Electrical Engineering V3 - Developers

[t]http://i.imgur.com/VWLFzJO.jpg[/t] My new clock has a 10MHz reference frequency input.

I've got to get all the clocks at our shack referenced. We've got a really nice and probably very expensive GPS reference rack mounted that's always on and never has anything connected to it.

Speaking of GPS units I kind of one a Trimble Placer 450/455, but I can buy much better chinese units these days.

Every bit of test gear we have is now calibrated to +/- 0.5 Hz :v: That was fun. Also I should post our new wall of gear. It's not on the level some of you guys are at but it's a lot of HP and a lot of fun.

Trying to identify the frequency of this RFID Card, not sure if anyone has any experience with them but it's either 13.56MHz or 125kHz. Don't have a picture but it's credit card sized and on the inside it's got a copper coil around the edge of the card on the inside (about 1.5mm-2mm thick) with a chip at the top right (about 8mm x 5mm). The card is used with two types of reader, one you have to practically place it on top of to work properly (used inside a building) and a stronger one which works through wallets etc (used externally).

[media]https://www.youtube.com/watch?v=GGbS8ahchlo[/media] Here is my boost converter for geiger counters and other loads less than a few mA, it can be adjusted from the supply voltage to about a maximum of 700V, switching at 10kHz 80% duty. It isn't the most elegant design but it works, you can see the switching of the comparator superimposed on the drive signal on the scope, input current is about 120mA at 6V so it's only 60% efficient at a 1mA load, increasing the duty closer to 97% would help but that isn't too easy to do. Actually I might be able to manage 90% or more, back to testing.

Silly me for assuming these [url=http://www.ebay.ca/itm/1PCS-NEW-SI4432-470MHz-470M-433mhz-1000m-Wireless-Communication-Module-/360958915169?hash=item540ad3f261:g:E0wAAOSwAL9UhHtp]Si4432 transceiver boards[/url] would be 0.1" pinpitch. [t]http://i.imgur.com/ZJ29UTE.jpg[/t] Bodge time!

Picture of the new bench as promised. [t]http://i.imgur.com/TLaJQvC.jpg[/t] Also I now know how to use all of it!

I've built a jacob's ladder when I noticed that it started oscillating [img]https://my.mixtape.moe/gdovqb.gif[/img] Video of our setup: [media]https://www.youtube.com/watch?v=xZS3KkIvqaU[/media] The oscillations come from the electric field across the wires. It makes the wires attract each other, until the spark flies over and the gap starts to conduct. At that moment, the potential of both wires is more or less equal and thus the attractive force vanishes (there should be a tiny bit of magnetic attraction coming into play, but it's much smaller than the force form the electric field). When the wires spring back, the spark vanishes, and they start to attract each other again. Do you guys think this theory is correct? It seems very plausible to me, especially seeing how the wires started moving way before the spark formed. (In fact, they wouldn't move at all if the spark would form while the wires were stationary) [editline]2nd March 2016[/editline] Got another one: [url]https://my.mixtape.moe/ckrvsj.gif[/url] (3.5MB)

Those Chinese temperature controllers are actually kinda nice. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2718.jpg[/IMG] I bought one so I could convert a food dehydrator into a controlled [url=https://en.wikipedia.org/wiki/Sticky-shed_syndrome#Solutions]tape baking machine.[/url] It's not yet properly mounted but the idea is I can use the internal 10A relay to switch the heating element on and off while also keeping the temperature within a programmable limit. The kit cost $10, the instructions had absolutely no chinese on them and it had fucking readable diagrams. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2709.jpg[/IMG]

i got myself one of these 15$ PID Temperature controllers with Solidstate relay. pretty nice for the price. im using it for melting chocolate

Tadah. [t]https://i.imgur.com/a556S1z.jpg[/t] Smallest traces are 0.25mm, so they're fairly massive, but it's good enough for home usage. Letting the board float in etchant so the other side is completely clear, after that I need to drill the holes, which is going to be really annoying.

I thought I'd save a pullup resistor on the button, and I used the internal pullup on the Tiny85. Turns out, the pullup is weak enough that putting my finger [I]near[/I] the button, is enough to pull it to ground.

