How to delete the old .NET SDKs

dotnet --list-sdks
dotnet --list-runtimes

Change the version and run:

version="3.1.29"
sudo rm -rf /usr/local/share/dotnet/sdk/$version
sudo rm -rf /usr/local/share/dotnet/shared/Microsoft.NETCore.App/$version
sudo rm -rf /usr/local/share/dotnet/shared/Microsoft.AspNetCore.All/$version
sudo rm -rf /usr/local/share/dotnet/shared/Microsoft.AspNetCore.App/$version
sudo rm -rf /usr/local/share/dotnet/host/fxr/$version

Matchbox FM-receiver "Golden Eagle"

Text

1.5V Project: Headphones Amp

1.5V Project: "NightBug"

Led booster with light sensor. Only a 1.5V battery is required. Current  < 10mA.

Homemade watercolor paint receipt

Watercolor receipt

Pigment:  2 teaspoons

Gum arabic: 2 ml

Water distilled (or boiled but cold): 1,5ml (add partly by 1 ml + 0,5 ml)

Glycerin (pharmacy): 1,0 ml (add partly by 0,5 + 0,5 ml + 0,5*)

Process:

- Put pigment into a plastic bag or any container. I used the "Yellow Ochre".

- Add gum arabic, 2ml. Mix the ingredients.
- Add part of water, 1 ml, and mix more.
- Add part of glycerin, 0,5 ml.

- Probably, the mixture will be quite thick, then add part of the water 0,5 ml – mix, and if you need more liquid consistency follow next with the part of glycerin 0,5 ml.

- Test the paint. Put a drop of paint, and stretch over the surface of the palette (but not on the paper). Let it dry for 10 minutes. There is should be barely noticeable shine at an angle on the paint surface. If it is completely matt and the next *0,5ml part of glycerine.

- Fill into a tube or cuvette.

- Left for a night, better two. Use it or fold it into the foil like I did.

Using these portions I made 5 ml of watercolor paint. (for two 2,5ml cuvettes)

How does it work?
Gum arabic – binder, or just glue for pigment. Glycerol molecule holds water thus paint always will be moisture and do not becomes completely dry. Also, glycerin affects the paint flow. 

(*Should try to add an Ox Gall -> flow)

Do not:
- Add too much glycerin. The paint will be too liquid, and not stable in the cuvette. Probably, you don't want to find that the paint has been peeled off and smeared the entire watercolor box.
- Add to less glycerin. The watercolor will not flow and becomes too dry and sharp like acrylic.
- Do not care about too much or less water. Excess water will evaporate. It becomes harder to control the amount of glycerin if there is too much water.

You have made a good paint if:
In cuvettes:
- It dries into solid viscous consistency but does not become completely dry and brittle.

In use:
- It is easy to moisture and picks up with a brush.
- It has a good flow on the paper.
- A dense layer of paint does not crack on the paper.