Slim Node 5V-Mod

[Soloam]

Hello all, I've been using m26872 slim node to some of my nodes, but my main problem was not being able to power it with 5V because the RF is only 3.3v. So I made some modifications to the design and now I'm asking for your help to see it and validate it! I'm no expert in electronics (not at all) and this is my first attempt with KiCat.

The main idea is to power the Radio with a LE33A step down regulator! Here is the result:

1_1460679153850_print.pdf

BOM
C1,C2,C3 : 0.1uF capacitor P-5mm (low to fit inside IC1 socket)
C5 : 0.1uF capacitor P-2.5mm
IC1 : Atmega328p
R1 : 10k resistor 1/4W
P4 : nRF24L01+
U1: LE33A

What do you think, will it work? My main concern is the Capacitors!

Thank you all.
Best Regards

PS: Credits and tanks to @m26872 for the base design and help

[GertSanders]

@Soloam

Show us also the schematic, that will be easier to check.

[m26872]

It's a good idea and the principle will work. I've not checked very detailed though. I haven't used my KiCad in a while - why do the signal traces look so thin?
If you want help with a design review it'll be better the more you share. But of course in any case you wont be sure until it's tested.
May I suggest a changed topic title to "Slim Node 5V-Mod" ? There are many other mods possible. I'm tempted to do a few myself.

[ahmedadelhosni]

@Soloam said:

w I'm asking for your help to see it an

Great design and idea.

I was replying that everything is okay until I decided to have another look. Did you switch the regulator Input and the Output ? from this reference :

The L in your layout shall be PIN3 which is Vin according to the above picture, and vice versa.

Can you please post your schemtatic. Maybe I am confused.

[ahmedadelhosni]

I was also going to refer to the thin pcb traces in the design. I haven't used KiCad yet so I don't know the default, but 10 mils is enough in our designs for a normal signal, and maybe 16 mils for Vcc and Gnd ( which is also a lot in my opinion as we don't draw a lot of current in our designs)

[scalz]

I agree too for traces. and for instance some fabhouse has a 6mil trace min but often says 8mil is recommended. So if you don't want to have broken trace during pcb fab process, it's better 8mil min or 10mil is nice, for signals For below, it's premium pcb, more expensive better quality..
I have already used 8mil because it was compact, worked ok, but 12 or 10mil is usually my setting. and for power..16 to 20mils, it depends where..lol

[Soloam]

Hi all, thank you for the replays, this is the first time that I use KiCat, so I used @m26872 design as a start up! For what I can see, the VCC and GND traces are 1,000mm and the signal traces 0,250 mm! Is it good? Not lots room in the PCB! I'll post better images, the ones that I've included are very low resolution!

@ahmedadelhosni I think you are right, I've seen an image online and this was the layout, but now I've been looking at the datasheet (noob mistake) and I think that I missed them out! Tomorrow I'll assemble the test circuit and test it out!

Thank you all

[Soloam]

Main post updated, I'll validate the LE33 pin layout tomorow and post back!

[m26872]

If you read through the connect radio - build site old comments you'll see that I've validated the labeled LE33 image posted there. If it turns out to be wrong again, please notify.

[GertSanders]

Looking at the schematic, this should work fine.

[AWI]

@Soloam Any specific reason to use LE33A? The quiescent current of this LDO is typ. between 0.5 (no load) and 1.5 mA . Unless you are using a > 6 V input voltage I would suggest using the 662K. Can be soldered by (a stable) hand, small footprint, very cheap and quiescent current of only 1 uA (typ.).

[m26872]

@AWI - the notorious SMD-free concept violator -

[AWI]

@m26872 ouch.. ok, a to-92 alternative MPC1700

But why drill holes...

[Soloam]

@SMD is a lot harder to solder, I prefere this one

I checked the LE33 and my layout is correct, that is the correct way to put it!

[Soloam]

Hi all! I have merged 3 boards into one 50x50 layout, this way I can send it to print in dirtypcbs.com and order 10 pcb's, that will make 30 nodes! The solution is similar to the one used by @m26872

[Soloam]

Order submitted, now I just need to wait for the arrival!

I started also a new project that will control my light switches.

https://www.openhardware.io/view/83

[badmannen]

@Soloam
Hello looks like a great board. Any progress on the Switch board?

//Henrik