Electrical Engineering V2

[pentium]

So much shit to clean up and repair.

[media]http://www.youtube.com/watch?v=pUoXqnQD4zM[/media]

[Ddrl46]

Pulled the CRT out of my HP 180C mainframe because of some problems with the high voltage and bad CRT alignment, fuck this thing is beautiful.

[url=http://i.imgur.com/9MPkQhd.jpg][img]http://i.imgur.com/9MPkQhdl.jpg[/img][/url]

[url=http://i.imgur.com/pUCECy3.jpg][img]http://i.imgur.com/pUCECy3l.jpg[/img][/url]

[url=http://i.imgur.com/HDfwdGU.jpg][img]http://i.imgur.com/HDfwdGUl.jpg[/img][/url]

Here is a HP Journal which talks about these mainframes and the CRTs in them (on page 4): [url]http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1966-08.pdf[/url].

[Fourier]

[QUOTE=ddrl46;45581121]Pulled the CRT out of my HP 180C mainframe because of some problems with the high voltage and bad CRT alignment, fuck this thing is beautiful.

[url=http://i.imgur.com/9MPkQhd.jpg][img]http://i.imgur.com/9MPkQhdl.jpg[/img][/url]
[/QUOTE]

It is beautiful.

[pentium]

I managed to run out of GPIB cables. I wasn't aware that even with my stockpile that was possible.
Also, Fluke fucking sucks for having their GPIB connector upside-down.

[r0b0tsquid]

The handy thing about GPIB cables is that they also make a nice impromptu weapon/flail.

[LoneWolf_Recon]

Hot damn, [URL="http://makezine.com/2014/08/07/the-ti-pi-a-raspberry-pi-powered-ti-994a/"]this is fantastic[/URL], I absolutely love retrofitting (I assume this was done on a dead TI-99):

[video=youtube;NU6UKHG0lqk]http://www.youtube.com/watch?v=NU6UKHG0lqk[/video]

[Zero-Point]

Who's got two thumbs and a 9000V neon sign transformer?

Probably a bunch of people, but I now stand amongst them.

[Nutcake]

What do you plan on doing with it?

[TCWilliamson]

[QUOTE=Zero-Point;45626147]Who's got two thumbs and a 9000V neon sign transformer?

Probably a bunch of people, but I now stand amongst them.[/QUOTE]

Cute, pity its only like 20mA likely.

You should try out a Potential Transformer, my one is 10,000v but they are built so well you can put mains into it and get 23,000v out and can have stupidly high current through it.

The only disadvantage is that they need ballasting or they will burn up.

[pentium]

[QUOTE=LoneWolf_Recon;45625226]Hot damn, [URL="http://makezine.com/2014/08/07/the-ti-pi-a-raspberry-pi-powered-ti-994a/"]this is fantastic[/URL], I absolutely love retrofitting (I assume this was done on a dead TI-99):

[video=youtube;NU6UKHG0lqk]http://www.youtube.com/watch?v=NU6UKHG0lqk[/video][/QUOTE]

This looked awesome until the fucking LED's.
What compells people to add such tacky lighting to this shit? Aside from that it's fucking fine.

[LoneWolf_Recon]

[QUOTE=pentium;45634667]This looked awesome until the fucking LED's.
What compells people to add such tacky lighting to this shit? Aside from that it's fucking fine.[/QUOTE]

I thought the SD card reader in the speech synth was a nice touch.

[Zero-Point]

[QUOTE=nuttyboffin;45631919]Cute, pity its only like 20mA likely.

You should try out a Potential Transformer, my one is 10,000v but they are built so well you can put mains into it and get 23,000v out and can have stupidly high current through it.

The only disadvantage is that they need ballasting or they will burn up.[/QUOTE]

This here's a 30mA gen-yoo-ine Franceformer neon sign transformer, but I bow down to your obviously superior dicking about with potentially lethal potentials. Allow me to make a Jacob's Ladder in penance, so that the next time you see it appropriate to wave thine penis about, you'll have a suitable place to do so, Sire. It's only 30 mA, so I'm sure you'll be fine. :^)

[TCWilliamson]

[QUOTE=Zero-Point;45636335]This here's a 30mA gen-yoo-ine Franceformer neon sign transformer, but I bow down to your obviously superior dicking about with potentially lethal potentials. Allow me to make a Jacob's Ladder in penance, so that the next time you see it appropriate to wave thine penis about, you'll have a suitable place to do so, Sire. It's only 30 mA, so I'm sure you'll be fine. :^)[/QUOTE]

Thank you good sir!

Although. I have not got a single NST, i somewhat jumped the levels in high voltage. started with an MOT, then straight to an x-ray transformer and now a potential transformer. While i admit i have far higher voltages and currents then your puny NST, i do have slight envy of you actually having one ^-¬

[Zero-Point]

[QUOTE=nutcake;45630588]What do you plan on doing with it?[/QUOTE]

Not sure at this point. Probably something simple like a Jacob's Ladder at first, possibly a Tesla Coil later on.

[TCWilliamson]

Did a video of my PT.

[media]http://www.youtube.com/watch?v=YgiQCqo1REk&hd=1[/media]

[Chryseus]

So I finally got off my arse and built the filter for my ECG, after a bit of thinking I decided on a 8th order bessel filter using the sallen-key topology with the cutoff set at 40Hz, originally I was going to use a chebyshev response but that would have a large phase delay and poor transient response which is no good at all for a time invariant signal.

