Electronics Electronic Circuit Help Needed, Stargate style power switch/system

Right after being stunned into awe and amazement
by the modding/project logs on this site I want to have a go.

Starting off small I want to create a switch system in the style of 7 buttons pushed in sequence in order to turn on the pcb (Get the stargate idea now)
Now while creating DHD would be kool i have no modding skills and i really want to start small.

So ill have a small panel on my desk (as I dont feel confident modding my new case just yet anyway) with 7 big plastic/acrylic push switches (with stargate sg1 style symbols on them) not in order obviously. Then I want to push each switch so that an LED comes on to light up the symbol and allows me to push the next correct symbol in the sequence and so on and obviously when I push the 7th symbol (chevron 7 locked ) it functions as the pc power on switch and obviously turns on the pc on. Ideally I would like the leds to stay on for about 20s then all turn off after pushing the seventh symbol.

Couple of explanations then my questions. I want in its own unit on my desk so i dont have to mod my case for the moment anyway. As such It will have its own battery pack (and that i could think of a way of powering it off the psu) It will have a master switch so i can turn it off when the pc is started to save battery

Now im not really sure how to do the electronics the achieve the effect I want. Ironically a couple of years ago back in my old gcse system nd control class i cud of done this with a pic and the crappy pic logicator software but alas i do not have the software nor the programing device.

So any idea guys? I will do my own research later Got to clear up my room and makeway for my new gaming pc!

Thx
Martin/Fused

 

I think that the easiest method would be to use a microprocessor. I'm sure that your goal could be accomplished with relays and ICs, but it would require a custom designed circuit that you couldn't really adjust without adding new components.

You could route the PC's power button directly to the DHD so that you can skip all the steps if necessary. That might make things a bit easier for the time being as all you would have left to do is construct a circuit that turns on 7 LEDs in sequence.

I think that this is described in a few other threads.
http://forums.bit-tech.net/search.php?searchid=2335736

 

y don't you just have 6 switches and one momentary switch in series so that as you switch the first 6 switches the leds light up and then when you press the last switch its leds lights up as long as you hold it down and the pc starts up

you will have to use some transistors to allow the leds to be powered and you will have to turn off the first 6 after


not sure if this would work cos i`m not all that good with electronics

 

That's probably the simplest way of doing it, but then he's going to have to flip 12 switches everytime he wants to turn on the PC.

Hmm.

If he does it your way, with 6 SPDT toggles, he can throw in another SPDT switch to disengage all 6 switches at the same time. Then, when he wants to turn the PC on next time, he can flip the 6 switches and then turn them off by flipping the SPDT the other way. And if he didn't want to go through the cycle, he could bypass it all by simply pressing the momentary.

 

yeah sounds good

 

If I am reading his post correctly, he wantsthis to ba combination lock. The schematic above would just allow the machine to turn on without having to know the combination. He said the symbols would obviously not be in order. That suggests that he wants this to be a puzzle.

I think a micro controller is the best solution. I am not very good with the electronics, but the programming would be fairly simple. I am thinking (and someone smarter please correct me) an 8 I/O controller. The 7 buttons would be connected to control the conbination and the 8th would be used to control the LED's with some kind of matrix and global reset. But what do I know.

 

Sounds like a excellent use for a basic stamp pic!

 

i think 7 inputs to a PIC plus one output to a relay to connect the 2 pins together that turn the computer on would be the easiest. and if your monitor has usb output, you could power it thru that. this way your monitor would be on for the circuit to work, thus making it your master switch. and it would get rid of the need for a battery.

for the PIC, you could just poll all the buttons and wait for the correct order (there might even be an easier way). fairly simple programming.

 

Thanks guy after some research and reviewing what you guys said here i have a few question:

Does anyone know where you can get PIC programing software/ and the pic programing device? (preferably from a UK source)
(I did think I could do it with a pic program been a while since ive used one at school)

How could I turn a usb connection from a monitor to power the circuit board?

 

you could always get a really cheap electronic combination pad then reroute some of the wires to runes

you could have 10 runes (buttons) one for each number on the combination pad and then a center button like on the DHD's which is linked to the enter button so then you have to hit the correct 7 runes in order and then the center button

 

usb has 4 lines going to it, 2 are data lines, one is +5 volts and the other is GND. It can source up to 500mA. so if your monitor has a usb output on it, and is powered on, the usb ports have +5V power because the monitor has its own power supply separate from the computer (but no data can be sent or received because the computer is off)

so to get the power to the circuit board, all you would need is a usb cable and a usb connector on your circuit board. ignore the 2 data lines and pull the +5 and GND from the cable.

wikipedia might do a better job of explaining it then i just did...

 

i.e. get a USB cable, cut the appropriate end off, use the red and black wires.

 

Right im quite set on the PIC idea but I still not quite sure how to get all the necessary stuff to program a PIC. I think ive found some PIC programers on Maplin but i dont have any software yet. And Ive never used anything but an educational flowchart system software to write a program for a PIC. Is it hard to learn the raw code to program a pic? Can anyone recommend a good site/book to learn from? (and software to use to write it in)

On the rest of the project its slowly coming together in my mind, just at the moment how to make the buttons for the best look when finished (Orange UV reactive acrylic when uv leds undernearth to illuminate the symbol on each button/key)

One last thing will the usb from monitor still work if the monitor is in standby mode? Although I dont have a usb monitor yet im my experience all monitors go into standby until the recieve a signal from a pc? (I know they have power obviously just wondering if it still goes to the usb ports in standby mode)

Thanks for all your help so far guys