Electrical Engineering V3

[LoneWolf_Recon]

[QUOTE=DrDevil;49068532]"We need the range". You can get several of hundreds of kilometers range with a 10mW 433 MHz transceiver which is like 20 bucks on ebay.

You should also use a second mode of communication that can also be listened to by people without specific hardware, for example APRS. APRS is moderately easy to implement and had wide coverage around the globe. You can't push more than a few bytes of data over it, but it's perfect for regular position updates so you can find the balloon after landing.[/QUOTE]

To be fair, you have a point as the lower frequency would be less absorbed and have a lower free space loss than at 900MHz (At 433MHz/30KM the loss param is 116.4dB, At 900MHz/30KM: 122.8dB). Weather permitting a clear day.

If we considered a [URL="http://www.ebay.com/itm/USB-to-TTL232-Wireless-RF-Data-Transceiver-Module-10mW-UART-MAX232-RS232-CC1101-/281033720857?_trksid=p2141725.m3641.l6368"]10mW transceiver like such[/URL] with a 10dBm transmitter + 2.1dBi dipole, the receiving end sensitivity would need to be atleast -104.3dBm. Which that [URL="http://www.ti.com/lit/ds/swrs061i/swrs061i.pdf"]transceiver's chip[/URL] can take just fine at 38400 baud, well above our 9600 baud target.

Conversely, the [URL="https://www.sparkfun.com/datasheets/Wireless/Zigbee/xtend-datasheet.pdf"]Digi Xtend 900[/URL] module with 32dBm (1W) and a 2.1dBi dipole would need to be sensitive to atleast -88.7dBm which it can accomplish -110dBm sensitivity at 9600 baud...

:suicide:

Christ I feel idiotic...I guess we paid for licensing fees. And I'm just fighting myself by using a higher frequency. But thankfully these radios are going to be reused for our later projects, the end goal being a CubeSat/500KM alt. Which would require a 15dBi antenna on the ground at the minimum.

Any recommendations on APRS modules? The most promising I've found so far are [URL="http://www.byonics.com/microtrak/"]Micro-Traks[/URL]. Thank you for the help.

[Ddrl46]

Got some swapmeet loot,

HP 400E AC Voltmeter:
[url=http://i.imgur.com/LNESdj9.jpg][img]http://i.imgur.com/LNESdj9l.jpg[/img][/url]
[url=http://i.imgur.com/XgzvHvL.jpg][img]http://i.imgur.com/XgzvHvLl.jpg[/img][/url]

HP 355D 120dB Step Attenuator, HP 8494A 11dB Step Attenuator and two Krytar 301AP 20GHz RF detectors.
[url=http://i.imgur.com/SQrOhEl.jpg][img]http://i.imgur.com/SQrOhEll.jpg[/img][/url]

[paindoc]

[QUOTE=LoneWolf_Recon;49070130]To be fair, you have a point as the lower frequency would be less absorbed and have a lower free space loss than at 900MHz (At 433MHz/30KM the loss param is 116.4dB, At 900MHz/30KM: 122.8dB). Weather permitting a clear day.

If we considered a [URL="http://www.ebay.com/itm/USB-to-TTL232-Wireless-RF-Data-Transceiver-Module-10mW-UART-MAX232-RS232-CC1101-/281033720857?_trksid=p2141725.m3641.l6368"]10mW transceiver like such[/URL] with a 10dBm transmitter + 2.1dBi dipole, the receiving end sensitivity would need to be atleast -104.3dBm. Which that [URL="http://www.ti.com/lit/ds/swrs061i/swrs061i.pdf"]transceiver's chip[/URL] can take just fine at 38400 baud, well above our 9600 baud target.

Conversely, the [URL="https://www.sparkfun.com/datasheets/Wireless/Zigbee/xtend-datasheet.pdf"]Digi Xtend 900[/URL] module with 32dBm (1W) and a 2.1dBi dipole would need to be sensitive to atleast -88.7dBm which it can accomplish -110dBm sensitivity at 9600 baud...

