Electrical Engineering V3 - Developers

I was thinking about doing a small USB charger tester, to test how much current a charger can actually output, but that would be something for OSH Park, the board would be seriously minimal for that design.

[QUOTE=Leestons;48144514]I've thought about buying a kit a few times but always thought "I've never had the need for one, what would I do with it?"[/QUOTE] Testing audio equipment Checking the signal integrity of a circuit Radio with AM / FM modulation Driving switching converters Clock generation etc [QUOTE=nikomo;48144924]I was thinking about doing a small USB charger tester, to test how much current a charger can actually output, but that would be something for OSH Park, the board would be seriously minimal for that design.[/QUOTE] Make it more useful as a generic active load, couple of parallel MOSFETs and a nice heatsink you could easily handle 100W or more.

I've only ever used OSHPark but their service was top-notch and imho I like the purple. [t]http://i.imgur.com/uJs6wce.jpg[/t]

So I fucked up somewhere. Here is that dialing mechanism I built. It's two relays emulating a hook switch, a resistor and a capacitor. Externally it has a generic telephone bell and a rotary dial, plus inputs for the telephone line and +5 for hook switch control. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9619.jpg[/IMG] It doesn't work. :suicide: It will ring when someone calls the line but when taken off hook the telephone exchange does not detect it and continues to ring the line. The lack of a switch from 90v AC to 48v DC can be rather harmful to telephones and modems as you might expect... Meanwhile once you get it off hook to dial it will pulse the line but again, the exchange refuses to acknowledge that you did anything and drop the dial tone. I'm at a loss. Either the resistor or the capacitor are STILL incorrect values or I just don't know. Oh yeah. I somehow overlooked that while modern DTMF dialing will work when multiple devices are off hook, pulse dialing can't. :suicide: :suicide: I think I can get around this and continue to use the rotary dial by using one of those fancy pulse to tone converters.

AFAIK, Pulse Dialing is almost long dead/unsupported with most local exchanges.

It's still supported around here for some strange reason. Those adapters seem to be a gouge on ebay but of course from China [url=http://www.aliexpress.com/item/Old-dial-dial-telephone-dedicated-pulse-turned-dual-tone-multiple-frequency-DTMF-module-ZZ-9-enhanced/2030415480.html]they can be had for not too much.[/url]

I've learnt more than I want regarding IPC standards, using KiCad and talking to the guys working on the project on IRC. I did not know that the pin 1 indicator dot on PCB silkscreen on SMD packages isn't some sort of standard.

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9621.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9623.jpg[/IMG] I feel like I shouldn't be doing this while drun- [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9627.jpg[/IMG] [b]SON OF A BITCH![/b] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9628.jpg[/IMG] There, one fucking end finished. Now for the other.... [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9629.jpg[/IMG] [editline]Roses are red, violets are blue, I want to fuck you with a rake.[/editline] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9632.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9634.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9643.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9644.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9646.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9652.jpg[/IMG] Now you can see why I've been procrastinating on this for four months. :v:

not really electrical for now, more programming. Im working on a Smart Controller for my Room. i planned following features: -Temperature in and outside -Humidity in and outside -Mq7 and MQ 2 sensors inside (combustable gasses, Carbon monoxide etc. not needed but for 1$, why not) -434mhz transmitter for wireless wall plugs for stuff like subwoofer, workbench etc. -sepperate 434 receiver with a Servo controlling a dimmer for: ceiling fan and lamp. -brightness sensor outside, because my room is facing south and i can lower my jalousie then. -GP2Y1010AU0F air particle counter / dust sensor for monitoring air quality. I ordered the hardware, and im now trying which method i use. Im using an Arduino as I/O port. for processing of all that stuff im using an other device. [B]first method[/B] is using a Windows 7 tablet (because linux and me is like fire and water, and i got one cheaper than any compareable android tab) with a panel written in c# everyhing controlled via serial. thats what i got for now, just for trying how it feels and how much work it will take: [url=http://www.directupload.net/file/d/4044/h6i74ffy_jpg.htm][img]http://fs1.directupload.net/images/150710/temp/h6i74ffy.jpg[/img][/url] [url=http://www.directupload.net/file/d/4044/6u7cv4zq_png.htm][img]http://fs2.directupload.net/images/150710/temp/6u7cv4zq.png[/img][/url] [B]method 2 [/B]is using a local web server (probably my tv receiver running linux.....), which receives and send data to / from arduino and displays it as a local website. accessible trough all devices. usefull with more than 1 tablet. [B]method 3 [/B]is similiar to method one, but im broadcasting all that stuff in my network, im just not using a website. i really like the c# thing.. [B] method 4 [/B]is sending all that stuff to an "public" password protected website, so i can access it from everywhere, and i can use PHP for some fancy stuff like: [IMG]http://peripheral.lima-city.de/gauge.php[/IMG] (sets needle to a random pos, everytime i reload it) or im going to learn javascript/html5 for more fancy displaying methods of Temperature and Humidty

Hey guys, I plan on placing on an order at DX soon so I can stock up some common parts, what would you guys recommend getting?

