Electrical Engineering V3 - Developers

[QUOTE=pentium;50091629]That feeling when you are a little over a day away from piles of free test equipment. It's like Christmas. AAAAAAAAAAAAAAAAAAAAAAAAAA.[/QUOTE] If they have any free scopes or other test equipment I'll take those off your hands.

Hey you Vancouver folks: Save your disposable COMPASS tickets, effective immediately. Word is spreading that while the plastic COMPASS cards have their encryption key set, [B]the tickets currently do not.[/B] The tickets can be readily dumped, or the data values indicating when the ticket was issued and for how many zones can be edited. There is an issue with serialization but of you're only out to clone your rechargeable card there shouldn't really be an issue so you can write to an NFC tag in your phone. [editline]mad chatter[/editline] [url=http://bc.ctvnews.ca/video?clipId=845979]Found a video on it.[/url]

Well time to stock up on them.

[QUOTE=Cakebatyr;50096963]If they have any free scopes or other test equipment I'll take those off your hands.[/QUOTE] While the ham swap meet was in the driveway there was a surprisingly small amount of free stuff this year. Not a lot of stuff aside from semiconductors, books and a few other odds and ends. The deals were apparently on the driveway where I got THESE TWO SEXY BITCHES FOR $10. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/59DA0058.jpg[/IMG] They both need work though. Anyways, there was also an Elmo overhead camera which I think will work well as a magnified soldering station and the rest was just booty. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/59DA0056.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/59DA0046.jpg[/IMG] Notable things: - Hp 3225A Function Generator (Throws an A-CAL FAIL) - Casio EA-100 sensor sets (now I just need a Casio graphing calculator) - Fluke stuff (one of the 8050A's was incomplete, so I'm keeping the other which is complete but has a fucked LCD....much like those two DMM's) - Assload of microcontroller development kits, mainly for the Zilog Z8 but there was also a box of Lantronix Xports - Bag of semiconductors. Literally, you filled the antistatic bag with as much as you could out of the bins and the whole bag was $2. - Tono EXL-5000E Radio Communications Terminal [url=http://www.universal-radio.com/catalog/decoders/EXL5000Emodes.jpg]which does just about everything.[/url] - A single 6BF7 vacuum tube, which is a one inch tall double triode.

Any of those Z8 dev kits functional? I may be interested.

They seem to be fairly complete but I'm actually meddling in a Z8 right now on an old Apple hard drive, so I might hold onto one of the kits. I don't need the multi-phase motor kit though.

Those 3225's are great bits of gear. Our's at our club gets daily use. The only big limiting factor on them is their frequency limit for the different functions.

It has to be better than my 651B at least.

[QUOTE=nuttyboffin;50095004][img]http://puu.sh/oaYZw/e709b6c617.jpg[/img][/QUOTE] hehe, check out what arrived at my school today [t]http://i.imgur.com/b1GcsnE.jpg[/t]

[QUOTE=Goz3rr;50129925]hehe, check out what arrived at my school today [t]http://i.imgur.com/b1GcsnE.jpg[/t][/QUOTE] All my envy.

Trying to find some Chinese fab house that can do semi-arbitrary soldermask colors for a medium run. I know dirtypcbs beta site is supposed to offer it, but that thing is pretty badly broken (can't select it). Can't find who the fuck their supplier is either.

[QUOTE=Tobba;50130618]Trying to find some Chinese fab house that can do semi-arbitrary soldermask colors for a medium run. I know dirtypcbs beta site is supposed to offer it, but that thing is pretty badly broken (can't select it). Can't find who the fuck their supplier is either.[/QUOTE] Semi-arbitrary? You could try hackvana, he offers a few colors. They of course cost extra, but it's like that everywhere.

Hackvana does green, red, blue, yellow, black and white.

I know PJRC managed to get some pink Teensy boards made for a special occasion, so I should probably just shoot them an email and ask what they did. I'm looking to get a violet/amaranth color inbetween pink and OSHparks purple. I assume the way those are done is by mixing differently colored soldermasks, but I think I'd need a run on the order of a few thousand square inches to convince anyone to muck with that. [editline]15th April 2016[/editline] Hackvana looks pretty decent for some reasonable-quality prototype boards though.

Pulled out the optical spectrum analyzer. Heard something rattling about inside. Couldn't find anything in the case. Sounded like it was coming from inside the optical assembly. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_1215.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_1216.jpg[/IMG] Hey! where did that mirror go? [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_1217.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_1218.jpg[/IMG] Oh. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/CGS_1219.jpg[/IMG] Yeah, this didn't work again. I salvaged some nice 12-bit A/D converters and the one-piece CRT module and sent the rest off to the makerspace for them to salvage the rest.

I've had plans and a BOM for making my own one of those sitting around for a long time that I never got around to making. Also those optical gratings are mad $$$.

