Need help on a school project

[Leo Cor]

I am entering in a competition with a project I began last year. The regulations state that I can only use a 6V DC dry cell lantern battery, but i need a 12V DC circuit to move some selenoid valves that I will be using. I know basic electronics, and could build if given the schematics and parts lists, but I am looking for something that doesn't use very many IC's or coils, as there isn't a store in my town that carries a variety of electronic components.

I am also looking for a method to trigger an on off switch, but it needs to be very very sensitive, and it can't be momentary, as the devices need to remain active once activated. It wil be triggerd by a slowly moving billiard ball, and can't be to rigid as it would stop it. I can't seem to find sensitive push button toggles or toggle switches, and if anyone knows of a method with which to activate a device, such as a motor, and keep it running with a momentary switch, please let me know.

 

[IanP]

Let's start with power converson from 6V battery to 12V required by other devices ..
Here is a simple dc-dc converter, which, I am pretty sure, you can build from components readily available at your place ..
http://www.aaroncake.net/circuits/6-12conv.htm

And here: http://www.cpemma.co.uk/flipflop.html
you will find some examples on how to activate a motor with a momentary switch ..

Regards,
IanP

 

[silvio]

If you need 12v DC only for solenoid valves and the rest of the control circuit supplied by the lantern battery through an LDO regulator, you can use this voltage doubler at the bottom of this post:

Bear in mind that your solenoid valve requires a lower current (voltage) after activation, thus still being engaged. This way you can save your battery power.

If you need 12V DC supply for all the circuit or the solenoid valves need more energy, then the IanP's solution of using the convertor is a good ideea.

I am also looking for a method to trigger an on off switch, but it needs to be very very sensitive, and it can't be momentary, as the devices need to remain active once activated

Very sensitive:
**broken link removed**
**broken link removed**

 

[throwaway18]

You need to consider how much power you can get from the dry cell battery. You might find you can't get enough power to operate solenoids.

Silvo, that kind of touch switch control use the capacitance to earth of a large medium resistance human body. A small non-conductive billiard ball is unlikely to operate it.

Perhaps a light beam sensor could be used.

 

[silvio]

Silvo, that kind of touch siwtch control use the capacitance to earth of a large medium resistance human body. A small non-conductive biliard ball is unlikly to operate it.

Thanks throwaway18 for pointing out. I forgot he is using battery for power supply.
My mistake.

 

[throwaway18]

Depending on the rules of this competition, lego mindstorms or technical lego might be an easy source of sensors and custom moving parts.

 

[Leo Cor]

Thanks for the help, I am looking at the Flipflop that Ianp suggested, and I think I will use it. The only problem is that He suggests a dual flip flop, but only supplies schematics for using a single flip flop, and some kind of wierd grid thing that resembles a spreadsheet. IF anyone could convert this into a schematic for me, I would really appriciate it. http://www.cpemma.co.uk/flipflop.html

And if someone could point me at a how to or tutorial on how to wind inductors, and if someone could tell me a part number or something for the core and wire for Mouser Electronics (where I am ordering the parts from since alot of sites I've been to have recomended it, and since Radioshack is shit anymore) for the volt converter from Ianp (the other one provided by Silvo seems to be gone) http://www.aaroncake.net/circuits/6-12conv.htm

Any and all help is really appreciated.
Leo Cor