Display custom text on MAX7219

ESPHome
1

Hi there,

I want to display custom text on my MAX7219 via ESPHome. So I created a input_text helper, which I want to update and the updates text should then be displayed on the matrix.

This is my ESPHome device config:

spi:
  clk_pin: D5
  mosi_pin: D7

display:
  - platform: max7219digit
    cs_pin: D4
    num_chips: 4
    intensity: 15
    lambda: |-
      it.printf(0, 0, id(digit_font), "%s", id(matrix_text).state);
      
font:
  - file: "common/pixelmix.ttf"
    id: digit_font
    size: 9

time:
  - platform: homeassistant
    id: hass_time
    
text_sensor:
  - platform: homeassistant
    name: "Matrix Text"
    id: matrix_text
    entity_id: input_text.matrix_text

Can this work? I get this error on compile:

src/main.cpp: In lambda function:
src/main.cpp:262:59: error: cannot pass objects of non-trivially-copyable type 'std::string {aka class std::basic_string<char>}' through '...'
       it.printf(0, 0, digit_font, "%s", matrix_text->state);
                                                           ^
src/main.cpp:262:59: warning: format '%s' expects argument of type 'char*', but argument 6 has type 'std::string {aka std::basic_string<char>}' [-Wformat=]

Can somebody tell my what I need to change in order to get this working?

Thanks!

2

Hi Zoker!
Seems here the answer - https://esphome.io/components/text_sensor/mqtt_subscribe.html

it.printf(0, 0, id(font), "The data is: %s", id(mysensor).state.c_str());
1 Like
3

Yes thanks, now it compiles and does not throw any issue anymore. But the matrix just stays empty. Do you have any idea why?

The entity does have this value:

image
image880×374 19.3 KB

4

Looks like alignment issue?!. Try to play with font size and TextAlign::BOTTOM_LEFT
I will try the same on my test matrix panel.

UPDATE:
Checked. Works correctly in my case. I’m using codi.ttf font - https://www.dafont.com/codi.font

5

Your yaml does not include the API.
Did you forget that or is it excluded from your copy paste here?

6

I actually forgot to add the ESPHome device to HA (I didnt notice before, because the time component seemed to work without adding it).

Yes I forgot to copy it, but it was/is there :slight_smile:

7

:smile: I caught it myself.
Another good check is:

if (id(matrix_text).has_state()) {
   it.printf(0, 0, id(digit_font), "%s", id(matrix_text).state.c_str());
} else {
   it.printf(24, 0, id(digit_font), "Nothing to show");
}
8

Can you give some instructions for this? The letters are on the half top left.

IMG_20200922_191405
IMG_20200922_1914054624×2136 196 KB
Here its written AAAAAA. I have tried everything BOTTOM, CENTER, BASELINE, BOTTOM_RIGHT, but when i put any of this the letters disappear. Any thoughts?
Thanks

9

This is a bug in the current version. A fix for it is already on the way:

In the mean time you can solve this by including the TextAlign parameter:

it.printf(0, 0, id(digit_font), TextAlign::TOP_LEFT, "%s", id(matrix_text).state.c_str());

Hope this help :slight_smile:

2 Likes
10

Thanks, i will try it.
Works great. Thanks

11

Cool! How I missed that! This really help with my issue - MAX7219 text alignment confused me
But I still confused which alignment does font has by default. :roll_eyes:

12

That’s why I love forums. Everyone helps everyone :smiley:
I think all it should use TOP_LEFT, but maybe there are some more bugs here.

@machine2669 BTW: The text disappears on different text alignment, because the position must be adjusted as well. So if you for example set TOP_RIGHT, the text will be gone, since it starts on pixel 0 and from there the text grows to the left (so into a area, where is not pixels). I hope this is in any way understandable :sweat_smile: