Electrical Engineering V3 - Developers

[img]http://i11.photobucket.com/albums/a166/ballsandy/Philips%20EL-3400/IMG_2958.jpg[/img] Only the dutch would design such an absurd switching mechanism. ffs A motor on the backside rotates a set of cams. Each metal rod is pushed or pulled by a lobe into a position and bridges a set of electrical contacts. A metal disc above the cams and more contacts are used to position everything. Instead of, you know, using a fucking stacked wafer switch.

[QUOTE=Van-man;49900556]I assume you both want to charge the "host" device, while also supplying external power to the "slave" device(s). Normal USB OTG cables have ID/sense pin shorted to ground, but seems like most phones support charging if instead of directly shorting that pin to ground, it's connected via a 100K ohm resistor. So you'd probably want a cable wired up like this: [t]http://s22.postimg.org/qqt1ycu75/Y_OTG_CABLE_png_attachauth_ANo_Y7co_Uw_KLN_PZDx_Eg_Qn.png[/t] There probably are a few on ebay wired up just like that, but as usual with anything ebay, buy from a reputable seller with clear & concise description of product.[/QUOTE] Thanks! I just ordered some USB OTG Y cables and I hope it works.

[IMG]http://i.imgur.com/XOG4AhW.png[/IMG] :what: (Compare the dimensions of the pads to the pitch) I had to switch XO manufacturer because I can't understand their fucking datasheets, the whole thing is like that.

[QUOTE=Tobba;49923961][IMG]http://i.imgur.com/XOG4AhW.png[/IMG] :what: (Compare the dimensions of the pads to the pitch) I had to switch XO manufacturer because I can't understand their fucking datasheets, the whole thing is like that.[/QUOTE] What? Seems reasonable to me. The centers of the pads are 2.5mm apart, while the pads themself have a width of 1.2mm. So that leaves you with 1.3mm of space between the pads, which is a lot.

[QUOTE=DrDevil;49924763]What? Seems reasonable to me. The centers of the pads are 2.5mm apart, while the pads themself have a width of 1.2mm. So that leaves you with 1.3mm of space between the pads, which is a lot.[/QUOTE] The proportions are absolutely fucked, the dimensions they specify are probably correct, but I don't trust it one bit. The land pattern they specify looked pretty iffy when drawn with correct proportions as well. Faster and easier to just switch manufacturer instead of risking having to order a new batch of boards, botching the oscillator means I might not be able to test any of the more problematic high-speed interconnects (100 MHz SDRAM) [editline]13th March 2016[/editline] If you produce a generic component and can't draw good datasheets, I ain't dealing with your shit unless every cent matters.

[IMG]http://i.imgur.com/rF59XAb.jpg[/IMG] :v: [editline]13th March 2016[/editline] Gets a point for the safety squints though.

I have seen this same image with different watermarks every day for the past month.

Sorry :(

So.. emulating mouse through Arduino on Android is nearly impossible, because Android has mouse acceleration... and even if I emulate velocity correctly, somehow things still get fucked up. (I don't have absolute positioning)

[img]http://i11.photobucket.com/albums/a166/ballsandy/Philips%20EL-3400/IMG_3030.jpg[/img] [b]FUCK ME.[/b] This drum is going to be such a massive fucking pain in the ass to resurface.

[QUOTE=Tobba;49926025]The proportions are absolutely fucked, the dimensions they specify are probably correct, but I don't trust it one bit. The land pattern they specify looked pretty iffy when drawn with correct proportions as well. Faster and easier to just switch manufacturer instead of risking having to order a new batch of boards, botching the oscillator means I might not be able to test any of the more problematic high-speed interconnects (100 MHz SDRAM) [editline]13th March 2016[/editline] If you produce a generic component and can't draw good datasheets, I ain't dealing with your shit unless every cent matters.[/QUOTE] Never trust the land pattern to be correct because often they are not. Take a look at this horrible one from muRata: [img]http://i.imgur.com/4a0aZpK.png[/img]

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Philips%20EL-3400/IMG_3055.jpg[/IMG] Part of me died when I did this. A 50 year old $30000 piece of video equipment with no hopes to replace and I was going at it with a grinding stone to remove the corrosion. Now all that is left is to polish the tape back back to something useable and measure the head gap as it's obviously gonna change.

[QUOTE=Leestons;49926914][IMG]http://i.imgur.com/rF59XAb.jpg[/IMG] :v: [editline]13th March 2016[/editline] Gets a point for the safety squints though.[/QUOTE] I accidentally grabbed a soldering iron like that once, I sure as hell wasn't as calm as the lady on the picture

Question on logic gates: So I looked up the sheet for an AND gate and saw this: [img]http://i.imgur.com/H5r83c1.png[/img] Am I to understand that the input and output work just as it would in a diagram, but the vcc has to be connected to just the positive terminal on my prototyping board, and the ground likewise to the negative? it's that simple?