:suicide:

Christ I feel idiotic...I guess we paid for licensing fees. And I'm just fighting myself by using a higher frequency. But thankfully these radios are going to be reused for our later projects, the end goal being a CubeSat/500KM alt. Which would require a 15dBi antenna on the ground at the minimum.

Any recommendations on APRS modules? The most promising I've found so far are [URL="http://www.byonics.com/microtrak/"]Micro-Traks[/URL]. Thank you for the help.[/QUOTE]

The same night I almost went on a eBay shopping spree I constructed a great wishlist of books I wanted for my birthday, and it includes [URL="http://www.amazon.com/gp/product/1449310664?colid=1QPSKLCVC0MS6&coliid=I10HW4OGVYRSCW&ref_=wl_it_dp_o_pC_nS_ttl"]this [/URL]

It may be of some use to you, and the Kindle version is 3.50 and you can read these ond esktop. Look at the preview maybe and see if it helps a bit. There's a whole series of these books too.

[editline]7th November 2015[/editline]

Fluke has kitted out a makerspace on our campus fully, and when I was there last it had just opened. Its fully up and running now and holy shit you should see the test bench and the pcb fabrication ahrdware they have.

That and a box full of dozens of really nice Fluke Multimeters just sitting around for sale for super cheap to club employees and long-term members :o

[Cakebatyr]

[QUOTE=LoneWolf_Recon;49070130]To be fair, you have a point as the lower frequency would be less absorbed and have a lower free space loss than at 900MHz (At 433MHz/30KM the loss param is 116.4dB, At 900MHz/30KM: 122.8dB). Weather permitting a clear day.

If we considered a [URL="http://www.ebay.com/itm/USB-to-TTL232-Wireless-RF-Data-Transceiver-Module-10mW-UART-MAX232-RS232-CC1101-/281033720857?_trksid=p2141725.m3641.l6368"]10mW transceiver like such[/URL] with a 10dBm transmitter + 2.1dBi dipole, the receiving end sensitivity would need to be atleast -104.3dBm. Which that [URL="http://www.ti.com/lit/ds/swrs061i/swrs061i.pdf"]transceiver's chip[/URL] can take just fine at 38400 baud, well above our 9600 baud target.

Conversely, the [URL="https://www.sparkfun.com/datasheets/Wireless/Zigbee/xtend-datasheet.pdf"]Digi Xtend 900[/URL] module with 32dBm (1W) and a 2.1dBi dipole would need to be sensitive to atleast -88.7dBm which it can accomplish -110dBm sensitivity at 9600 baud...

:suicide:

Christ I feel idiotic...I guess we paid for licensing fees. And I'm just fighting myself by using a higher frequency. But thankfully these radios are going to be reused for our later projects, the end goal being a CubeSat/500KM alt. Which would require a 15dBi antenna on the ground at the minimum.

Any recommendations on APRS modules? The most promising I've found so far are [URL="http://www.byonics.com/microtrak/"]Micro-Traks[/URL]. Thank you for the help.[/QUOTE]

Check out the source code for the Mobilinkd APRS unit (its an Atmega328), it relies on the KISS protocol between itself and the phone to form packets, but it still generates the APRS tones itself and can probably just be hooked up to a cheapo GPS unit. Alternatively look into the [url=https://www.tracksoar.com]TrackSOAR[/url] and maybe contact the guy doing [url=https://www.reddit.com/r/amateurradio/comments/3isr9g/i_just_launched_a_diy_2_gram_highaltitude_balloon/]FeatherHAB[/url].

Also I took my Amateur Radio Advanced test today and passed it!

[Papkee]

[QUOTE=Cakebatyr;49072710]
Also I took my Amateur Radio Advanced test today and passed it![/QUOTE]

Welcome to the world's most addictive and expensive hobby.

[Cakebatyr]

[QUOTE=papkee;49073964]Welcome to the world's most addictive and expensive hobby.[/QUOTE]

I got my Basic with Honours back in January, this merely means I can do fun stuff like run stupid amounts of power and found clubs and repeaters.

