Unable to display the ° degree symbol on SH1106 and SH1107

[bruno1950]

Hi,
I'm an old(74) newbie of micropython and I'm trying to use an OLED SH1106 / SH1107 to display data from a BME280 sensor connected to an ESP32 working with uPY. While on the serial monitor the ° degree symbol is correctly printed I was not able to get it displayed on the SH1106. I tried both display.text("{:0.0f}°C".format(temperature), 0, 30) and display.text("{:0.0f}{}".format(temperature, chr(176)), 0, 30) but I keep on getting ValueError: unknown format code 'f' for object of type 'str'. I also tried to modify the line 335 of BME280.py by inserting the ° but it works only when printed in the shell while in the display there is a little white rectangle instead of the symbol.
Could you help me to fix this issue and apologies for the maybe silly question but I was not able to find a solution even after extensive googling. Thanks

[cwalther]

There are two issues here:

• The ValueError seems to indicate that your temperature variable holds a string, not a number as your format expects. Check where you got it from and whether you’re inadvertently converting it. If you originally got it as a string, you can convert it to a number using float(temperature).
• The built-in font used by framebuffer.text() only includes glyhps for ASCII characters, which does not include °. You will have to use a more sophisticated text rendering library, such as the Writer class of nano-gui. (If you consider its extra functionality like word-wrapping and scrolling overkill, it’s possible to write a simpler renderer using the same font format in just a few lines.)

[bruno1950]

Hi Thanks for your prompt answer and help. Now I'm going to check carefully my code and the links you suggested trying to find if I solve this issue. Have a nice day -- Inviato da Libero Mail

[ricksorensen]

I only have 128x64 SSD1306 OLED display and the driver for micropython also uses framebuf. Here is a snippet that works for me and does not use much extra memory.
The spacing assumes text is a 8x8 pixel cell, and I computed the spacing based on that. One could half-space too.

from machine import I2C
from ssd1306 import SSD1306_I2C
import framebuf
# simple 8x8 degree symbol, 1 pixel thick line, in the upper half of character cell
p0 = bytearray([0x18, 0x24, 0x24, 0x18, 0x00, 0x00, 0x00, 0x00])
# p1 drops symbol in cell by 1 pixel
p1 = bytearray([0x00, 0x18, 0x24, 0x24, 0x18, 0x00, 0x00, 0x00])  
# convert to framebuf- 
#    8,8 is size of blit- 8x8 pixels, 8 per row
#    MONO_HLSB indicated bit 7 is left most and bits are in rows
fb0 = framebuf.FrameBuffer(p0, 8, 8, framebuf.MONO_HLSB)
fb1 = framebuf.FrameBuffer(p1, 8, 8, framebuf.MONO_HLSB)
# i am using RP2040, use default I2C
i2c = I2C(1, freq=400000)
# create display object
ol = SSD1306_I2C(128, 64, i2c, addr=60)

ol.fill(0)
ol.show()    # erase
# row of symbols
ol.blit(fb0, 10, 10)
ol.blit(fb1, 20, 10)
ol.blit(fb0, 30, 10)
# number followed by symbol
ol.text("32.1", 20, 20)
ol.blit(fbuf0, 52, 20)
# another row of symbols
ol.blit(fb0, 10, 30)
ol.blit(fb1, 20, 30)
ol.blit(fb0, 30, 30)
# number followed by symbol followed by unit
ol.text("273", 20, 40)
ol.blit(fb0, 44, 40)
ol.text("K", 52, 40)
ol.show()

[mendenm]

If you want to rebuild micropython, you could just make your own fork that hacks the display module font, and replaces some other un-needed character code with a degree-sign glyph. It's not too hard to do a custom build, even if you are just getting into it.

[bruno1950]

Hi, thanks for your suggestion. I was able to adapt your code to my SH1107 and also to use a different from the default. Have a nice day

…

Il 22/04/2024 00:03 CEST Rick Sorensen ***@***.***> ha scritto: I only have 128x64 SSD1306 OLED display and the driver for micropython also uses framebuf. Here is a snippet that works for me and does not use much extra memory. The spacing assumes text is a 8x8 pixel cell, and I computed the spacing based on that. One could half-space too. from machine import I2C from ssd1306 import SSD1306_I2C import framebuf # simple 8x8 degree symbol, 1 pixel thick line, in the upper half of character cell p0 = bytearray([0x18, 0x24, 0x24, 0x18, 0x00, 0x00, 0x00, 0x00]) # p1 drops symbol in cell by 1 pixel p1 = bytearray([0x00, 0x18, 0x24, 0x24, 0x18, 0x00, 0x00, 0x00]) # convert to framebuf- # 8,8 is size of blit- 8x8 pixels, 8 per row # MONO_HLSB indicated bit 7 is left most and bits are in rows fb0 = framebuf.FrameBuffer(p0, 8, 8, framebuf.MONO_HLSB) fb1 = framebuf.FrameBuffer(p1, 8, 8, framebuf.MONO_HLSB) # i am using RP2040, use default I2C i2c = I2C(1, freq=400000) # create display object ol = SSD1306_I2C(128, 64, i2c, addr=60) ol.fill(0) ol.show() # erase # row of symbols ol.blit(fb0, 10, 10) ol.blit(fb1, 20, 10) ol.blit(fb0, 30, 10) # number followed by symbol ol.text("32.1", 20, 20) ol.blit(fbuf0, 52, 20) # another row of symbols ol.blit(fb0, 10, 30) ol.blit(fb1, 20, 30) ol.blit(fb0, 30, 30) # number followed by symbol followed by unit ol.text("273", 20, 40) ol.blit(fb0, 44, 40) ol.text("K", 52, 40) ol.show() exampx.png (view on web) https://github.com/micropython/micropython/assets/3868608/d1d7c7f0-2e48-4bf4-a419-45cdc7929d58 — Reply to this email directly, view it on GitHub #14338 (reply in thread), or unsubscribe https://github.com/notifications/unsubscribe-auth/A5BIYK3UZU7NNJNKQEF72ILY6QZTDAVCNFSM6AAAAABGQNNI5GVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM4TCOBRHA2DM. You are receiving this because you authored the thread.Message ID: ***@***.***>

[bruno1950]

Hi, interesting suggestion but may be too difficult for a newbie. In fact, if - for example - I open font6.py I find a very long series of hexadecimal values and I have no idea which characters these values correspond to. How can I identify the correspondence ? If I had to remove from the font the character @ that I'm not using and replace it with the symbol ° how could I do ? And for a different font ? let's say font10.py ? Thanks

…

Il 22/04/2024 12:21 CEST Marcus Mendenhall ***@***.***> ha scritto: If you want to rebuild micropython, you could just make your own fork that hacks the display module font, and replaces some other un-needed character code with a degree-sign glyph. It's not too hard to do a custom build, even if you are just getting into it. — Reply to this email directly, view it on GitHub #14338 (reply in thread), or unsubscribe https://github.com/notifications/unsubscribe-auth/A5BIYKYCSLSJGSREGX3IMELY6TQC3AVCNFSM6AAAAABGQNNI5GVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM4TCOBXGA2TA. You are receiving this because you authored the thread.Message ID: ***@***.***>

[wangshujun-tj]

默认的ssd1306驱动字库只有chr32-127的字符，而且在mpy里面使用utf8编码，chr170，也不是单字节编码，这个显示处理还是比较麻烦的