Please look at the last page of Nuts and Volts Column #6 as I suggested earlier. It has a schematic of your circuit. With the relay I suggested, the diode is built into the relay. The relay is designed for a +5V supply instead of the +12V shown in the schematic. The schematic diagram shows a 390 Ohm resistor. The 1K resistor will work fine in your case. An LPT output pin should work just as well as the Stamp pin. Usually the LPT pins cannot supply as much current as the Stamp I/O pins, but, in this case, it should be more than enough.
The ground for the transistor and the relay's 5V power source should be the same. The parallel port can't supply the +5V.
The diagram you posted is essentially correct. The +Supply has to be +5V. The ground connection has to be the same as the ground for the +5V for the relay and the ground for the Stamp or the parallel port. The relay connections you'll have to get from the relay datasheet. The link to that is on Jameco's webpage for the relay. The built-in diode has to be wired backwards. The cathode goes to +5V and the anode goes to the transistor's collector (and through the transistor to ground) so the diode will not conduct normally.
And I guess I have found the +5v supply. I discovered that the red wire from the powersuply to hdds, cdrom, etc inside my computer is about + 5. The yellow is +12v. The red wasn't exactly +5v. Does it matter if it is +4,5v?
I'm afraid that I don't understand what a diode is. I thought is was a small lamp, like a LED, but it seems that it is has to do with the relayoperation. But the relay has 4 pins and I guess I should connect 2 of them to the wire I wish to connect, and the 2 others to +5v suply and to the transistors C-pin
This relay is copied from the datasheet, and I guess it is connected like this, because there is a "+" symbol at the relay.
Read the Nuts and Volts Column I mentioned and look at the diagram I suggested!
Do not connect the relay the way you drew it. You'll damage something.
From the diagram you showed, pins 1 and 4 are the relay contacts. Pins 2 and 3
are the relay coil and diode. The "+" shows the end of the diode that should be
connected to the "+" power supply (the cathode). The other end (the anode)
should be connected to the collector of the transistor and, when the transistor
is switched on, to ground.
Be very careful connecting to your computer's power supply. It can provide very
high currents (like a small arc welder). Use a fuse in the wire connecting to +5V,
rated at no more than 1 Ampere. A fuse designed for automobile use will work.
Do a web search for "wiki diode" and "wiki relay". There are versions of the
Wikipedia in all sorts of languages. Here's a link to a description of diodes in
Norwegian: nn.wikipedia.org/wiki/Diode.
Ops, I forgot to move the text to the right place after writting it. I just wrote every word I needed, without moving them to the right position.
This was how I·tought to connect it:
And I will realy put a fuse between the relay and the suply.
Post Edited (Bjørn Tore) : 9/3/2008 2:14:37 PM GMT
The Guitar controller also have the whammybar.
There is 3 wires connected to the whammybar.
I guess the wire in the midle is a signal back to the guitar, because the wire (left) with red stripe seems to be ground, and the one to the right seems to be constant 1,61v. When I connect the digital multimeters COM to the left wire and V to the wire in the midle it shows 0.91 if the whammybar is in the main position, and the voltage drop when I start to move the whammybar. The voltage is 0,17v if I move the whammybar to the max position.
How can I build a wammybar replacement? I want to activate it with a on-off switch. 5 Wammys pr secound should be more than good enough.
Comments
The ground for the transistor and the relay's 5V power source should be the same. The parallel port can't supply the +5V.
I'm afraid that I don't understand what a diode is. I thought is was a small lamp, like a LED, but it seems that it is has to do with the relayoperation. But the relay has 4 pins and I guess I should connect 2 of them to the wire I wish to connect, and the 2 others to +5v suply and to the transistors C-pin
This relay is copied from the datasheet, and I guess it is connected like this, because there is a "+" symbol at the relay.
Do not connect the relay the way you drew it. You'll damage something.
From the diagram you showed, pins 1 and 4 are the relay contacts. Pins 2 and 3
are the relay coil and diode. The "+" shows the end of the diode that should be
connected to the "+" power supply (the cathode). The other end (the anode)
should be connected to the collector of the transistor and, when the transistor
is switched on, to ground.
Be very careful connecting to your computer's power supply. It can provide very
high currents (like a small arc welder). Use a fuse in the wire connecting to +5V,
rated at no more than 1 Ampere. A fuse designed for automobile use will work.
Do a web search for "wiki diode" and "wiki relay". There are versions of the
Wikipedia in all sorts of languages. Here's a link to a description of diodes in
Norwegian: nn.wikipedia.org/wiki/Diode.
This was how I·tought to connect it:
And I will realy put a fuse between the relay and the suply.
Post Edited (Bjørn Tore) : 9/3/2008 2:14:37 PM GMT
I got the package from Jameco today.
Do I need to use a clip on heat sink when solder the transistors, relays and resistors?
There is 3 wires connected to the whammybar.
I guess the wire in the midle is a signal back to the guitar, because the wire (left) with red stripe seems to be ground, and the one to the right seems to be constant 1,61v. When I connect the digital multimeters COM to the left wire and V to the wire in the midle it shows 0.91 if the whammybar is in the main position, and the voltage drop when I start to move the whammybar. The voltage is 0,17v if I move the whammybar to the max position.
How can I build a wammybar replacement? I want to activate it with a on-off switch. 5 Wammys pr secound should be more than good enough.