Electrical Engineering V2

[Perl]

[QUOTE=LoneWolf_Recon;44756306]After some Google digging, this might be of use (Couldn't find a Linux equivalent):

[URL]http://www.ollydbg.de/[/URL]
[URL="http://www.codeproject.com/Articles/670373/Csharp-Read-Write-another-Process-Memory"]C# Implementation[/URL][/QUOTE]

It's very unlikely that the RPM is static, which is when further reversing and signature scanning is necessary.

[Nutcake]

[QUOTE=Perl;44756143]You could make a tool that uses signature scanning to find the proper location.
Add me on steam if interested.[/QUOTE]

Thanks, but no thanks, I don't really care about that project anymore, since it's such a hassle to set up all those LEDs and it doesn't really add anything to the game.

[sambooo]

Your way sounds so much more appealing than having to use X-Sim, I might give that a go.

Right now it maps 0-20000 RPM onto the range of an uint32 but not in entirety and I just have to guess with the sliders to calibrate the damn thing.

Perl, I don't have enough time to spent hours on end hacking away right now because I have finals in 2 weeks but that does sound interesting and preferable to what I'm doing at the moment. I might talk to you in future if you don't mind!

[editline]8th May 2014[/editline]

Also I won a £50 Amazon voucher today, just three days after I spent £44 on Amazon :(

[Perl]

[QUOTE=sambooo;44756729]Your way sounds so much more appealing than having to use X-Sim, I might give that a go.

Right now it maps 0-20000 RPM onto the range of an uint32 but not in entirety and I just have to guess with the sliders to calibrate the damn thing.

Perl, I don't have enough time to spent hours on end hacking away right now because I have finals in 2 weeks but that does sound interesting and preferable to what I'm doing at the moment. I might talk to you in future if you don't mind!

[editline]8th May 2014[/editline]

Also I won a £50 Amazon voucher today, just three days after I spent £44 on Amazon :([/QUOTE]

Sure, no problem.
I don't mind helping people out on subjects I know. (not that I'm a reverse engineering expert, but I know enough for this kind of stuff)

[Zero-Point]

Wanting to mess around with this Arduino and the IDE crashes immediately on startup.
Feels bad, man.

[LoneWolf_Recon]

[QUOTE=Zero-Point;44757000]Wanting to mess around with this Arduino and the IDE crashes immediately on startup.
Feels bad, man.[/QUOTE]

The IDE is rather lacking for the experienced, try building with winavr or tutorials like [URL="http://www.vascop.com/compiling-and-uploading-arduino-programs-without-the-ide.html"]this[/URL] or [URL="http://www.linuxcircle.com/2013/05/15/programming-and-uploading-arduino-sketch-without-ide/"]this[/URL]

[Leestons]

[QUOTE=Zero-Point;44757000]Wanting to mess around with this Arduino and the IDE crashes immediately on startup.
Feels bad, man.[/QUOTE]

I use sublime text and stino
[url]http://forum.arduino.cc/index.php?topic=138014.0[/url]

[Zero-Point]

[QUOTE=LoneWolf_Recon;44757024]The IDE is rather lacking for the experienced, try building with winavr or tutorials like [URL="http://www.vascop.com/compiling-and-uploading-arduino-programs-without-the-ide.html"]this[/URL][/QUOTE]

Aw man that looks like it requires Linux ju-ju, and I'm fresh out.

[paindoc]

[QUOTE=scratch (nl);44755084]seeing how we're talking about peltiers, I got mine two days ago

[t]https://dl.dropboxusercontent.com/u/43645231/photos/electro/2014-05-08 17.30.54.jpg[/t]

big ass heatsink does help I assume as this thing cools like a motherfucker. I didn't do the thermal paste so well though as the outer corners aren't covered, and it's hard to get the plate off due to suction forces :v:

[editline]8th May 2014[/editline]

and that's on 9 V. can't wait to try it on 12[/QUOTE]

Peltiers are fun I may have to lift one out of our 5 pack in engineering for experiments in ghetto air conditioning this summer, since my dorm doesn't have air conditioning and doesn't allow you to get your own units.

Solving this issue would be wayyy easier if I had a working 3D printer, I would just redesign an external heatsink for the MOSFET and vreg.

Also, vreg is receiving 12v 6a as well

[alexaz]

[QUOTE=paindoc;44758716]if I had a working 3D printer, I would just redesign an external heatsink[/QUOTE]

Uhh what? ABS/PLA isn't a good thermal conductor. It won't work. Your mosfet might even melt your 3D printed heatsink. You could CNC an aluminium one tho.

