Building a board of buttons/switches/etc. - Page 2 - Electronic Circuits Projects Diagrams Free

Mad_un · 12th September 2007, 08:08 PM

Hey

Nice project... i wouldnt have thought about doing something like this; i would
have just gone and brought something.

Instead of having all normal switches, why not have some LDR's so things turn on when hands or fingers are placed over them and turn off when they are removed. Obviously having lots of these will mean lots of different circuits but one or two sould be easy along with adding some novelty to the toy.

cpgoose · 13th September 2007, 02:30 AM

Quote:

Originally Posted by Andy1845c

The starter from a truck, 2 pillow block bearings and a heavy chunk of iron makes a nice vibrating motor that will shake the box on a quad axle gravel truck

Now that's what I'm talkin' about!

cpgoose · 13th September 2007, 02:31 AM

Quote:

Originally Posted by Mad_un

Hey

Nice project... i wouldnt have thought about doing something like this; i would
have just gone and brought something.

Instead of having all normal switches, why not have some LDR's so things turn on when hands or fingers are placed over them and turn off when they are removed. Obviously having lots of these will mean lots of different circuits but one or two sould be easy along with adding some novelty to the toy.

Hey, can you elaborate on the LDR? I'm not sure what that is, besides what you said about it working when you put your hand over them. I tried looking on Jameco, but I guess I'm looking in the wrong spot. Great idea!

**Krumlink** · 13th September 2007, 02:32 AM

I would also include some Blinky lights too. some Flashing LEDs are easy to hook up. Make sure you stay within the specs of the voltage.

Andy1845c · 13th September 2007, 03:03 AM

Quote:

Originally Posted by cpgoose

Hey, can you elaborate on the LDR? I'm not sure what that is, besides what you said about it working when you put your hand over them. I tried looking on Jameco, but I guess I'm looking in the wrong spot. Great idea!

An LDR is a Light Dependant Resistor or photocell. While the idea suggested would be cool, its going to complicate the project greatly.

http://en.wikipedia.org/wiki/Photoresistor

KE5KBG · 13th September 2007, 03:06 AM

I would get a large AC to DC transformer instead of a battery. That way he won't run it donw and it won't cost as much for all the batteries. Or find an old plug for a calculator or anything, you could use led with the lower voltage. You could get one of those electronic project boxes where he won't be pulling the wires and everything is enclosed.

cpgoose · 13th September 2007, 05:32 PM

Quote:

Originally Posted by KE5KBG

I would get a large AC to DC transformer instead of a battery. That way he won't run it donw and it won't cost as much for all the batteries. Or find an old plug for a calculator or anything, you could use led with the lower voltage. You could get one of those electronic project boxes where he won't be pulling the wires and everything is enclosed.

I have 2 things at the moment (on my desk): One is a power cable from a gateway laptop, and the other is a computer power supply. I remember in college we used to hook-up a car amplifier into the computer power supply and plug it into the wall so we could use it in the dorm (only a few times, though). Could I use one of those two items to power this?

Andy1845c · 13th September 2007, 05:44 PM

You could use the computer power supply, but its kinda big isn't it?

I can't say if the laptop cord would work or not without more info. Is there any ratings on it? Output voltage and current?

picasm · 13th September 2007, 07:00 PM

Quote:

Originally Posted by cpgoose

I have 2 things at the moment (on my desk): One is a power cable from a gateway laptop, and the other is a computer power supply.

I think you could just use battery power, all you need to do is build-in a timer (using a 555 chip) so that it turns itself off after about 5 minutes.
Turning it on would be done using a pushbutton press to start the timer,then it cannot be left on permanently.

cpgoose · 13th September 2007, 07:08 PM

Yea, I guess the computer PSU is somewhat big.

The laptop cord has a plug, what looks like a fuse, and then a black box piece. It says:

Gateway Model # ADP-50FB
AC Input: 100-240V AC, 60/50Hz 1.5A
DC Output: 19V 2.64A (with a line w/3 dots under it in between those two numbers).

Andy1845c · 13th September 2007, 08:23 PM

The gateway cord would work to a point. You need to decide exactly what is going to be on this board and how much current it will draw with everything on at the same time. The decide on how to power it and at what voltage.

With the cord, your going to want a voltage regulator in the circuit. It says the output is 19 volts, but with less then the rated current running though it, the voltage will be higher by quite a bit. And with the current draw constantly changing as the child plays with the various buzzers and lights, the voltage will be all over the place and make it hard to size resistors for your LEDs.