The wiring for pins 3 and 5 are not drawn in for the sake of simplicity but yes, if you don't apply some form of power the logic will not function. [editline]Mad Chatter[/editline] Does anyone have a cheap source for the carbon microphones found in telephone handsets? I have on here in a shitty retro iphone handset but I don't want to be left with a handset you can't speak into and quickly looking on ebay all I'm getting are e-cig parts and old expensive soviet surplus.

[QUOTE=scratch (nl);49932741]I accidentally grabbed a soldering iron like that once, I sure as hell wasn't as calm as the lady on the picture[/QUOTE] My soldering iron and stand fell off my desk once. It sure as hell didn't touch the ground, by damn.

My soldering iron once fell in the trash bin which I had to quickly put out :v:

[QUOTE=Zero-Point;49934785]My soldering iron and stand fell off my desk once. It sure as hell didn't touch the ground, by damn.[/QUOTE] I once tried to make a ghetto soldering iron out of pencil graphite and 5v USB cord. Burnt my fingers holding it.

Dave Cook of RobotRoom.com hasn't been putting out too much lately, but his successor to his original LED tester is pretty handy: [video=youtube;O7f8aU2HzOM]http://www.youtube.com/watch?v=O7f8aU2HzOM[/video]

I needed to cool down some resistors I was using as a test load today. Ended up with a custom watercooling solution. [t]https://i.imgur.com/Ml4A0Wk.jpg[/t] I call it the "soda bottle with some water in it, sitting on top of the resistors" setup. Ended up working pretty well, resistors didn't go above 61C under load. Which was probably actually hotter than that, since I just had the K-type thermocouple sitting under the resistors, but it was pretty OK since the bottle had weight to it, so it pressed the resistor against the thermocouple.

I'm interested in digital logic. I'm looking at logic gates on aliexpress but I'm still not entirely sure about the basics of EE. If I'm looking to power a circuit qith a simple 5v 0.5A USB cord, what types of specs would I be looking for in logic circuits?

[QUOTE=proboardslol;49945742]I'm interested in digital logic. I'm looking at logic gates on aliexpress but I'm still not entirely sure about the basics of EE. If I'm looking to power a circuit qith a simple 5v 0.5A USB cord, what types of specs would I be looking for in logic circuits?[/QUOTE] Look at using CMOS logic to start out with, super simple and works fine on 5V. Such prefixes would be 74HC or 74AC. Honestly I'd recommend an FPGA system over discrete logic if you're unsure about the electrical side of it. You'll get almost 1-to-1 experience working with an FPGA system as opposed to discrete logic chips without worrying about breadboard space/wire. [URL="http://store.digilentinc.com/basys-2-spartan-3e-fpga-trainer-board-limited-time-see-basys-3/"]Digilent's BASYS2 Board[/URL] runs for $150 and runs off of USB.

hope you like learning verilog

[QUOTE=elitehakor;49945994]hope you like learning verilog[/QUOTE] Lets not forget VHDL which isn't too bad IMO, and most development environments support switching back and forth between Schematic & VHDL/Verilog development.

you can also get way cheaper boards. since you're gonna use it for learning you can def compromise [url]http://numato.com/elbert-v2-spartan-3a-fpga-development-board/[/url] is what i'd suggest [editline]16th March 2016[/editline] [QUOTE=LoneWolf_Recon;49946033]Lets not forget VHDL which isn't too bad IMO, and most development environments support switching back and forth between Schematic & VHDL/Verilog development.[/QUOTE] never used vhdl. how is it compared to verilog?

My buck converter ended up being a really shitty linear regulator. I need to fix that this weekend.

When it's past 10pm on a Saturday, and you're doing something for yourself. [t]https://i.imgur.com/NErfof3.png[/t]

I always spec supercaps for my decoupling. [editline]19th March 2016[/editline] 5 farad input and output filter caps. [editline]19th March 2016[/editline] Keeps the noise down

[QUOTE=LoneWolf_Recon;49945858]Look at using CMOS logic to start out with, super simple and works fine on 5V. Such prefixes would be 74HC or 74AC. Honestly I'd recommend an FPGA system over discrete logic if you're unsure about the electrical side of it. You'll get almost 1-to-1 experience working with an FPGA system as opposed to discrete logic chips without worrying about breadboard space/wire. [URL="http://store.digilentinc.com/basys-2-spartan-3e-fpga-trainer-board-limited-time-see-basys-3/"]Digilent's BASYS2 Board[/URL] runs for $150 and runs off of USB.[/QUOTE] Maybe not great for beginners, there are few specific resources, but [URL="http://www.clifford.at/icestorm/"]Project Icestorm[/URL] is really cool, it's a fully open source FPGA toolchain.

What the fuck happened to this power supply. Four 35v 22uf capacitors. Two clipped, one blown up and clipped and the fourth totally missing Two 1N4007's that were hastily tacked on to the clipped leads of the old one. One is a dead short and the other reads infinite. A -5v regulator installed on the underside of the board, shorting base to +12. Two 2w resistors so cooked the color bands are unreadable. Amazing.