Does DX even stock any real parts? All I saw was some modules. Pretty limited selection.

Yeah, if I was ordering components DX would be the last place I'd look.

ebay is generally cheaper than DX at most things, and usually quicker. As for what to get you want at the bare minimum: A set of resistors covering the complete E12 series. A set of electrolytic caps and preferably ceramic or film for the lower values. Transistors, bipolar NPN and PNP, N channel MOSFETs and some power transistors. Diodes, 1N4007 rectifier and 1N4148 signal diode. An assortment of LEDs, buttons and switches. Breadboard and a suitable wire such as 23 swg solid core or buy a jumper kit. Useful ICs such as the 555 timer, some op-amps and maybe some 7400 or 4000 series logic. Couple of LM317T voltage regulators.

LM324 is a decent jelly bean quad op amp - 4 op amps in one package, what more could you ask for?

[QUOTE=pentium;48155704] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9652.jpg[/IMG] Now you can see why I've been procrastinating on this for four months. :v:[/QUOTE] How the fuck you know which wires goes to which pin? As I see there are wires of same color three times multiple times each color

You could just use the more modern multimeter contact indicators that beep when you touch wires.

Oh correct, that is yes. Sorry for ignorance

[QUOTE=pentium;48155704] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9623.jpg[/IMG] Now you can see why I've been procrastinating on this for four months. :v:[/QUOTE] Damn, you always take really beautiful photos.

[QUOTE=cartman300;48177102]You could just use the more modern multimeter contact indicators that beep when you touch wires.[/QUOTE] I think there's also the whole "twisted pair" taking effect as well, because while there's multiple colors of wires, there's unique pairs. So while there may be multiple white wires, one will be wrapped with a black one, another with a blue, one with green, etc.

If I need to clamp a current sensor onto the live main wire coming in to my breaker box, what should I do to not kill myself. There's no real way to turn off the power before it comes to the main breaker so I'll have to work on it while live. The only exposed part is the screw terminal but I'd really rather stay alive.

[QUOTE=papkee;48179891]If I need to clamp a current sensor onto the live main wire coming in to my breaker box, what should I do to not kill myself. There's no real way to turn off the power before it comes to the main breaker so I'll have to work on it while live. The only exposed part is the screw terminal but I'd really rather stay alive.[/QUOTE] If you're not qualified to do it and are unsure how to safely proceed, then I'd suggest not doing it, there's no sense risking your bacon if it makes you that nervous.

[QUOTE=Zero-Point;48181549]If you're not qualified to do it and are unsure how to safely proceed, then I'd suggest not doing it, there's no sense risking your bacon if it makes you that nervous.[/QUOTE] Well I mean I understand the principles of electricity and if you touch the screw terminals it could do some bad damage. But either way I found that the mains wires enter the house from up top and I should be able to get readings there without entering the panel. I was just kind of looking for tips or advice. I've installed breakers before, just wanted to know if there are special considerations when dealing with the entry point wires.

[QUOTE=Fourier;48176900]How the fuck you know which wires goes to which pin? As I see there are wires of same color three times multiple times each color[/QUOTE] For starters I got lucky and the original engineering drawings for the cable and the entire interface board are available online. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/CR11_intfc_cbl.png[/IMG] Second, the twisted pairs in the cable were identical to what the drawings expected, so it was simply connect wire to pin with no questions. [editline]11th July 2015[/editline] [QUOTE=papkee;48181835]Well I mean I understand the principles of electricity and if you touch the screw terminals it could do some bad damage. But either way I found that the mains wires enter the house from up top and I should be able to get readings there without entering the panel. I was just kind of looking for tips or advice. I've installed breakers before, just wanted to know if there are special considerations when dealing with the entry point wires.[/QUOTE] When I built [url=http://i11.photobucket.com/albums/a166/ballsandy/DPP_0066.jpg]my own monitoring system[/url] I discovered that you could buy current transformers that could be clipped open and then closed again so you could attach it to a line without actually disconnecting the line itself. Mind you they were for temporary uses... [img]http://tichenassociates.com/images/LCTC_img.jpg[/img]

[QUOTE=papkee;48181835]Well I mean I understand the principles of electricity and if you touch the screw terminals it could do some bad damage. But either way I found that the mains wires enter the house from up top and I should be able to get readings there without entering the panel. I was just kind of looking for tips or advice. I've installed breakers before, just wanted to know if there are special considerations when dealing with the entry point wires.[/QUOTE] You could always just wrap a wire around one of the mains wires and use that as your current sensing loop.