I'm interested in frequency shift keying. Does anyone know any good technical papers on the subject? [editline]15th April 2016[/editline] Specifically interested in the effects of going from a continous to discrete signal

[QUOTE=proboardslol;50140039]I'm interested in frequency shift keying. Does anyone know any good technical papers on the subject? [editline]15th April 2016[/editline] Specifically interested in the effects of going from a continous to discrete signal[/QUOTE] [URL="http://www.eng.auburn.edu/~roppeth/courses/TIMS-manuals-r5/TIMS%20Experiment%20Manuals/Student_Text/Vol-D1/D1-07.pdf"]This[/URL] seems to be rather detailed for FSK. My [URL="http://web.eecs.utk.edu/~roberts/ECE342/AnalogCommunicationSystems.pdf"]professor's[/URL] [URL="http://web.eecs.utk.edu/~roberts/ECE342/"]notes[/URL] will be tangentially helpful and I can send you his textbook which covers more tangential/support notes if you'd like.

[QUOTE=LoneWolf_Recon;50140161][URL="http://www.eng.auburn.edu/~roppeth/courses/TIMS-manuals-r5/TIMS%20Experiment%20Manuals/Student_Text/Vol-D1/D1-07.pdf"]This[/URL] seems to be rather detailed for FSK. My [URL="http://web.eecs.utk.edu/~roberts/ECE342/AnalogCommunicationSystems.pdf"]professor's[/URL] [URL="http://web.eecs.utk.edu/~roberts/ECE342/"]notes[/URL] will be tangentially helpful and I can send you his textbook which covers more tangential/support notes if you'd like.[/QUOTE] The reason I wanted a paper specifically was because one of my final projects is to write a review of a technical paper

[QUOTE=proboardslol;50140039]I'm interested in frequency shift keying. Does anyone know any good technical papers on the subject? [editline]15th April 2016[/editline] Specifically interested in the effects of going from a continous to discrete signal[/QUOTE] While I'm approaching this from a ham perspective rather than an academic one, you could be looking at things such as Audio Frequency Shift Keying such as directly translating audio frequency to radio frequency. An example would be two audio tones spaced 170Hz apart ([B]R[/B]adio [B]T[/B]ele[B]TY[/B]pe) and then piped through a single sideband (carrier suppressed) modulation scheme. You're effectively using Amplitude Shift Keying to perform Frequency Shift Keying.

I got an ti n-spire calculator trackpad and I'm going to communicate with it using a microcontroller, should I solder jumper wire to the pins or use a connector which I'll solder to. I don't know what kind of connector it would use, looks like the same kinda slot on a pc like a pci slot. Sorry that I don't know all of my connectors. [url=http://www.ebay.com/itm/TI-Nspire-Touchpad-Key-Pad-Genuine-TI-Product-Excellent-Condition-Touch-Keypad-/281777067545?hash=item419b38d619:g:-~MAAOSwu4BV08GX]ebay link[/url] example of trackpad, third image to the right.

Hey guys, my buck converter keeps plaguing me. I'm using a MAX1651 chip with a 47uH inductor, FERD20M60 flyback diode, 330uF output capacitance and a SI9435BDY p-channel mosfet, with the VFB set by (According to the datasheet: R3 = 3k, R2 = 24k). Needless to say my Vout should be ~13.5V but instead its resulting ~130mV when loaded (270 ohm resistor) and 1.1V when unloaded. Any ideas?

[QUOTE=LoneWolf_Recon;50162831]Hey guys, my buck converter keeps plaguing me. I'm using a MAX1651 chip with a 47uH inductor, FERD20M60 flyback diode, 330uH output capacitance and a SI9435BDY p-channel mosfet, with the VFB set by (According to the datasheet: R3 = 3k, R2 = 24k). Needless to say my Vout should be ~13.5V but instead its resulting ~130mV when loaded (270 ohm resistor) and 1.1V when unloaded. Any ideas?[/QUOTE] What value current sense resistor are you using ? What is your input voltage ? I assume you're not doing this on a breadboard ? Double check your pinout.

[QUOTE=Chryseus;50163149]What value current sense resistor are you using ? What is your input voltage ? I assume you're not doing this on a breadboard ? Double check your pinout.[/QUOTE] Here's my [URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/SLA_Main_Charge_Controller.pdf"]schematic[/URL] & [URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/SLA_Main_Charge_BOM.csv?attredirects=0&d=1"]BOM[/URL], I'm running it on my own PCB and all the nets check out with the schematic, continuity checks out with my meter. Input voltage is a flat 15VDC. Current sense resistor is 75mOhms. Also I shunted the SHDN pin to ground, (Thus enabling the buck controller) bypassing my microcontroller for the time being. Thank you!

