Hi Guys,
I think I figured out the main problem.

It has nothing todo with the SPI bus ... It´s the 3,3V line.

Take a look at the picture. If you set the LCD to 80 (~33%) brightness then the PWM signal is extremly present on the 3,3v line ... And the MCP3204 don´t like that :-)

And this is a picture with 255 (100% on) brightness ...

No further explanation needed ...

Dominik

Hi!

I just wanna show you my new invention ... the M5Stack Data Gloves :-)

The design based on the DIY arduimu gloves (which you can´t find any longer because the website is down :-( ).
Anyway. I redesigned some parts, learned sewing and now I`m close to build the sensor stuff.
I did some work on the code, too ...

Will keep you up to date if I did my first tests und if the code part is done.

So be patient :-)

Dominik

Hi @all,
to be honest I´m a little bit confused about the M5 Fire device. As stated in the documentation there is a MPU6050+MAG3110 build in the fire.

So there are some questions (at least for me) unanswered :-)

1. Why is there a MPU6050+MAG3110 combination build in the fire where the gray one has a MPU-9250 ?
2. How can you use code from the M5 gray on the fire without recoding the whole IMU stuff?
3. Why tells the github example that there is a MPU9250 in the fire :
   https://github.com/m5stack/M5Stack/blob/master/examples/Fire/M5StackFire_MPU9250/M5StackFire_MPU9250.ino

Very confusing at all. Is anyone here able to bring a little bit of light into the darkness :-) ?

Dominik

Hi,
is there any way to print rotated text to the screen?
Like here:

regards
Dominik

Hi Rob.
Yes there are 100nF directly at the Power supply of the Mcp3204.
But that won't help. I Ordered some lm4040 to have a clean voltage reference.
I think that will help.

Regards
Dominik

Hi Guys,
I think I figured out the main problem.

It has nothing todo with the SPI bus ... It´s the 3,3V line.

Take a look at the picture. If you set the LCD to 80 (~33%) brightness then the PWM signal is extremly present on the 3,3v line ... And the MCP3204 don´t like that :-)

And this is a picture with 255 (100% on) brightness ...

No further explanation needed ...

Dominik

Hi guys,

today I spent some time getting my MCP3204 working. It´s a 4 channel ADC with an SPI Bus.
I connected the MCP like this:

#define SPI1_CLK  18  // D -> Clk   -> Pin 11  
#define SPI1_MISO 19  // Q -> D Out -> Pin 10     
#define SPI1_MOSI 23  //   -> D In  -> Pin  9    
#define SPI1_SS   16 //    -> CS    -> Pin  8   

It´s working as expected as far as I don´t use any display stuff from the M5 Stack.

As soon as I ad the following to my code:

 M5.begin(); // true, false, false);
 M5.Lcd.printf("TEST");

things getting wired. The readings of my MCP3204 are wrong.

I convert the AD values to temperature vales since I use some BBQ sensors. And the results are about 2 degrees wrong when adding the M5 Display.
Example: Reading temp without Display -> ~21° and with display ~23° or sometime ~17°
I can do some addition checks with the plain AD values to get a better understanding.

But anyway ... What´s wrong in using the SPI bus for a second device?
Are there any drawbacks i don´t know? Any issues?

Maybe someone has some explanation for this topic.

Dominik

Hi ferrianf,

Some days ago I asked a similar question about powering the stack.
And until now there are no answers from the M5Stack employees. It's absolutely not understandable why those guys don't answer so important questions. And furthermore why there is no documentation about that power topic. :-(

Anyway ... Did you take a look into the IP5306 datasheet? Maybe you can find some answers there?

Sorry if I can help more.

Dominik

Hi,

@lukasmaximus 在 M5 Data Glove 中说：

what kind of sensors are you putting in it? flex sensors in the fingers?

Correct. I use 4 Flex Sensors in the Fingers. They 2,2" types from SparkFun.
I hope to get them working until sunday ...

@lukasmaximus 在 M5 Data Glove 中说：

I made a simple music glove before with flex sensors it was a lot of fun.

Did you have any photos? How did you sew the glove?
I found it really hard to get this glove as far as it is now. There are not really a lot of information in the web available ...

Dominik

Hi!

I just wanna show you my new invention ... the M5Stack Data Gloves :-)

The design based on the DIY arduimu gloves (which you can´t find any longer because the website is down :-( ).
Anyway. I redesigned some parts, learned sewing and now I`m close to build the sensor stuff.
I did some work on the code, too ...

Will keep you up to date if I did my first tests und if the code part is done.

So be patient :-)

Dominik

@ajb2k3 在 External Power - What is possible? 中说：

You are aware that there are 2 battery connection on the M5?
1 is in the 2x15 connection, one is on the actual main pcb.

Yes I saw that. I think that both directly connected to the VBat connection, correct?!

@loboris 在 External Power - What is possible? 中说：

5V connection on the 2x15 connector is the output from IP5306 VOUT pin

Well if there is no battery connected and no USB cable attached ... Why should this be a problem?
I would assume that the IP5306 has an internal protection for reverse current.

Hi,
cutting traces on the PCB is always a bad idea I think ...

But connecting a 5V source to the 5V connection on the 2x15 connector should be ok, or not? If there is no battery connected we don need the IP5306?

you should not connect USB cable at the same time the external 5V is connected

That's correct but this is a compromise I can live with.

regards Dominik