[QUOTE=Zero-Point;48185388]You could always just wrap a wire around one of the mains wires and use that as your current sensing loop.[/QUOTE] I've got one of those clamp sensors. I wasn't thinking when I ordered it but it's the 100A range model so the only way I'm going to get any real reading is with the main feed line to the house. Or I could just order the 15A one...

I just finished my first year in Computer Science and I'm interested in electronics and I wanna learn more about computer architecture in a practical way. I read about retro computer kits and I found that interesting and I found this kit for $109 which is a clone/replica of the computer kits in the 80s and this is a description of it: [quote]The micro-KIM is a clone of the KIM-1 created by MOS Technology in 1975 as a development board for the 6502 CPU. The micro-KIM uses many of the same components as the KIM-1 to give it that authentic vintage feel. No custom components are used and the micro-KIM is designed with off the shelf parts.[/quote] Link: [url]http://www.brielcomputers.com/wordpress/?cat=24[/url] What's your opinion on this? Am I just wasting my money. Are there better kits out there?

So my uncle gave me his Bose 3-2-1 system, because it's broken and he doesn't want to send it off to get fixed. So before I basically gut the system, I want to see if I can find out what's wrong. The 3-2-1 system works like this: The subwoofer is where the power adapter and amplifier for the entire system is. There is a 13(?) pin connector with cable that connects the subwoofer to the receiver. This cable is used to carry power from the subwoofer to the receiver, and preamp audio signals from the receiver to the amplifier in the subwoofer. There is another 9(?) pin connector on the subwoofer (with corresponding cable) that connects the 2 satelite speakers to the amplifier in the subwoofer. So all audio passes through the amplifier in the subwoofer. When I went to pick it up, he showed me that when you plug in power to the subwoofer, it does have a very slight vibration to it, meaning the power transformer inside of the unit DOES work. He also said that the receiver DOES come on and function, however, there is no sound. It appears, to me, to be an issue with the amplifier circuit in the subwoofer. I'm going to double check this by sending a pre-amp audio signal directly into the input circuit to see if it plays. I'm not spending the $200 minimum to send it to Bose for repair. I would rather hack it and make a Frankensystem for my computer or TV before I do that. My question for you guys is where would I start to look for the issue? I already know to look for bad solder points, but after that, my knowledge is limited. How do you go about checking for and finding things like bad caps and such?

[QUOTE=Silence I Kill You;48202614]So my uncle gave me his Bose 3-2-1 system, because it's broken and he doesn't want to send it off to get fixed. So before I basically gut the system, I want to see if I can find out what's wrong. The 3-2-1 system works like this: The subwoofer is where the power adapter and amplifier for the entire system is. There is a 13(?) pin connector with cable that connects the subwoofer to the receiver. This cable is used to carry power from the subwoofer to the receiver, and preamp audio signals from the receiver to the amplifier in the subwoofer. There is another 9(?) pin connector on the subwoofer (with corresponding cable) that connects the 2 satelite speakers to the amplifier in the subwoofer. So all audio passes through the amplifier in the subwoofer. When I went to pick it up, he showed me that when you plug in power to the subwoofer, it does have a very slight vibration to it, meaning the power transformer inside of the unit DOES work. He also said that the receiver DOES come on and function, however, there is no sound. It appears, to me, to be an issue with the amplifier circuit in the subwoofer. I'm going to double check this by sending a pre-amp audio signal directly into the input circuit to see if it plays. I'm not spending the $200 minimum to send it to Bose for repair. I would rather hack it and make a Frankensystem for my computer or TV before I do that. My question for you guys is where would I start to look for the issue? I already know to look for bad solder points, but after that, my knowledge is limited. How do you go about checking for and finding things like bad caps and such?[/QUOTE] Just check all the caps, ICs, and other parts for anything wonky or burned before you begin tearing into it. Sometimes it's the simple things that can make the difference between working and broken. [editline]14th July 2015[/editline] Sorry, didn't see the last line of the post. Caps will either be leaked or bulging at the top, you can check all the resistors with a multimeter to make sure they're in spec, and any ICs will look a bit melted if they've suffered any failure.

I've got old laptop LCD screens, they have 30 input pins and 2 power pins. Could they be used in some standalone projects (let's say a microcontroller) as an output?

[QUOTE=cartman300;48212653]I've got old laptop LCD screens, they have 30 input pins and 2 power pins. Could they be used in some standalone projects (let's say a microcontroller) as an output?[/QUOTE] Depends upon how old the LCD screen is, but there's a plethora of tutorials out there for [URL="http://www.instructables.com/id/How-to-Convert-a-Laptop-LCD-into-an-External-Monit/?ALLSTEPS"]repurposing an old laptop LCD as a standalone monitor[/URL] using a separate VGA/HDMI controller board off of ebay. I'd recommend getting that board and then interfacing your microcontroller over VGA.