[QUOTE=LoneWolf_Recon;50163944]Here's my [URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/SLA_Main_Charge_Controller.pdf"]schematic[/URL] & [URL="https://sites.google.com/site/lonewolfscircuits/sitefiles/SLA_Main_Charge_BOM.csv?attredirects=0&d=1"]BOM[/URL], I'm running it on my own PCB and all the nets check out with the schematic, continuity checks out with my meter. Input voltage is a flat 15VDC. Current sense resistor is 75mOhms. Also I shunted the SHDN pin to ground, (Thus enabling the buck controller) bypassing my microcontroller for the time being. Thank you![/QUOTE] I can't see any problems with your schematic or component selection. The only thing I can think of is U1 or Q1 is faulty, or there is a problem with one of your footprints. I would definitely check the drive waveform of Q1 and double check the current sense resistor.

Been working in the clean room and on a fabrication process this semester to build an IGBT and a Half-Adder created with NOR gates. This picture is a bit old, it was after the n+ implantation of arsenic. Hopefully should have better pictures soon after the fab is done [thumb]http://files.1337upload.net/Device_Post_Nplus-9cc9f3.png[/thumb] It's 5 NOR gates with the PMOS on the left and NMOS on the right

[QUOTE=Hazrd24;50167538]Been working in the clean room and on a fabrication process this semester to build an IGBT and a Half-Adder created with NOR gates. This picture is a bit old, it was after the n+ implantation of arsenic. Hopefully should have better pictures soon after the fab is done [thumb]http://files.1337upload.net/Device_Post_Nplus-9cc9f3.png[/thumb] It's 5 NOR gates with the PMOS on the left and NMOS on the right[/QUOTE] How high of a current IGBT do you think you could make?

If I want to run something like a ATtiny84V, three 7seg displays a button to wake it off AA batteries as long as possible. According to the datasheet it requires 1.8 – 5.5V to run, what would be the best way to achieve this? I'm thinking just putting 2 AA batteries in series to create 3V, would it be worth it to add a boost converter to keep it running slightly longer? I'm also unable to figure out what happens to the IO pin voltage, is it just equal to VCC or is it regulated?

[QUOTE=Chryseus;50167456]I can't see any problems with your schematic or component selection. The only thing I can think of is U1 or Q1 is faulty, or there is a problem with one of your footprints. I would definitely check the drive waveform of Q1 and double check the current sense resistor.[/QUOTE] Turns out the bench supply I was using ([URL="http://www.mouser.com/ProductDetail/Mean-Well/LRS-75-15/?qs=sGAEpiMZZMsPs3th5F8koMf%2fa2V0paI94T8aNLo%2fpZTU2e1ZEracag%3d%3d"]One of those cheap AC to DC converters[/URL]) was superimposing a 20VAC signal on top of the 15VDC, my meter didn't pick it up but the scope did and that's what killed the buck controller. Replaced the buck controller and connected Vin to a proper bench supply, needless to say it's working just fine! (Although it is arcing a bit when I connect it, should I put a PTC in series?) Thanks for the help. [QUOTE=Hazrd24;50167538]Been working in the clean room and on a fabrication process this semester to build an IGBT and a Half-Adder created with NOR gates. This picture is a bit old, it was after the n+ implantation of arsenic. Hopefully should have better pictures soon after the fab is done It's 5 NOR gates with the PMOS on the left and NMOS on the right[/QUOTE] What lithography are you working at and equipment? My current VLSI classes has me designing at 600nm. (With the entire class getting all our flip flops being fabbed). [editline]20th April 2016[/editline] [QUOTE=Goz3rr;50170561]If I want to run something like a ATtiny84V, three 7seg displays a button to wake it off AA batteries as long as possible. According to the datasheet it requires 1.8 – 5.5V to run, what would be the best way to achieve this? I'm thinking just putting 2 AA batteries in series to create 3V, would it be worth it to add a boost converter to keep it running slightly longer? I'm also unable to figure out what happens to the IO pin voltage, is it just equal to VCC or is it regulated?[/QUOTE] The IO pin voltage is equal to VCC, you can use two AAs to supply the entire thing as the minimum voltage would drop to 2V, well within the range of the ATtiny. However I tend to not like hinging it off battery power alone, thus I'd recommend a basic boost converter to bump it to say 3.3V.

[QUOTE=LoneWolf_Recon;50170579]Replaced the buck controller and connected Vin to a proper bench supply, needless to say it's working just fine! (Although it is arcing a bit when I connect it, should I put a PTC in series?) Thanks for the help.[/QUOTE] You mean a NTC thermistor ? In any case 330uF is quite low so I'd not worry about it. Another alternative would be to put an inductor in series, although that can end up more expensive than a thermistor, I'm not entirely sure how good a thermistor would work in low voltage circuits, you'd have to find one with a fairly low cold resistance.