Mad_un · 15th September 2007, 12:41 AM

Quote:

Originally Posted by cpgoose

Hey, can you elaborate on the LDR? I'm not sure what that is, besides what you said about it working when you put your hand over them. I tried looking on Jameco, but I guess I'm looking in the wrong spot. Great idea!

Like andy1845c said, an LDR is a type of resistor. However, unlike a conventional resistor which has a relatively fixed value, an LDR’s resistance changes depending on the intensity of light hitting it. It can be used in conjunction with several other components to produce a circuit (ill find and example later) which senses the intensity and triggers an output where appropriate.

Here is a LDR http://www.rapidonline.com/productin...moduleno=29399

A draw back I just thought of though is, because it will be sensing a lack of light, it will turn on at night if the lights aren’t turned on.

cpgoose · 21st September 2007, 08:08 PM

Ok, can I just make sure I'm on the right track here? I've done more research, etc, and I'm starting to doubt that this can be done without having a massive power supply (like a computer PSU).

Let me just start basic (see attached). Let's just say I have 4-AA batteries connected as power (and they're 1.5v each). Then, if I use these LEDs (see link below) which say they're 2.0v, would this diagram work ok?

http://www.radioshack.com/product/in...t&tab=features

**Nigel Goodwin** · 21st September 2007, 09:18 PM

No, because the batteries are in parallel, giving only 1.5V - it's also ABSOLUTELY ESSENTIAL that you have current limiting in series with the LED's, like a resistor.

cpgoose · 24th September 2007, 04:30 PM

Ok, so if the LEDs were only 1.5v, then this diagram should work since my power source is putting out 1.5v, right?

And can you expand a bit on the resistors? Would I have to put one before each LED, or just 1 before the set of 4? I'm assuming this is to make sure they only receive a max of 1.5v and no more?

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12th September 2007, 08:08 PM	(permalink)
Mad_un	Hey Nice project... i wouldnt have thought about doing something like this; i would have just gone and brought something. Instead of having all normal switches, why not have some LDR's so things turn on when hands or fingers are placed over them and turn off when they are removed. Obviously having lots of these will mean lots of different circuits but one or two sould be easy along with adding some novelty to the toy. Last edited by Mad_un; 12th September 2007 at 08:19 PM.

13th September 2007, 02:32 AM	(permalink)
Krumlink	I would also include some Blinky lights too. some Flashing LEDs are easy to hook up. Make sure you stay within the specs of the voltage. __________________ MechTronics World of Warcraft is a disease

13th September 2007, 03:06 AM	(permalink)
KE5KBG	I would get a large AC to DC transformer instead of a battery. That way he won't run it donw and it won't cost as much for all the batteries. Or find an old plug for a calculator or anything, you could use led with the lower voltage. You could get one of those electronic project boxes where he won't be pulling the wires and everything is enclosed.

13th September 2007, 05:44 PM	(permalink)
Andy1845c	You could use the computer power supply, but its kinda big isn't it? I can't say if the laptop cord would work or not without more info. Is there any ratings on it? Output voltage and current? __________________ This message transmitted on 100% recycled electrons

13th September 2007, 07:08 PM	(permalink)
cpgoose	Yea, I guess the computer PSU is somewhat big. The laptop cord has a plug, what looks like a fuse, and then a black box piece. It says: Gateway Model # ADP-50FB AC Input: 100-240V AC, 60/50Hz 1.5A DC Output: 19V 2.64A (with a line w/3 dots under it in between those two numbers).

13th September 2007, 08:23 PM	(permalink)
Andy1845c	The gateway cord would work to a point. You need to decide exactly what is going to be on this board and how much current it will draw with everything on at the same time. The decide on how to power it and at what voltage. With the cord, your going to want a voltage regulator in the circuit. It says the output is 19 volts, but with less then the rated current running though it, the voltage will be higher by quite a bit. And with the current draw constantly changing as the child plays with the various buzzers and lights, the voltage will be all over the place and make it hard to size resistors for your LEDs. __________________ This message transmitted on 100% recycled electrons

21st September 2007, 09:18 PM	(permalink)
Nigel Goodwin	No, because the batteries are in parallel, giving only 1.5V - it's also ABSOLUTELY ESSENTIAL that you have current limiting in series with the LED's, like a resistor. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

24th September 2007, 04:30 PM	(permalink)
cpgoose	Ok, so if the LEDs were only 1.5v, then this diagram should work since my power source is putting out 1.5v, right? And can you expand a bit on the resistors? Would I have to put one before each LED, or just 1 before the set of 4? I'm assuming this is to make sure they only receive a max of 1.5v and no more?