No Wifi on MiniPCB v2 #wemos


Howard Dutton
 

On Tue, Apr 27, 2021 at 09:08 AM, Sam wrote:
By passed or not, I still needed to press down on the Wemos.
Yea they can be tricky that way.


YviundAlex@...
 

on the other hand the ESP8266 has a spec of 2.5-3.3V, so I agree that the buck converter is not the problem :)  lucky that it helped to solve the problem :) :) :)


Chip Louie
 

On Tue, Apr 27, 2021 at 09:08 AM, Sam wrote:
On Tue, Apr 27, 2021 at 08:55 AM, <YviundAlex@...> wrote:
The buck converter in the WEMOS needs 4.3V to bring the neccessary 3.3V for the main chip....the natural voltage drop at the diode could bring up the problem....It could be that the small resistance between the pins and the socket makes the difference....can you resolder all (espcially the power pins) of the WEMOS? 

THANK YOU VERY MUCH ALEX for helping me go through the process of troubleshooting. Nearly 24 hrs... of continued trouble shooting. The problem could be a bad socket. When I press down the Wemos on the PCB IT WORKS.

I'll follow your instruction to desolder and resolder the headers. The diode wasn't the problem at all. By passed or not, I still needed to press down on the Wemos.

A fellow on r/ESP8266 mentioned that 4.3v was enough voltage to power the entire thing so that wasn't the issue.

The solder joints on the Wemos header strips look cold, like they did not really flow well to the pads on the circuit board. When reflowing the solder joints be sure to use some flux and be sure to touch the soldering iron too to the pads on the circuit board so you get that flow as seen on the pads on the power connector. 

Good luck!
 
--

Chip Louie, Chief Daydreamer Imagination Hardware


Howard Dutton
 

On Tue, Apr 27, 2021 at 09:25 AM, <YviundAlex@...> wrote:
Howard, according to my dtasheet these are ME6211 and tey are quoted with 4.3V neccessary
https://datasheet.lcsc.com/szlcsc/Nanjing-Micro-One-Elec-ME6211C33M5G-N_C82942.pdf
They're 100mV dropout and the specs seem fine to me, we don't need all 500mA.


YviundAlex@...
 

On Tue, Apr 27, 2021 at 09:34 AM, Howard Dutton wrote:
On Tue, Apr 27, 2021 at 09:25 AM, <YviundAlex@...> wrote:
Howard, according to my dtasheet these are ME6211 and tey are quoted with 4.3V neccessary
https://datasheet.lcsc.com/szlcsc/Nanjing-Micro-One-Elec-ME6211C33M5G-N_C82942.pdf
They're 100mV dropout and the specs seem fine to me, we don't need all 500mA.

Agree!!


Sam
 

On Tue, Apr 27, 2021 at 09:32 AM, Chip Louie wrote:
On Tue, Apr 27, 2021 at 09:08 AM, Sam wrote:
On Tue, Apr 27, 2021 at 08:55 AM, <YviundAlex@...> wrote:
The buck converter in the WEMOS needs 4.3V to bring the neccessary 3.3V for the main chip....the natural voltage drop at the diode could bring up the problem....It could be that the small resistance between the pins and the socket makes the difference....can you resolder all (espcially the power pins) of the WEMOS? 

THANK YOU VERY MUCH ALEX for helping me go through the process of troubleshooting. Nearly 24 hrs... of continued trouble shooting. The problem could be a bad socket. When I press down the Wemos on the PCB IT WORKS.

I'll follow your instruction to desolder and resolder the headers. The diode wasn't the problem at all. By passed or not, I still needed to press down on the Wemos.

A fellow on r/ESP8266 mentioned that 4.3v was enough voltage to power the entire thing so that wasn't the issue.

The solder joints on the Wemos header strips look cold, like they did not really flow well to the pads on the circuit board. When reflowing the solder joints be sure to use some flux and be sure to touch the soldering iron too to the pads on the circuit board so you get that flow as seen on the pads on the power connector. 

Good luck!
 
--

Chip Louie, Chief Daydreamer Imagination Hardware
They look cold solder joints by virtue of bad lighting and poor flux cleanup with IPA. But they are proper joints.

The problem looks like the female sockets are not level with the board causing the D5 and lower pins of the Wemos not contacting the female sockets properly.


Dave Schwartz
 

I also see that you've used the wrong type of female header for the WeMos. The ones you used are the 'machined' type intended to be used with the type of leg you see on discrete IC's, not the chunky square pins being used universally on module pins. Those machined sockets, while the opening is big enough, have a little spring strip in bottom intended to grip the thin IC legs. If you push a chunky pin into them, it will destroy the spring tension by over-bending it and it will never again make reliable contact for future insertions.

Been there, done that.

You should be using the type of header you have used for the driver headers. They have a little single-piece tuning-fork shaped contact intended to grip opposite sides of the pin due simply to the natural spring of the contact shape. They have the correct dimension to the gap so that they are not deflected too far during insertion so they are good for multiple insertions. Its not a large number (I'd have to look it up in the datasheet) but it is more than one (when not abused).


