💬 Livolo 3 buttons US/AU switch adapter

[Nca78]

@tonnerre33 said in 💬 Livolo 3 buttons US/AU switch adapter:
if the atmega is out off service.

Never seen that before without frying it with too high voltage, or bricking it with failed bootloader writing.
If it happens in the wall switch, the high voltage will also fry the TTP223 and you won't get any touch function to make a "or" with :P
It would also block you from doing any "advanced" use of the buttons, like long touch, double touch, ...

[Samuel235]

Personally, i don't think there is a need to have with working without the ATMega. If it was mine, i would like to have a pretty sure way of seeing there is a problem, not to be able to continue using the product even if it was 'broken' to an extent. I see why you would like that feature but i just don't see it being much use. If you have a specific case that you would like to put forward or i'm not seeing any serious use of this, please advise me as i would change my mind :)

Just my opinion about this case would be that if i knew it was broken but could still use it without an issue then i would be rather lazy and not change the atmega straight away. But that may just be me alone, everyone else may not be as busy/lazy as me. Maybe that is the engineer inside of me coming out though haha.

[Nca78]

It would take 2 minutes to put back the original Livolo touch plate anyway, so IMHO not worth adding other components = more complexity = higher risk of failure.

[tonnerre33]

@Nca78 @Samuel235
Thanks you for your arguments, both of you.
You're right, if the atmega was broken, the best way is to stop use this node because some components could be broken too.
This feature can permit to use the command when a problem with the radio or the controler appear.
But with MY_TRANSPORT_WAIT_READY_MS , maybe we don't need this feature anymore ?
You convainced me to undo this feature and minimise the components mostly if Livolo will make many updates.

[tonnerre33]

Hi all,

As you requested, if someone want to check the board, i have adapted it for LINOVO 2 gangs 1 way EU format.

You can find the files her https://github.com/tonnerre33/Linovo_EU_2Gang_1way/tree/develop/ ;)

[MiKa]

@tonnerre33
Perfect, Thank You!
:thumbsup:

[mtiutiu]

@tonnerre33

Hi,

Nice work. I was very curious regarding on how did you made the pcb layout so I took a little time to inspect it and I noticed that you added a ceramic resonator but it's placed a little bit too far from the MCU pins. Now I know why you did that and this is the reason I didn't used a crystal/ceramic resonator in the first place - that's because of the limited space available. When I say limited is because of many reasons:

1. it's not ok to have traces/components under and/or too close the touch pads
2. didn't wanted to place components on the other side of the board because that's where the livolo glass panel comes and it may interfere from a mechanical point of view

That said I gave up on using a crystal/ceramic resonator and in most of the cases the internal 8MHz RC oscillator is more than enough(as far as I know it only matters when you have an environment where temperature variations are pretty significant so the MCU oscillator frequency can drift a lot).

Now getting back to your board and crystal/ceramic resonator placement: it's advisable to have it as close as possible to the MCU pins where it connects to and this is to reduce parasitic inductance/capacitance that long traces can and will create. Remember that 8MHz is pretty high frequency so even short traces matter so you don't want surprises in your circuit.

Other notes:

1. filtering caps for MCU need to be placed also as close as possible to Vdd pins(and for Aref too).
2. the big polarized capacitors(tantalum and/or electrolytic) need to have lower value ceramic capacitors around 100nF placed in parallel in order to reduce their high ESR

Oh and please stop using Eagle in the future :simple_smile: ..I was a former user of Eagle and now I'm really glad I got rid of it trust me. Aside from the limitations that it has and now even more as it was acquired by Autodesk it doesn't have some VERY useful features like KiCAD has now when it comes to pcb routing( one of them is push and shove ). Now I know it's hard to gave up on a tool that you used for a very long time(it was for me too) but with a little effort and small steps it can be done. And I know that KiCAD it's not that stable as Eagle is but it's still very usable(even with nightly builds that I use because of the new and nifty features). It has a little different learning curve and it's a little bit hard in the beginning but after you master it then it's a kids play. Not to mention that you have a 3D viewer for your board(very useful for mechanical integration and inspection) and it supports step models(in the nightly builds for sure).
I'm making all of my designs using KiCAD for a long time now and I didn't had issues with the final PCB even if I use nightly builds. And on top of all of this: it's FREE and no limitations and great community support on https://forum.kicad.info.