[t]http://u.cubeupload.com/Chryseus/eSyZJE.jpg[/t]
[t]http://u.cubeupload.com/Chryseus/f13tEF.png[/t]

I still need to add a decent 50Hz notch filter with adjustable Q and experiment with RLD (Right Leg Drive) feedback, hopefully that should give me a fairly good signal.

[Leestons]

I want to build something but don't know what. I was thinking of something like a headphone amplifier but I'd need to get two sockets for the input and output and the circuit is mono so it's just a pain in the arse. Any suggestions for a newbie?

[Chryseus]

[QUOTE=Leestons;45645205]I want to build something but don't know what. I was thinking of something like a headphone amplifier but I'd need to get two sockets for the input and output and the circuit is mono so it's just a pain in the arse. Any suggestions for a newbie?[/QUOTE]

Two sockets ? you can get stereo 3.5mm sockets and plugs.
Also use two mono circuits for stereo, things like volume control can be done with a dual pot.

[r0b0tsquid]

10kHz sine wave from an FPGA
[img]http://i.imgur.com/24kMzGY.jpg[/img]
[img]http://i.imgur.com/rBXcWhV.jpg[/img]

[Leestons]

[QUOTE=Chryseus;45647484]Two sockets ? you can get stereo 3.5mm sockets and plugs.
Also use two mono circuits for stereo, things like volume control can be done with a dual pot.[/QUOTE]

Sorry I should have worded it better. By two sockets I meant one for the input and one for the output. I know I could use two circuits but it all sounds cumbersome. I'll think about it.

[alealienn]

What program did you guys use to project PCB boards? I'm using Proteus ISIS right now and MatLab for do some equations....

[Leestons]

diptrace

[Ddrl46]

I use EAGLE, not the best thing out there but it works for what I do.

[TCWilliamson]

Eagle Masterrace, really quite good software, recently used it for a professional job.

[alealienn]

Thank you guys, I'll check EAGLE

[RoflKawpter]

I'm making some kind of solar light for a metal post out front of our house, so I went to dollar store and grabbed 6 cheapo solar lights, ripped out the guts, and hooked up 2 sets of 3 solar panels in series in parallel to the cheapo Chinese board with a ghetto charge controller (oh if the voltage in the panel drops below a certain point then stop charging and light the led) and output it to the 6 batteries I harvested. Seems to work quite well! not that bright though. I assume it's because the batteries are in series and not parallel which causes lower amperage to the leds? (imma novice, so be easy on me!)

[Leestons]

[QUOTE=RoflKawpter;45668021]I'm making some kind of solar light for a metal post out front of our house, so I went to dollar store and grabbed 6 cheapo solar lights, ripped out the guts, and hooked up 2 sets of 3 solar panels in series in parallel to the cheapo Chinese board with a ghetto charge controller (oh if the voltage in the panel drops below a certain point then stop charging and light the led) and output it to the 6 batteries I harvested. Seems to work quite well! not that bright though. I assume it's because the batteries are in series and not parallel which causes lower amperage to the leds? (imma novice, so be easy on me!)[/QUOTE]

Batteries in series
Va + Vb (Double the voltage, same current)

Batteries in parallel
Ca + Cb (Double the current, same voltage)

[RoflKawpter]

Just out of curosity (because why not), Is it possible to somehow reuse a wireless doorbell system so that you can set up some sort of one way transmitter/receiver with two microcontrollers? Maybe for data ? (although I can assume the bandwidth would be HORRENDOUSLY low) Like for example:

Base station transmits (using the door bell button) a series of button presses that the receiving station gets and translates them into commands? I assume you would have to somehow set up failsafes if instructions don't get interpreted correctly or sent wrong or stuff like that.

[LoneWolf_Recon]

[QUOTE=RoflKawpter;45671870]Just out of curosity (because why not), Is it possible to somehow reuse a wireless doorbell system so that you can set up some sort of one way transmitter/receiver with two microcontrollers? Maybe for data ? (although I can assume the bandwidth would be HORRENDOUSLY low) Like for example:

Base station transmits (using the door bell button) a series of button presses that the receiving station gets and translates them into commands? I assume you would have to somehow set up failsafes if instructions don't get interpreted correctly or sent wrong or stuff like that.[/QUOTE]

I don't see why not, could just simply replace the doorbell button and chime with a transistor and photocoupler respectively.

[RoflKawpter]

Cool!

Another question (sorry, I'm on like a binge of this stuff right now, I'd like to run with it as far as I can before I burn out and have to wait till im interested again :P )

These 7.5 solar panels I have. They have either a cigarette lighter output or a USB Output. Would it be better to charge a portable battery pack if I took the USB outputs on the panels, wired them in parallel for more amperage, and connected them to the USB Input on the charger versus wiring the cigarette lighter outputs on the solar panels in parallel to a voltage converter (to 5v) and output that to the charging battery? I assume there would be oscillations from the cigarette lighter, whereas I assume the USB outputs on the panel are regulated already (as best as you can with solar panels, I assume)

Thanks for all the help guys! I'm picking this up as a hobby instead of a career (I tried engineering in university, but it's just too much for me!) so I'd like all the help I can get :)