Also my shack: [T]http://i.imgur.com/yfpE5Aw.jpg[/T]

I'm already aware of the costs.

[Chryseus]

[QUOTE=papkee;49073964]Welcome to the world's most addictive and expensive hobby.[/QUOTE]

As far as hobbies go electronics is pretty cheap, you can get a decently equipped lab for under £1000.

[pentium]

This is expensive if you suck at being creative.

EG: "How to make an LED blink"

[img]http://cdn.instructables.com/F2K/PTED/I3VHJH1H/F2KPTEDI3VHJH1H.MEDIUM.jpg[/img]

[woidoi]

I got a pair of [URL="http://www.dx.com/p/arduino-apc220-wireless-rf-modules-w-antennas-usb-converter-143011"]these rf modules[/URL] that I can't get working anymore. I bought them two years ago and they worked fine then, but they refuse to work whenever I try them nowadays, and I double checked all settings on them. They do still get detected when plugged in using the usb converter, but I can't seem to receive/transmit data anymore.

They do have a crystal, so maybe I dropped one at some point causing that to break. Would it be easy to identify a broken crystal without an oscilloscope at hand?

[paindoc]

[QUOTE=Chryseus;49076171]As far as hobbies go electronics is pretty cheap, you can get a decently equipped lab for under £1000.[/QUOTE]

not to mention most electronics work makes me feel like I chose to spec repair or science in Fallout

Buy new shit? Fuck it, make my own. Something broken? Fix it. Something new? Lets kludgineer the shit out of this! Also if the apocalypse happens and we somehow survive unlike 99%+ of the earth we can sell our knowledge for power

I don't even like Fallout or care about FO4 why is this on my mind

[Papkee]

I was referring more towards amateur radio as opposed to electronics in general.

Try getting a well-equipped ham shack for under $1000. It's doable but you'll have to make plenty of compromises in regards to antennas, power, equipment, etc.

But it is damn fun once you have stuff to play with.

[Zero-Point]

[QUOTE=pentium;49076271]This is expensive if you suck at being creative.

EG: "How to make an LED blink"

[img]http://cdn.instructables.com/F2K/PTED/I3VHJH1H/F2KPTEDI3VHJH1H.MEDIUM.jpg[/img][/QUOTE]

Where is your current-limiting resistor, mister?

[Ddrl46]

[QUOTE=Zero-Point;49078832]Where is your current-limiting resistor, mister?[/QUOTE]

They are probably using one of those LEDs with built in current limiting resistor, cheaters...

[paindoc]

the true spirit of arduino's is saying "fuck it" and going for it since you bought a ten pack from ebay

all fun and games until you run 12amps into the 5v reg of an Arduino Nano. [I]That[/I] was spectacular and worth the money even if the magic smoke got out

[Zero-Point]

[QUOTE=ddrl46;49079110]They are probably using one of those LEDs with built in current limiting resistor, cheaters...[/QUOTE]

Damn kids these days, don't know how good they got it.

[DrLuke]

[QUOTE=LoneWolf_Recon;49070130]
Any recommendations on APRS modules? The most promising I've found so far are [URL="http://www.byonics.com/microtrak/"]Micro-Traks[/URL]. Thank you for the help.[/QUOTE]

I once just implemented it myself using an stm32f0 mcu. It has a a built-in 10-bit DAC to generate the 2 tones with phase continuity. Then I fed the tone into this transmitter: [url]http://www.radiometrix.com/node/379[/url]

I was transmitting with some el cheapo whip antenna connected via a bodged on SMA connector, and our university's APRS beacon picked it up over a distance of 1km and with several buildings inbetween.

[Chryseus]

[t]http://i.imgur.com/45IVCek.jpg[/t]
Not bad for a little under £100 plus shipping from Germany.

[DrLuke]

[QUOTE=Chryseus;49085718][t]http://i.imgur.com/45IVCek.jpg[/t]
Not bad for a little under £100 plus shipping from Germany.[/QUOTE]

Is it still in calibration?

