?? Why not? Before the load, and the voltage drop reduces the available power to the load. Every project I’ve seen that used transistors like switches puts the transistor between the load and GND.
Examples:
http://www.kpsec.freeuk.com/trancirc.htm
http://www.allaboutcircuits.com/vol_3/chpt_4/2.html
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/transwitch.html
Putting in a PNP would leave it constantly on because of the pull down resistor on the base pin.
I’ve got a bunhc of bad alligator clips, so I can’t do a whole lot right now.
That circuit, even without the 20k resistor should power the IC, but the logic won’t work properly. You’d have to start adding diodes on each input to the inverter to match the voltage loss.
Another choice is to repeat the transistor switch with PNP transistor. Your best bet, honestly, is to use the transistor to power the coil of a relay, and have the relay be a true switch for the IC. Measure the DC resistance of the coil yourself, most relays are about 300 ohm, and therefore use about 15 mA from the batt. For a digital only circuit, that current drain would be excessive; here you are powering tons of LEDs, so I assume you’ve got current to spare.
Using your PIC above, you would eliminate the 20k resistor. I would also consider changing the 5k for a 2.2k or 1k. The emitter and base wiring is the same. The collector would go to one side of the relay coil. The other side of the coil goes to 5 volt(+). You you wire from the 5 volt(+) to the common of the relay. Normally open goes to Vcc of the IC. The IC shares the common power ground. Done, clean grounds.
Here ya go:
Trust me, it’ll work. One of my own sticks uses the exact same circuit.
The first of the 3 links you posted shows a protection diode on a relay coil(about halfway down the page). Feel free to add one to the circuit.
I don’t understand what you’re trying to say here. The inverter logic works just fine when connected to a PSX; TingBoy’s youtube clip shows that pretty well.
Okay, let’s say we pull the 2n2222 that’s there and replace it with the equivalent PNP. If the transistor allows current to pass when the base pin is connected to ground, how will it be able to tell when it’s plugged in? We need the battery negative terminal and ground connected for the inverter to work right. How can we get the base pin to be connected low when plugged in, and not when unplugged? We could pull it high with a resistor, but if we’re using batteries the batteries would run dry if left unplugged for a few days. Batteries were included in the schematic to run the LEDs so the LEDs could be as bright as anyone could want without worrying about pulling too much current and blowing fuses.
I’m just not seeing what the relay gains us. If the transistor can control current to the relay, then why can the transistor control the power going to the inverter and/or LEDs?
The transistor is a switch with a voltage loss, that’s the problem.
Use a relay and you’re done.
If you use transistors, you need to change it so that all grounds are connected directly together.
hi, noob here, how do I lock down to 100ma so led’s don’t use more and end up shutting down the device? I have a home-made halogen light with a usb connection which works when connected to the pc, but not when connected to a usb plug - what you said might be the reason/
Back to the led mod - do I just put a resistor in there somewhere lock down to under 100ma?
Ok here’s the finished product. Thanks for the help with this, guys. I don’t know why I picked this project for my first stick, especially since I’ve never soldered, used power tools, etc.
[media=youtube]m4WwXLUZYTI"[/media]
Woooowww, nice.
Very nice. What color LED’s did you use? They look blue.
andre the giant has a posse
Nice job! I’m glad the guide was put to good use =D
Thanks Ting. The inside is a total rat’s nest but hopefully I won’t have to go in there for a long while. The ipac VE powers the whole thing no problem so I don’t have to use batteries. Hanaho Games is right by my house so they sold me the case for $20. Note: Hot Rod cases don’t take Sanwa or Semitsu parts. I had to rout out the joystick beds and each button hole with my dremel and drill separate holes. Spent a lot of money, spent a lot of time… It was worth it.
@ wiki
I used Blue Super Bright LEDs that I picked up on ebay here. They come with resistors which is nice if you had to go out and get those separately.
Next I think I’m going to use fluorescent wiring in a plexiglass box and use UV LEDs. That would be siiiiiicccckkkkk.
Great job. If you wanted to make the stick LEDs light-up as well, grab a 74XXX20, where XXX is what chip family you’re already using. It has 2 four input NAND gates. Wire the direction lines to the inputs, and the output to that stick’s LED, and it’ll light up when not in neutral. One chip can do both sticks
That’d be neat.
Yeah kaytrim, I still don’t get if you don’t need an external source or not, since you mentioned the converter, will it work on just straight up on the PS2?
If so, you think you can sell just easy to install versions of the board? Ones where I just have to connect the wires from the pad to the board, and LEDs to the board.
You mean like the board I have in this case? :wgrin: This one runs 10 LEDs. I’ll check with ZeroX and see how the LEDs work on his PS2.
http://i228.photobucket.com/albums/ee314/KaytrimsKustoms/ZeroX/100_3226.jpg
Here is another one for 6 LEDs.
http://i228.photobucket.com/albums/ee314/KaytrimsKustoms/R-Jive/100_3236.jpg
Report from ZeroX is that the LEDs work fine getting power from the Playstation.
Yeah, thats the stick I was referring too. The castlevania one right? And thats awesome, though if it used too much power hypothetically, would it blow out the controller ports on the first try or would it take a while? I’m assuming prolonged use? Like a fuse in the dreamcasts?
And, are you gonna sell easy to install versions of that circuit board so we can just plug them in and get the LED’s to work?
Also, what does that Pushbbutton inside the case do?
Most LEDs will work fine on a playstation. The reasoning behind using the batteries is so the voltage to the LEDs would always be the same known value. If you figure your resistors for 3.3v operation (Playstation) and then use a converter to use it on something else like PC USB, the voltage will be higher, the LEDs will be brighter, possibly too bright, and the current draw will be much higher. Dangerously so? Maybe not. I just liked the idea of the constant, known voltage, and almost no power draw for the LEDs from the attached console.
I have been thinking about selling the boards. I’ll figure up a price point and let you know. The pushbutton inside is the analog button for the pad.
I use resistors for a 5v power source. They are real bright LEDs so they are fine on 3.3V.
TTFN
Kaytrim
Awesome, i’ll be your first customer.
Where and Which LED’s do you guys get/use? Besides Dealextreme, I also read that some of you guys used “UV/Ultra Bright” Led’s? Any sources for that?
Edit: I Can’t find the other colors on Dealextreme.