Electrical Engineering V3 - Developers

[QUOTE=No_Excuses;50809766][url]https://www.reddit.com/r/arduino/comments/4lsoyn/my_first_attempt_at_soldering_can_someone_tell_me/[/url][/QUOTE] Two months ago , that's why I couldn't find it on /new. Thanks!

[QUOTE=No_Excuses;50809540]Just browsing the arduino subforum of reddit and came across this piece of work: [thumb]http://i.imgur.com/iu2bRVp.jpg[/thumb][/QUOTE] On the bright side free solder! [sp]Who doesn't recycle solder, ya plebs[/sp]

[QUOTE=No_Excuses;50809540]Just browsing the arduino subforum of reddit and came across this piece of work: [thumb]http://i.imgur.com/iu2bRVp.jpg[/thumb][/QUOTE] :sick:

[QUOTE=LoneWolf_Recon;50810509]On the bright side free solder! [sp]Who doesn't recycle solder, ya plebs[/sp][/QUOTE] I had to reuse solder in my high school engineering (metal filing is a more apt name) class because there was fuck all and people kept making love hearts instead of using it for the thing we were making. Went about as well as you can imagine trying to solder onto old nails with no flux. Then someone hooked a couple of batteries up the wrong way and blew all the LEDs on mine when I wasn't looking.

So it looks like arse right now, but Frankendoodle as I rather like to call this thing, is live. [VID]https://f.lewd.se/a7PSnB_VID_20160801_213621.mp4[/VID]

[QUOTE=Merijnwitje;50812200]So it looks like arse right now, but Frankendoodle as I rather like to call this thing, is live. [VID]https://f.lewd.se/a7PSnB_VID_20160801_213621.mp4[/VID][/QUOTE] That thing looks like it could cut a finger off easily :v:

-snip because now I'm paranoid-

[video=youtube;07EctdVlX0w]https://www.youtube.com/watch?v=07EctdVlX0w[/video] 2nd year student here strange question: I want to implement the mechanism in the above product (not the midi part) on a smaller scale -- would an actuator be the way to go here? are there other components that make percussive strikes like this? ideally i want to be able to control when it hits and how hard it hits a thing.

[QUOTE=AGMadsAG;50807109]It's not really changing the amount of power going into the motor, it is changing how often. Or how much power over time. Look up PWM (Pulse Width Modulation).[/QUOTE] [QUOTE=gjsdeath;50807139]In that video I was using an N channel MOSFET to drive the motor. Similar to this diagram I just Googled: [t]http://bildr.org/blog/wp-content/uploads/2012/03/rfp30n06le-arduino-motor.png[/t][/QUOTE] Thank you guys, I now made my own little motor controller using the Arduino! Proud of myself :smile:

I'm getting my ESD certification/training today, up to the JPL standard so I can work on the hardware for our military and NASA contracts. Jokes on all of them, I'm terrible at soldering but at least I get to play with some really nice scopes and function generators.

[QUOTE=paindoc;50820359]-snip-[/QUOTE] I would be reeeallly careful about what you post about your company. The government doesn't fuck around with ITAR or things relating to the military.

[QUOTE=Dolton;50822512]I would be reeeallly careful about what you post about your company. The government doesn't fuck around with ITAR or things relating to the military.[/QUOTE] I mean, I had only used publicly available links and information so far. Nothing unlisted, private, classified, or restricted. Most of our contracting work is through NASA so our data ends up in the public domain. Currently WIP efforts are supposed to be hush-hush in terms of their details and findings, though. This primarily means performance benchmarks and the like. So, if I understand it, saying vaguely how we do something would be fine so long as I don't say "it improved our times x-fold" or "we now no issue with the <previous issue/mechanism>" etc. Since I am paranoid now, mind snipping my post from your post?

That's a cool as shit job honestly, good luck with it all. I honestly wish CubeSats would become a bit more available beyond requiring some sort of grant from a university. Speaking of which, [URL="http://www.mouser.com/empowering-innovation/iss-project/?cm_sp=homepage-_-homeintro-_-eit-iss"]Mouser is currently hosting an ISS Engineering Challenge for designing a 3D printed/electronic gadget for astronauts to use on the ISS.[/URL]

[QUOTE=LoneWolf_Recon;50822890]That's a cool as shit job honestly, good luck with it all. I honestly wish CubeSats would become a bit more available beyond requiring some sort of grant from a university. Speaking of which, [URL="http://www.mouser.com/empowering-innovation/iss-project/?cm_sp=homepage-_-homeintro-_-eit-iss"]Mouser is currently hosting an ISS Engineering Challenge for designing a 3D printed/electronic gadget for astronauts to use on the ISS.[/URL][/QUOTE] We really just need launch costs to get down even further, at this point. There will still be the issues with component cost, however, as space-grade electronics are rarely cheap. also, that contest may be finishing/printing the entries around the time our stuff is headed up there, so I'll have to keep an eye on it.