[DrLuke]

[QUOTE=scratch (nl);44755084]seeing how we're talking about peltiers, I got mine two days ago

[t]https://dl.dropboxusercontent.com/u/43645231/photos/electro/2014-05-08 17.30.54.jpg[/t]

big ass heatsink does help I assume as this thing cools like a motherfucker. I didn't do the thermal paste so well though as the outer corners aren't covered, and it's hard to get the plate off due to suction forces :v:

[editline]8th May 2014[/editline]

and that's on 9 V. can't wait to try it on 12[/QUOTE]

The same principles as for computer heatsink applies to peltiers: you don't NEED 100% coverage. What you need is a solid connection wtihout any air bubbles between the two. That mean, put a little pea in the center, slowly press down the Peltier, and then don't move it too much. That will be enough to transfer all the heat reliably, given that the heatsink is big enough, and kept cool enough.
You definitely want the fan blowing INTO the heatsink in your setup!

[woidoi]

[QUOTE=DrDevil;44761571]The same principles as for computer heatsink applies to peltiers: you don't NEED 100% coverage. What you need is a solid connection wtihout any air bubbles between the two. That mean, put a little pea in the center, slowly press down the Peltier, and then don't move it too much. That will be enough to transfer all the heat reliably, given that the heatsink is big enough, and kept cool enough.
You definitely want the fan blowing INTO the heatsink in your setup![/QUOTE]

yeah, fan blows in and I did put down a blob and squeeze. I did slide it around a bit to spread the stuff around though, but it seems to work fine.

[Tezzanator92]

I need to build a power supply for my Playstation 2 and LCD screen that is attached for use in the car. So I need to build a power supply that can drop the 10-15V Input to 7.5V at around 5A.

I have a cheap chinese power supply that came with a Ps2 car kit off ebay but I don't trust it as far as I could throw it so I want to gut it, use the casing and cable and put my own in there. It makes a REALLY horrible high pitched noise when it's under any extra load (Controller vibrates, CD spins up, load souns Etc.) - It's probably harmless but it cost £1.50, I do not trust it to not destroy my PS2!

I've been reading the datasheet for the LM138 adjustable voltage regulator which seems to be able to give me a minimum of 5A and a typical 8A so with some headroom. But my past experience tells me a regulator is going to be kicking out a fair bit of heat dropping 12V to 7.5V at such high currents.

Is a DC-DC converter what I'm looking for instead?

[DrLuke]

[QUOTE=scratch (nl);44761647]yeah, fan blows in and I did put down a blob and squeeze. I did slide it around a bit to spread the stuff around though, but it seems to work fine.[/QUOTE]

Don't do that. You DON'T need to spread it around.

[No_Excuses]

That would be the LM138's current limit. Somewhere from 5 to 8A. The minimum load current is around 3.5mA.

So at maximum the car supplies around 14V, -7.5V = 6.5V @ 5A max = 32.5W dissipation which is a heck of a lot to deal with.

A DC-DC buck converter requires more parts and complexity but the power losses are minimal compared to a voltage regulator.

[editline]9th May 2014[/editline]

And speaking of power dissipation...back in the day when I knew nothing about electronics I built a Class A amplifier from schematics online that dissipated 100W per channel. It was my first electronics project which I did for a high school project.

[thumb]http://i.imgur.com/PCPABJK.jpg[/thumb]

The heatsink worked great. 6lbs of aluminum and some fans will do it... The amp itself never worked quite right. Has some oscillations and other problems. It was my first project and a big fat failure and I've always hated it. Some day I'll go back and scratch design my own AB amp and make up for it.

[thumb]http://i.imgur.com/beWZ2AY.jpg[/thumb]
[thumb]http://i.imgur.com/r41o7DR.jpg[/thumb]
[thumb]http://i.imgur.com/6gPSn8z.jpg[/thumb]
[thumb]http://i.imgur.com/yKDk1zz.jpg[/thumb]

[editline]9th May 2014[/editline]

It's actually kinda embarrassing to post that. Like what was I even thinking? No prototyping whatsoever...or calculations. It was just the second time I picked up a soldering iron and the only electronic thing I had built before that was a pair of crossovers.

[Tezzanator92]

I love it, Amplifiers are right up my street even if they do look like shoe boxes with heatsinks poking through - It adds to the look :)

I really want to get into designing some more intricate audio electronics, I've built basic preamps and buffer circuits (DI Boxes and the like) and know enough to debug and repair audio gear. Maybe when I finish my degree I'll devote the time to learning a bit more.

I think for simplicity sake I'm going to grab one of these ready built PCBs off Ali:
[url]http://www.aliexpress.com/item/DC-DC-15A-Adjustable-High-Power-Low-Ripple-Synchronous-Rectification-Step-down-Buck-Module-98-Efficient/1560609423.html[/url]
Massively over-specced in the current capability department but being a cheapo chinese built-to-a-price unit I don't think that's necessarily a bad thing?

I actually got confused with previous project and it's 8.5v I need, not that it matters.

[Chryseus]

[QUOTE=No_Excuses;44762424]It's actually kinda embarrassing to post that. Like what was I even thinking? No prototyping whatsoever...or calculations. It was just the second time I picked up a soldering iron and the only electronic thing I had built before that was a pair of crossovers.[/QUOTE]

Everyone makes mistakes even with proper planning.
It still looks quite nice even if it doesn't work properly, although I would have suggested the more complex parts be on copper clad rather than wood.