Dave Schwartz
 

I see you also used those machined type headers for the Teensy. I predict you'll have problems there too.

On 2021-04-27 1:39 p.m., Dave Schwartz wrote:
I also see that you've used the wrong type of female header for the WeMos. The ones you used are the 'machined' type intended to be used with the type of leg you see on discrete IC's, not the chunky square pins being used universally on module pins. Those machined sockets, while the opening is big enough, have a little spring strip in bottom intended to grip the thin IC legs. If you push a chunky pin into them, it will destroy the spring tension by over-bending it and it will never again make reliable contact for future insertions.

Been there, done that.

You should be using the type of header you have used for the driver headers. They have a little single-piece tuning-fork shaped contact intended to grip opposite sides of the pin due simply to the natural spring of the contact shape. They have the correct dimension to the gap so that they are not deflected too far during insertion so they are good for multiple insertions. Its not a large number (I'd have to look it up in the datasheet) but it is more than one (when not abused).


Howard Dutton
 
Edited

On Tue, Apr 27, 2021 at 10:39 AM, Dave Schwartz wrote:
I also see that you've used the wrong type of female header for the WeMos. The ones you used are the 'machined' type intended to be used with the type of leg you see on discrete IC's, not the chunky square pins being used universally on module pins. Those machined sockets, while the opening is big enough, have a little spring strip in bottom intended to grip the thin IC legs. If you push a chunky pin into them, it will destroy the spring tension by over-bending it and it will never again make reliable contact for future insertions.
The headers should be machined (matching pin and socket) as the case height is small.

I assume this is one of George's kits and should be the correct parts.


Dave Schwartz
 

That's not a very robust implementation. It might work for a few insertions but will fail after relatively few cycles.

If there is enough headroom for the stepstick modules with the 'tuning fork' type headers, why would you need to lower the WeMos or Teensy (its their pins that are going to largely determine the height above the PCB anyway)? They don't appear to have any components that stick up higher above the module PCB more than a millimeter or two - its not like they have jumper pins like the Blue/Black pill do. No higher than the RJ sockets anyhow.

On 2021-04-27 1:44 p.m., Howard Dutton wrote:
On Tue, Apr 27, 2021 at 10:39 AM, Dave Schwartz wrote:

I also see that you've used the wrong type of female header for
the WeMos. The ones you used are the 'machined' type intended to
be used with the type of leg you see on discrete IC's, not the
chunky square pins being used universally on module pins. Those
machined sockets, while the opening is big enough, have a little
spring strip in bottom intended to grip the thin IC legs. If you
push a chunky pin into them, it will destroy the spring tension by
over-bending it and it will never again make reliable contact for
future insertions.

The headers should be machined (matching pin and matching socket) as the case height is small.

I assume this is one of George's kits and should be the correct parts.


Sam
 

On Tue, Apr 27, 2021 at 10:58 AM, Dave Schwartz wrote:
That's not a very robust implementation. It might work for a few
insertions but will fail after relatively few cycles.

If there is enough headroom for the stepstick modules with the 'tuning
fork' type headers, why would you need to lower the WeMos or Teensy (its
their pins that are going to largely determine the height above the PCB
anyway)? They don't appear to have any components that stick up higher
above the module PCB more than a millimeter or two - its not like they
have jumper pins like the Blue/Black pill do. No higher than the RJ
sockets anyhow.

On 2021-04-27 1:44 p.m., Howard Dutton wrote:
On Tue, Apr 27, 2021 at 10:39 AM, Dave Schwartz wrote:

I also see that you've used the wrong type of female header for
the WeMos. The ones you used are the 'machined' type intended to
be used with the type of leg you see on discrete IC's, not the
chunky square pins being used universally on module pins. Those
machined sockets, while the opening is big enough, have a little
spring strip in bottom intended to grip the thin IC legs. If you
push a chunky pin into them, it will destroy the spring tension by
over-bending it and it will never again make reliable contact for
future insertions.

The headers should be machined (matching pin and matching socket) as
the case height is small.

I assume this is one of George's kits and should be the correct parts.
This didn't come from Georges kit although I followed the instructions on the Wiki to use machined headers since it will be placed in the recommended aluminum enclosure.

I used machined male and female headers on the Teensy and Wemos (The teensy and wemos didn't come with soldered headers from the factory so I simply soldered in the machined male headers I have) so they are a match.

Also, I have been told that machined headers are more robust than the regular tuning fork headers commonly used and the same type I use with the stepper drivers.

I have checked the regular tuning fork headers on the Teensy and Wemos and if I used them the Teensy would be too high, as well as the Wemos, to fit on the 70x100x25 aluminum enclosure.

The reason I am having a bad connection is that I soldered the right side machined female headers of the Wemos incorrectly. The headers weren't flush with the MiniPCB which caused the pins D5 and below to not properly contact the female socket as it was lower.