[QUOTE=paindoc;50822971]We really just need launch costs to get down even further, at this point. There will still be the issues with component cost, however, as space-grade electronics are rarely cheap. also, that contest may be finishing/printing the entries around the time our stuff is headed up there, so I'll have to keep an eye on it.[/QUOTE] Yeah rad-hard stuff is a pain in the butt, but its slowly starting to break into the hobbyist market. A couple months ago, Atmel announced their [URL="http://www.atmel.com/devices/ATmegaS128.aspx"]AtmegaS128[/URL], a rad-tolerant AVR that's probably several orders of magnitude cheaper than the typical rad-hard faire. I emailed their sales dept to see if individuals could buy any, but still no response. The contest is pretty limiting but for good reason [URL="http://www.mouser.com/pdfDocs/ISS_Guidelines.pdf"](i.e. No RF, no WiFi, Switching Regs are discouraged, no HV or high current, and only to run off of a couple of AAs or a coin cell)[/URL]. Honestly, it seems like an awesome exercise in strict design without delving into the rabbit-hole of standards, I'd imagine.

Not much cause for wifi standards in space.

There's worry about any sort of radiating field in general, the ISS has had an incredibly successful operations history due to ridiculously tough standards in no small part I imagine. [QUOTE=LoneWolf_Recon;50823011]Yeah rad-hard stuff is a pain in the butt, but its slowly starting to break into the hobbyist market. A couple months ago, Atmel announced their [URL="http://www.atmel.com/devices/ATmegaS128.aspx"]AtmegaS128[/URL], a rad-tolerant AVR that's probably several orders of magnitude cheaper than the typical rad-hard faire. I emailed their sales dept to see if individuals could buy any, but still no response. The contest is pretty limiting but for good reason [URL="http://www.mouser.com/pdfDocs/ISS_Guidelines.pdf"](i.e. No RF, no WiFi, Switching Regs are discouraged, no HV or high current, and only to run off of a couple of AAs or a coin cell)[/URL]. Honestly, it seems like an awesome exercise in strict design without delving into the rabbit-hole of standards, I'd imagine.[/QUOTE] A lot of the Cortex M4F variants get used in space hardware - its what we're using for our university cubesat effort. They have decent resistance to SEUs and good-enough total dosage resistance/tolerance. The main thing I studied was memory hardware and space weather (risk analysis and mitigation plans, mainly). If you're interested, I can PM you either document it but I'd rather not post it since it's got my personal info all over.

Does anyone have a datasheet for a mikrosemi CMGEGF400U120D4AG? The only thing I know is that it's 1200v 400a. Googling it on yields a few ebay and Chinese seller results. Can't find anything on mikrosemi's website either.

Hey guys. Can we discuss multimeters again? I bought a new one after my last one failed. It was spur of the moment because it was on sale one day. It's not very accurate and completely stopped reading voltage for some reason. Resistance is way off, too. I didn't even get to use For my purposes I need an ammeter with a range of 1A and a voltmeter that can read up to 18v. I kind of just want to go with an analog multimeter but I have never used one before and all of the meters I find only go up to 250mA.

fluke ftw

The fluke 15B+ is probably the best budget meter right now. It's $80 or so from several places online. I've got one and it has worked great for everything I've needed so far.

Okay I just got out of the shower and I just had an awesome idea. Could one of the RF guys chime in with opinions? Ddrl46? So giant brick phones, portables and car phones that run on AMPS are pretty much useless now even though they look cool as shit. I know there's been one article on how to make an AMPS repeater that fits in a briefcase for a while now but it's constantly taken down because it's horribly illegal to run a transmitter like that. What if we eliminated the need to retransmit wirelessly over AMPS? WE already have a good idea on how the AMPS communication protocol works. What if we removed the antenna off the phone and using a piece of coax linked it to the repeater which at its basic form is an SDR, a microcontroller and a GSM cell module? You wouldn't need any sort of high transmit power on the SDR to connect to the phone and vice-versa because they are directly linked. You could then in theory emulate an AMPS repeater and you won't run into issues with your local regulatory officials, yes?

You could replace the internal master oscillator with something that moves the operating frequency into the 900MHz ISM band, and hope that the low pass filters on the final RF amplifier doesn't attenuate the signal too much. Then you could operate your own AMPS repeater!

