Hi Vladokv,
  it's not too difficult:

1) H2 generating jar:
 - Jar with a lid. Glue some (50cm) tube in top of lid.
 - half fill jar with water, and a little KOH, and some aluminium foil. It starts bubbling - pure H2.
 - Put lid on jar... Let H2 replace all air in the jar and tube...

2) Spark-chamber:
 - Small plastic bottle with bottom cut off & lid on.
 - 2 electrodes fixed into place (tape/glue etc), coming down through the open bottom of the bottle, or glued through the cap.
 - Electrode wires connected to HV supply.

3) Bowl of water:
 - Put spark-chamber bottle in water bowl - until it's full of water
 - Put tube from H2 Generator under bottle
 - Pure H2 gas fills bottle. Water seals it off.

Of course, the whole process is fraught with danger!
 - KOH is nasty
 - If air mixes with H2 - it will explode with the spark
 - It would be a good idea to shield the apparatus - by putting it in a plastic box for example...
 - etc. etc...

What do you think?


Regards, Tim