller

kristof-at-embeetle•1/20/24, 12:10 PM

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-embeetle•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-embeetle•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-embeetle•1/20/24, 2:11 PM

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

Then I put the fuse.

kristof-at-embeetle•1/20/24, 2:12 PM

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

kristof-at-embeetle•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-embeetle•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-7

AP2141WG-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

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