I know that you're still working on it so the pcb layout might change but I just wanted to give my first impressions on it. Good luck with your design and keep up the good work.

[tonnerre33]

@mtiutiu said in 💬 Livolo 3 buttons US/AU switch adapter:
Hi,

thanks you for your feedback ;)

Whatever the distance, i try to place all the time a ceramic resonator just for debug. Indeed, i have already brick my atmega with wrongs fuses and i had to add a resonator for change them again.

I did that on other project even if i use the 8Mhz internal oscillator.

For the distance, i didn't now the limit with 8Mhz.

I was thinking i have placed the caps for MCU like your project, isn't it ?
I didn't know the problem of the big tantalum capacitor (Is 100nF big ?) I'll place a 100nF ceramic capacitor in parrallel of the tantalum capacitor in a next rev.

I have tried kicad but when i have printed the PCB it was blurrier than the same maked with eagle. I was afraid with that, that's why i continu with eagle for the moment.

I'am glad that you looked this pcb, a big thx again.

Edit : on the linovo pcb, why they don't put a ceramic capacitors near the tantalum capacitor ?

[mtiutiu]

@tonnerre33

I wasn't referring to the 100nF ones which are ceramic type usually. If I remember well I saw some 10uF or 100uF in parallel in your schematic (the polarized capacitors) so I was assuming that you use tantalum ones.

[tonnerre33]

@mtiutiu said in 💬 Livolo 3 buttons US/AU switch adapter:
Oh sry, i read the wrong value, and now i'm agree 100u is big ;)

[achurak1]

So how's the testing going? I'm thinking to try to have seeed to print and assemble the pcb for me as I hate to even think about soldering all of these smd parts manually :)

[Nca78]

@achurak1 I have problems with the touch sensors, I'm redesigning the PCB now to improve sensibility.
The good news is radio performance is great, not a single failure.

[achurak1]

@Nca78 Awesome, thanks for the update!

[Nca78]

Just finished the new version of the board, I'll check it again tomorrow and send it to Seeed to get the PCB.

[achurak1]

@Nca78 - Great! Do you believe the new version has all of the issues fixed?

[Nca78]

@achurak1 said in 💬 Livolo 3 buttons US/AU switch adapter:

@Nca78 - Great! Do you believe the new version has all of the issues fixed?

Else I wouldn't say it's "finished" ;) (but be careful it's not online yet...)
Did all items in the "todo list" on openhardware.io page, I just had a problem with the holes to put the plastic circles as I had too many wires going to the radio, so it won't be possible to use those from the Livolo switch. They are not absolutely necessary but I will make a 3D printed "separator" to block the light between the different switches.

I also added more extra leds to the center button, there are 4 extra leds now in case you want to use center button for mode/scene selector.

[achurak1]

@Nca78 - makes sense :) When are you going to upload the gerber files?

[Nca78]

@achurak1 said in 💬 Livolo 3 buttons US/AU switch adapter:

@Nca78 - makes sense :) When are you going to upload the gerber files?

When I can confirm all problems are solved :P
Should not be too long I will send to Seeed tomorrow or Friday and use Fedex or DHL, their prototype PCB price is so insanely low now (4.9$ for up to 10*10cm) that from the 2nd PCB it's cheaper with them using DHL than with DirtyPCB :o

[Nca78]

I just posted new design files and gerber files (but please don't order now, I will receive PCBs only on Friday and then I need a few days before I can test them...

I also put a bit of documentation but it still needs (a lot of) improvements :)

[achurak1]

@Nca78 - Thanks for the update! Looks like shipping takes a lot of time even with the DHL delivery. Will be waiting for you to test and give us green light to order the PCBs :)