[sambooo]

Now featuring shift registers:
[t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_171045.jpg[/t]

[DrLuke]

[QUOTE=sambooo;44764281]Now featuring shift registers:
[t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_171045.jpg[/t][/QUOTE]

Post your code please

[Leestons]

Blew a fuse in my multimeter :( God dammit.

[sambooo]

[QUOTE=DrDevil;44764706]Post your code please[/QUOTE]

Uses a small amount of boilerplate from a tutorial on the Arduino website, but it's pretty simple anyway:

const int latchPin = 8;
const int clockPin = 12;
const int dataPin = 11;

void setup() {
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  Serial.begin(9600);
  while(!Serial);
  Serial.println("reset");
}

void loop() {
  if (Serial.available() > 0) {
    byte count = Serial.read();
    if ('0' <= count && count <= '9') {
      count = count - '0';
      illuminate(count);
    }
  }
}

void illuminate(int number) {
  byte bitsToSend = 0;

  digitalWrite(latchPin, LOW);
  for (int i = 0; i < number; i++) {
    bitWrite(bitsToSend, i, HIGH);
  }

  shiftOut(dataPin, clockPin, MSBFIRST, bitsToSend);
  digitalWrite(latchPin, HIGH);
}

[editline]9th May 2014[/editline]

The input from my pc isn't really 'code' that I can post because the software is shit and you do maths with a fucking gui.

[Zero-Point]

[QUOTE=sambooo;44764281]Now featuring shift registers:
[t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_171045.jpg[/t][/QUOTE]

I wish Radioshack sold shift registers. They'd have a huge markup, yeah, but at least I wouldn't have to wait a week or so to get one. They already sell 4-pack logic bags with AND, NAND, OR and NOT chips in them, so it would be a huge compliment to their Arduino/Parallax merchandise they currently sell.

[JohnnyCrazy]

Bought a startkit today to do some experimenting :3

[IMG]http://ecx.images-amazon.com/images/I/516WfICIppL.jpg[/IMG]

Let's see what you can do with it

[TCWilliamson]

[QUOTE=Zero-Point;44765403]I wish Radioshack sold shift registers. They'd have a huge markup, yeah, but at least I wouldn't have to wait a week or so to get one. They already sell 4-pack logic bags with AND, NAND, OR and NOT chips in them, so it would be a huge compliment to their Arduino/Parallax merchandise they currently sell.[/QUOTE]

Ooor you could just order say 50 pcs from farnell or mouser....

[url]http://uk.farnell.com/texas-instruments/cd4094be/ic-8bit-sipo-shift-register-dip/dp/2257361[/url]

[sambooo]

[QUOTE=johnnyaka;44765482]Bought a startkit today to do some experimenting :3

[IMG]http://ecx.images-amazon.com/images/I/516WfICIppL.jpg[/IMG]

Let's see what you can do with it[/QUOTE]

I bought a starter kit from Amazon too, if that is anything like what I got you'll probably have a painfully short supply of resistors and a switch that doesn't fit the breadboard they gave you. Also this lovely unusable blunder: [t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_213122.jpg[/t]

[DrLuke]

Buy Female-Female or Female-Male jumper cables.

[sambooo]

I've got a bigger breadboard now so it's not a problem anymore. Still short of resistors though, I ordered some earlier so that'll be fine soon enough anyway.

[JohnnyCrazy]

[QUOTE=sambooo;44766210]I bought a starter kit from Amazon too, if that is anything like what I got you'll probably have a painfully short supply of resistors and a switch that doesn't fit the breadboard they gave you. Also this lovely unusable blunder: [t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_213122.jpg[/t][/QUOTE]

It's coming around Monday, so I will report back how the quality is.
Hopefully not too bad. I read the jumper cables aren't very good.

[TCWilliamson]

[QUOTE=sambooo;44766210]I bought a starter kit from Amazon too, if that is anything like what I got you'll probably have a painfully short supply of resistors and a switch that doesn't fit the breadboard they gave you. Also this lovely unusable blunder: [t]https://dl.dropboxusercontent.com/u/30829668/Phone%20photos/IMG_20140509_213122.jpg[/t][/QUOTE]

Here is a good solution. I own loads of breadboards, if you just take 2 and stack them like this it will fit most things:

[img]http://i.imgur.com/Q5elkSTm.jpg[/img]

[paindoc]

[QUOTE=alexaz;44761212]Uhh what? ABS/PLA isn't a good thermal conductor. It won't work. Your mosfet might even melt your 3D printed heatsink. You could CNC an aluminium one tho.[/QUOTE]

Redesign an enclosure for our new heatsink addition that Im adding to the back of the project, or change some of the elements of the original design completely. the whole cooling unit enclosure and cabinet are 3d printed in ABS