[QUOTE=pentium;50887749]Okay I just got out of the shower and I just had an awesome idea. Could one of the RF guys chime in with opinions? Ddrl46? So giant brick phones, portables and car phones that run on AMPS are pretty much useless now even though they look cool as shit. I know there's been one article on how to make an AMPS repeater that fits in a briefcase for a while now but it's constantly taken down because it's horribly illegal to run a transmitter like that. What if we eliminated the need to retransmit wirelessly over AMPS? WE already have a good idea on how the AMPS communication protocol works. What if we removed the antenna off the phone and using a piece of coax linked it to the repeater which at its basic form is an SDR, a microcontroller and a GSM cell module? You wouldn't need any sort of high transmit power on the SDR to connect to the phone and vice-versa because they are directly linked. You could then in theory emulate an AMPS repeater and you won't run into issues with your local regulatory officials, yes?[/QUOTE] Sounds like a recipe for destroying your receiving end. You'd definitely have to lower the gain of the TX-amp.

If you don't want to modify the output stage though, you could use a [url=https://en.wikipedia.org/wiki/Power_dividers_and_directional_couplers]directional coupler[/url]. If you take this setup for example: [img]https://upload.wikimedia.org/wikipedia/en/thumb/8/84/Coupled_line_directional_coupler.svg/220px-Coupled_line_directional_coupler.svg.png[/img] You'd 50-ohm-terminate ports 2 and 3, and respectively connect the phone and SDR to ports 1 and 4. That way you can blast out at normals powers and don't have to be afraid to overload or even blow out your receiver stages.

[QUOTE=DrDevil;50890982]If you don't want to modify the output stage though, you could use a [url=https://en.wikipedia.org/wiki/Power_dividers_and_directional_couplers]directional coupler[/url]. If you take this setup for example: [img]https://upload.wikimedia.org/wikipedia/en/thumb/8/84/Coupled_line_directional_coupler.svg/220px-Coupled_line_directional_coupler.svg.png[/img] You'd 50-ohm-terminate ports 2 and 3, and respectively connect the phone and SDR to ports 1 and 4. That way you can blast out at normals powers and don't have to be afraid to overload or even blow out your receiver stages.[/QUOTE] Since MIPS is talking about old phones, doesn't that mean he'd need a bi-directional coupling instead?

[QUOTE=Van-man;50891086]Since MIPS is talking about old phones, doesn't that mean he'd need a bi-directional coupling instead?[/QUOTE] Unless I'm overlooking something, this should be bidirectional.

[QUOTE=DrDevil;50890982]If you don't want to modify the output stage though, you could use a [URL="https://en.wikipedia.org/wiki/Power_dividers_and_directional_couplers"]directional coupler[/URL]. If you take this setup for example: [IMG]https://upload.wikimedia.org/wikipedia/en/thumb/8/84/Coupled_line_directional_coupler.svg/220px-Coupled_line_directional_coupler.svg.png[/IMG] You'd 50-ohm-terminate ports 2 and 3, and respectively connect the phone and SDR to ports 1 and 4. That way you can blast out at normals powers and don't have to be afraid to overload or even blow out your receiver stages.[/QUOTE] That's some witchcraft! [sp]And I absolutely love it.[/sp] Man, my knowledge of electronics becomes wonky past VHF, anything beyond is magic. :magic101:

Recently I finished building a nixie tube clock. I didn't make any of it myself, I bought a kit for it. But it was good fun to put it all together and solder everything. A couple of days ago I also built a cheap oscilloscope. Probably going to make a lot of you guys cringe but for basic use like measuring duty cycles and such, it's okay. I'm not so hardcore into this at the moment that I need a $400 scope. My next project is going to be building a CNC machine and hopefully a 3D printer out of an inkjet printer and scanner husk, and some steppers out of floppy drives for Z-axis control. Then hopefully have it sturdy enough for milling so I can have everything I need to mill my own PCBs (I hate perfboards). [img_thumb]http://i.imgur.com/C5RridC.jpg[/img_thumb] [img_thumb]http://i.imgur.com/xjGGARV.jpg[/img_thumb] [vid]https://my.mixtape.moe/miocvq.mp4[/vid]

[QUOTE=LoneWolf_Recon;50893010]That's some witchcraft! [sp]And I absolutely love it.[/sp] Man, my knowledge of electronics becomes wonky past VHF, anything beyond is magic. :magic101:[/QUOTE] Most of that witchcraft is incredibly simple, really.