I made electrolysis of water at home, but I wanted to catch hydrogen so I made this. Design is bulky and this is because I am still working on this project. So tell me in the comments what should be improved. Read everything before starting this project. Feel free to ask me about something that you are not sure or I didn't mention.

Post processing:

1. Sand the areas that you can, but not too much.
2. Use something like epoxy resin on the inside to prevent water leaking.
3. Put stainless steel dowel pins in holes. If they don't fit, use 5mm drill to make enough clearance. If this still occurs, sand dowel pins but not too much.
4. Use glue that can be dissolved with acetone and glue dowel pins first, after that glue two bottom and top piece.
5. Connect some sort of DC power. Where you connect ground there will be hydrogen and on the voltage will be oxygen.

Bill of materials:

1. 2x Stainless steel dowel pins m5x30
2. Sandpaper
3. Epoxy resin
4. Glue that can be dissolved using acetone
5. Balloon for storing hydrogen
6. Some sort of DC power. Feel free to choose what you use. I recommend using 9V battery and crocodile clips, cause that is easiest and cheapest option you can get

!Disclaimer!

Always put safety first and wear proper protection to avoid damage to your body especially use mask and goggles. Also be careful playing with hydrogen, because you can burn yourself or your lungs may be damaged.