Done. Now I can start cookin'. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2721.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2724.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2733.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_2755.jpg[/IMG]

If you needed to heat up some tapes, you could have just asked me to send you my latest mix tape. [editline]3rd March 2016[/editline] nvm those things aren't fireproof

Heads up PNW'ers. Sphere's having their annual free day [url=http://www.sphere.bc.ca/test/stuffday.html]next month[/url]. I've gone two years in a row now and each time even if I have no reason to go I've come back with way more than I'll ever need. I strongly recommend you go if you can make it somehow.

[QUOTE=pentium;49857778]Heads up PNW'ers. Sphere's having their annual free day [url=http://www.sphere.bc.ca/test/stuffday.html]next month[/url]. I've gone two years in a row now and each time even if I have no reason to go I've come back with way more than I'll ever need. I strongly recommend you go if you can make it somehow.[/QUOTE] I wish I had a car, or lived closer so I could get in on that. :c

[img]http://i.imgur.com/2z0gT5s.png[/img] [img]http://i.imgur.com/TfvcIB0.png[/img] Just need to wait for some last parts to arrive :dance: I'm doing the PCB myself so we'll see how that goes, I think I've got my technique down now.

0.25mm traces were easy with the method I used for the board I made last. [media]https://imgur.com/a/vmxUj[/media] Toner transfer paper + PCBFX toner foil + sodium persulfate + 100-1000mA [editline]4th March 2016[/editline] Drilling holes is a bitch though.

I suggest you get some vinyl sheet, it does very very good transfers and leaves no paper fibers behind, I've had no issues getting 0.1mm (4 thou) traces with a 1200dpi printer. As for drilling holes a good budget method is those tiny collet chucks on the end of a small dc motor, nothing beats a proper drill press though.

I'm not sure I've ever posted these here before, but I've got more of those if you wanna see them [t]https://my.mixtape.moe/sfpzcx.jpg[/t] Also great artistic arc: [t]https://my.mixtape.moe/ytvfkt.png[/t]

Yes please, more high voltage porn, you slut

[QUOTE=Timezbrick;49859011]Does anyone know here know car electronics well enough to help me? I need to override a safety switch on a Automatic 1973 BMW so I can start it in any gear. I have reasons to believe that the safety switch is busted and I would like to confirm it. ( I would also like to just drive the damn thing again ) These might be useful, please excuse me for them being in Dutch; [t]http://puu.sh/ntrXE/1b6a221e63.png[/t][t]http://puu.sh/nts5c/daf7c8865f.png[/t] [t]http://puu.sh/nts9D/adea144b76.png[/t][t]http://puu.sh/ntsc0/9695977d37.png[/t] Also a link to the PDF file: [url]https://www.dropbox.com/s/j9pr10xiq8kcqt5/BMW-E12-vraagbaak-4-4.pdf?dl=0[/url] Electric stuff starts at page 23/47[/QUOTE]

Took apart a rubidium oscillator that was supposedly not producing any output, I however get a nicely locked 10MHz out of the thing. Fun. [media]http://imgur.com/a/6y9VL[/media]

I am currently collecting used li-ion 18650 cells, mostly from 'failed' laptop batteries. My idea is to make a test rig that tests the batteries and inserts the values and identity into a database. The goal is to cut down on the time used to separate the good cells from the bad cells. [IMG]https://dl.dropboxusercontent.com/u/100328/Facepunch/cells.jpg[/IMG]

Hello EEngineers! Is it possible that I power device through USB port (Android phone) and this USB is connection to USB HID (Mouse and Keyboad)?

[QUOTE=Fourier;49900293]Hello EEngineers! Is it possible that I power device through USB port (Android phone) and this USB is connection to USB HID (Mouse and Keyboad)?[/QUOTE] if the phone supports [URL="https://en.wikipedia.org/wiki/USB_On-The-Go"]USB OTG[/URL] fully, then yes.

Yeah I tested, I have USB OTG cable and Keyboard & Mouse works excellent. I just want to know, if I 'hack' this cable, can I apply 5V on rails from power source, because I don't want that Android device runs out of power.

[QUOTE=Fourier;49900340]Yeah I tested, I have USB OTG cable and Keyboard & Mouse works excellent. I just want to know, if I 'hack' this cable, can I apply 5V on rails from power source, because I don't want that Android device runs out of power.[/QUOTE] 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.

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_2834.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_2835.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_2845.jpg[/IMG] It's almost brand new. Frickin' beautiful. I've wanted a decent analog multimeter for ages!