great,
C4 is there for making the led burn longer than the 20ms or am I wrong? EDIT: 470µF it's kinda big, no?
What is the use of D3?
1/4W resistors are okay to use I suppose?
While selecting the components I start wondering why not to use smaller battery? Like 2xAAA (3V) = upto 1500mAh, while a 9V Lithium = 1000mAh. The CD4013 can work in this range and I saw also 3V (buzzer) coils too, but what the rest of the circuit? Does it need some changes then?
Any tips for selecting the coil (the electro magnet for activating the small reed)? I was looking at
https://www.conrad.com and other places but I didn't find any small electro magnets, so my choice was to use the coil of an magnetic buzzer.
EDIT: I did some testing now with the coil and read switch. I used a 12V coil from a small relay (
AZ530-09-2) as electro magnet but the reed is not closing.
EDIT2: yes it does, see post 16/7
If I compare this with the small permanent magnet, this permanent has lot more power, it picks up a paperclip from about 10mm distance, the coil just can hold the paperclip when I hold it against.
So the coil from a buzzer will not do I suppose, any tips for an electro magnet with comparable power like a small (diam 5mm) permanent magnet? In the range 3-9V, max 15mm high, width can be more, 30+. I'm start wondering will the current of the coil still be in range for this circuit/battery?
Thanks for the fast replies, that is a real motivation for me.