Had a great day on my blacksmith course making a Ram’s head fire poker at Adrian Wood’s Forge, I would highly recommend it.

I went back for a second course after making a dragon coat hook last year, course which was part of my 50th birthday presents.

Tentacle sketch

I got a cheap SPI TFT ST7735 Display module with SD Card reader off ebay, it had an unusual number of pins on the back.

It took a while searching about on the internet and some head scratching to find a library and work out what connected to what on the Pico.

This is what I found, and worked out.

Using that information I was able to put together this library based on a few others I found and a few test programs.

Something I did a few (8) years ago on the Arduino to display two-digit numbers on a 8x8 LED matrix, this is an update to do the same in Micropthon.

Numbers have been defined to 3x5 pixels, so for a two-digit number it fits into 8x5 LED grid with spacing, saving some LED Matrix space.

The code for this can be found here numbers.py

Just a short bit of code to test a DHT11 temperature and humidity sensor module.

This version has just three pins VCC, GND and data, so easy to connect and use with the DHT library.

dht11.py.

Found a LED Matrix with a Max7219 in my parts bin (box of random electronics in the garage) so looked into getting it working with the Pico and MicroPython.

This is an example why I love open source. The original library I found was functional but sparse, last committed to 4 years ago. There were a few forks, most not much activity. One had been active recently and had some major improvements in functionality so switched over to that fork. https://github.com/enchant97/micropython-max7219

Stumbled across a Python script to run a Mandelbrot set in ASCII in Python so I thought I would see how it ran on the RaspberryPi Pico.

After tweaking it slightly from the source it ended up like this mandelbrot.py

This results in the following;

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                     ...................................,,,,,,,,,,,,,,,,,.......................................................
                    ..........................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,.............................................
                  .....................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,......................................
                 .................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,----------,,,,,,,,,,,,.................................
               ...............,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,---------:i;;::::-------,,,,,,,,,.............................
              .............,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,----------:::;ih$+;;::::-------,,,,,,,,,..........................
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                 .................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,----------,,,,,,,,,,,,.................................
                  .....................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,......................................
                    ..........................,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,.............................................
                     ...................................,,,,,,,,,,,,,,,,,.......................................................
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I amended the code to update the OLED I was using in the temperature sensor tests mand_oled.

Have been tinkering with temperature measurement using the Raspberry Pi Pico.

First with the internal temperature sensor and then using a TMP36 temperature sensor externally.

I wrote two classes to access these and return the reading.

• Internal Temperature
• External Temperature

Here is an example using the two sensors together temps.py

You will need to upload the two classes to the Pico first in a library sub-directory.

Here is how you would wire it up on a breadboard tmp36.fzz

Some components arrived from AliExpress recently so been able to play with an I2C OLED display with my Pico W.

Hello World Test

Code of this is here https://github.com/alastairhm/pico_w/blob/main/i2c_scan.py

And also used here to display the IP address after connected to the wifi https://github.com/alastairhm/pico_w/blob/main/wifi_oled.py

Next thing I’ve been playing with is internal and external temperature sensors, I will post about that soon.

Flickr Album for Inktober 2022