Whistle Flip Flop - laser trainer

[Alan Smithee]

Hi All,

My questions:

I was going to get the parts from Maplin, but I can't find 1/2 CD4013

The needs to run on batteries, but the circuit diagram has earth symbols -
can some explain this to me? please.

Laser keyrings cost about £10. A laser on its own costs about £25 - any
reason I can't pull one from the keyring?

My Story:
I wish to make a laser device that will "train" a golfer to aim correctly -
it's a xmas prezzy for my partners father. I must confess, I know very
little about electronics, although I have made a MIDI device for an atari
computer (Etched circuit board and all), but don't ask me how it worked !

Basically it's a box on the floor against the wall that emits a beam to a
putter face (which has a mirror on it). The target is to aim the putter
back at the device - the beam reflection against the wall indicates how
accurate the aim was. The laser will be controlled by a whistle controlled
flip flop switch. Here's the circuit diagram for a whistle flip flop that I
plan to use.

http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#whistle.gif

Thanks to anyone that can help

 

[Howard Henry Schlunder]

I was going to get the parts from Maplin, but I can't find 1/2 CD4013

Look for CD4013 instead. The 1/2 is not part of the part number, but an implication that only 1/2 of the IC is being used. The 4013 is a dual flip flop, meaning that it has two flip flops inside the same chip. As the schematic calls for only two 1/2 CD4013's, if you only have to buy one CD4013 chip.

The needs to run on batteries, but the circuit diagram has earth symbols -
can some explain this to me? please.

Those symbols are a ground reference voltage/node, but do not imply any connection to the earth. As most circuits online don't require a connection to earth ground, you will likely find an explicit comment with the schematic mandating connection to something earthy if the circuit needs it. For your case, simply attach all of the ground symbols to the same wire (or plane if you are making a multilayer PCB) and connect the negative terminal of your battery to it as well.

Laser keyrings cost about £10. A laser on its own costs about £25 - any
reason I can't pull one from the keyring?

Although I have no idea what comes with a £25 "laser on its own", I would definitely recommend using a key chain variety for your project. You may, however, find that removing the laser from its barrel is not a desirable thing to do. Laser diodes themselves don't give you a collimated laser point; you must have an appropriate lens which is properly positioned. In the laser pointer I tried to disassemble, the lens was screwed into the barrel, properly positioning it for operation.

Good luck with your project.

Howard Henry Schlunder