LED mini light

additionally needed:
- piece of conductive wire to add to the switch so switch can complete the circuit when turned
- LED, e.g. 2.1 V , 20mA , up to 5mm diameter
- 2 hearing aid batteries size 13

assembly:
- put the 2 batteries in first, plus (+) at the top, small contacts (minus, (-)) at the bottom where the switch is
- put LED into the shade so the short end goes down straight to the switch
- bend LED leads with small pliers: The short end (cathode,(-)) goes down to where the switch is and it's lead should be "lying" at the bottom of the square hole.
- the long lead (anode,(+)) gets wrapped around the top and touches the top battery anode.
- add a piece of wire to the switch (picture) and insert carefully.

notes:
- in theory there should be a 40 Ω resistor added to make the batteries last as long as possible.
- frustration possible: the print may break when pushing the batteries in and adding the wire to the switch requires some fiddling