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nilclass, in Communication protocol suggestion for peer-to-peer device network?

You could give PJON a try github.com/gioblu/PJON

surepancakes,

This seems more than interesting. Will check it out in detail, since I haven’t heard about it until now. Thanks for the suggestion!

irdc, in Struggling to find a PCIe USB controller IC. Either unavailable or expensive

How many do you need? If it’s for a prototype, scavenging them from retail hardware isn’t necessarily a bad idea.

oldfart, in Communication protocol suggestion for peer-to-peer device network?

CAN BUS is relatively easy to implement and ticks your boxes

surepancakes,

Thank you for your suggestion. Is it really that easy to implement? So far the people I talked with irl told me otherwise, but I will look into it and judge myself whether I am up to the task.

oldfart,

Exactly, hard/easy depends on your background. It’s been almost 20 years since I worked with it, I’m sure there are ready made libraries or chips implementing 99% of the protocol these days.

h3ndrik, in Communication protocol suggestion for peer-to-peer device network?

maybe RS-485 or CAN

surepancakes,

Thank you for your suggestions. Rs-485 seems to be what I was looking for. CAN could also work, but is it reasonably implementable? So far everyone who I spoke with about CAN said that it is a rather complex protocol with a lots of finicky details and an extra long standard. Perhaps I have just talked to the wrong people. I will look into it more thoroughly, and thanks again.

h3ndrik,

I might be a bit spoiled by the ESP32 and all its supported protocols.

beeng, in Communication protocol suggestion for peer-to-peer device network?

MQTT?

azdle,
@azdle@news.idlestate.org avatar

MQTT isn’t peer-to-peer, it requires a centralized broker that all devices connect to.

If OP were looking at network protocols, CoAP would be the right option, but it looks like they don’t even want to bother with IP.

surepancakes,

Indeed, I was looking for a simpler and lower level protocol. Thanks for mentioning the network protocol anyway, because I have never heard of CoAP until now. It may come in handy in the future (or maybe for someone else reading the post).

wildbus8979, in Communication protocol suggestion for peer-to-peer device network?

Sounds like you want ethernet.

surepancakes,

Hmmm… It does tick a lot of the boxes, but the ethernet protocol is way too complex with all of its layers and not reasonably implementable on a low-power microcontroller. Also it requires separate hubs for connecting multiple devices together unlike i2c, which is daisy chainable.

wildbus8979,

A lot of microcontrollers, ESP32 or STM32F4 to give two examples, have the PHY built in.

But if that’s too much for your taste, then CAN bus might be what you’re looking for.

skillissuer, in Neat trick for desoldering many-pin components
@skillissuer@discuss.tchncs.de avatar

this only works well if you have good soldermask in place

Sir_Kevin, in Neat trick for desoldering many-pin components
@Sir_Kevin@discuss.online avatar

I was ready to shit on this but I could definetely see some uses when there are a lot of through hole pins. I’d be a little worried about keeping the heat distribution even though.

naonintendois,

I thought it might be useful to move the iron back and forth a little for long rows. Wouldn’t be perfectly even but would be better than concentrating heat in the center.

Rolive,

Well the copper should disperse the heat fairly quickly. It should be okay.

lxpw, in Neat trick for desoldering many-pin components

I picked up a Hakko desoldering gun many years ago to save me from this. It was pricey (~$300), but has been worth it over the years.

naonintendois,

This trick might be more useful for people who are budget constrained. In the past I’ve resorted to cutting the plastic between the headers (making them unusable), so this is a nice alternative without the need for another tool. If budget wasn’t an issue I’d likely buy a much nicer iron and an extra wide knife-style tip.

Saigonauticon,

Haha, I’ve done that too. However sometimes it rips the pads off or otherwise damages the vias. So instead I cut them along the other axis (parallel to the PCB), then remove the remaining nibs.

These days I mostly use a hot air rework station though. In my city this is integrated with many soldering stations on the market, for maybe an extra 10$. I think mine is Yihua brand, it’s quite OK.

deksesuma,

Same. It’s been a lifesaver and a confidence booster because I know I can more easily recover from mistakes.

dmention7, in What is this "220?" component and how do I determine a compatible replacement?

Maybe I’m looking at the wrong thing, but I don’t see melted plastic. I see a collapsed bubble (a “fisheye”) in the conformal coating that is providing moisture resistance to the components.

RedBauble, in What is this "220?" component and how do I determine a compatible replacement?

They are 22ohm resistors. You can see they are resistor by the marking R on the pcb. The first two digit is the value (22), the last is the multiplier (0), so it would be 22*10^0 =22 ohm

H3wastooshort, in What is this "220?" component and how do I determine a compatible replacement?

I dont think the resistors are faulty but the design. Resistors (especially low-ish value 22Ohm ones) are meant to dissipate energy as heat. Putting them in a cramped housing made of plastic, then using them to dissipate high power is going to build up heat in there. There could also be another component faulty that puts too much current into the resistors. They are probably part of the balancing circuit.

mvirts, in What is this "220?" component and how do I determine a compatible replacement?

Clearly R27 is installed backwards 😹 oh yeah also you can guess that they’re resistors because the label (screen print) uses an R to identify them

chinpokomon,

As a resistor, there isn’t a forward or backwards. Diodes and some capacitors perhaps, but resistors have no forward or reverse bias. Upside down might be a problem because all the electrons will fall out. /s

mvirts, in What is this "220?" component and how do I determine a compatible replacement?

You can replace it with any resistor with the same resistance and power rating. It may be easier to solder a larger through hole resistor onto the pads. I think other posters have figured it out, but you can search for resistor code information to decode it yourself. You can buy resistors lots of places, RadioShack was the go to place but I think hardware stores sometimes have them. If you’re not in a rush I recommend ordering a kit with a few different kinds.

Lemmesee, in What is this "220?" component and how do I determine a compatible replacement?

Looks like a 22 ohm resistor

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