[Chryseus]

[QUOTE=DrDevil;49085927]Is it still in calibration?[/QUOTE]

As far as I can tell it's very close, last cal was 2005.

[Ddrl46]

[QUOTE=Chryseus;49085718][t]http://i.imgur.com/45IVCek.jpg[/t]
Not bad for a little under £100 plus shipping from Germany.[/QUOTE]

Philips multimeter of more or less the same series bros!
[url=http://i.imgur.com/y8qshLO.jpg][img]http://i.imgur.com/y8qshLOl.jpg[/img][/url]

[url=http://i.imgur.com/7rmHejj.jpg][img]http://i.imgur.com/7rmHejjl.jpg[/img][/url]
(Ignore offset on the calibration generator, I adjusted it spot on with a known good meter)

[DrLuke]

I made a PCB

[t]https://my.mixtape.moe/uswctq.png[/t]

[url]http://gerblook.org/pcb/C6R5gyF87C4CTyYbipbYKQ[/url]

Any criticism or suggestions?

[LoneWolf_Recon]

[QUOTE=DrDevil;49089883]I made a PCB

[t]https://my.mixtape.moe/uswctq.png[/t]

[url]http://gerblook.org/pcb/C6R5gyF87C4CTyYbipbYKQ[/url]

Any criticism or suggestions?[/QUOTE]

why.

[sp]Its beautiful, a masterpiece, a gate driver or what am I looking at...?[/sp]

[TCWilliamson]

[QUOTE=DrDevil;49089883]I made a PCB

[t]https://my.mixtape.moe/uswctq.png[/t]

[url]http://gerblook.org/pcb/C6R5gyF87C4CTyYbipbYKQ[/url]

Any criticism or suggestions?[/QUOTE]

Buy yourself a new mouse it seems drunk or blind... possibly both.

[DrLuke]

[QUOTE=LoneWolf_Recon;49090275]why.

[sp]Its beautiful, a masterpiece, a gate driver or what am I looking at...?[/sp][/QUOTE]

On the left are 2 inputs for APA102C LED strips, on the right are two outputs. The controller in the middle intercepts the data packets coming in, and manipulates them, behaving like a router.

[Cakebatyr]

[QUOTE=nuttyboffin;49090409]Buy yourself a new mouse it seems drunk or blind... possibly both.[/QUOTE]

100% guarantee that the electrons will not fall off those traces.

[Fourier]

[QUOTE=DrDevil;49089883]I made a PCB

[t]https://my.mixtape.moe/uswctq.png[/t]

[url]http://gerblook.org/pcb/C6R5gyF87C4CTyYbipbYKQ[/url]

Any criticism or suggestions?[/QUOTE]

Lovely, almost like an art :)

[Falcqn]

Curved traces? On a PCB? You're a madman.

[DrLuke]

[QUOTE=Falcqn;49092368]Curved traces? On a PCB? You're a madman.[/QUOTE]

It's for HF reasons, you wouldn't understand

[paindoc]

So I got more into my orbital computer program, then realized that what I was doing was a bit silly. For one, I didn't know that math as well as I thought I did :v:

And two I do what I tend to do as of late, overcommit to projects. The problem with having medication that gives you the ability to actually [I]do[/I] things and be productive instead of just dream of being productive is that having this sudden surplus of ability+motivaition means I can never get a good realistic guess of how much time I actually have committed to my projects. Here's what I thought I was capable of doing: keep working on my music production and music learning, 15 credit hours of schoolwork with 3.0+ hopeful gpa, club officership, revamp club website, lead electronics design team for undergrad huge 3d printer research, help with 3d scanning actual godddanm dinosaur bones to 3d print (!!!!), work on synth project, build orbital computer, program orbital computer, etc. Oops.

So instead back to just the one project, our DSP+FPGA+VA+actuallyanalog synthesizer mad science platform. Halofreak has been chuggin along on his own analog circuitry (choosing his own custom circuit, and the hard way, over the easy tried and true way haha). I'm pretty excited to try this FPGA stuff, I'm probably going to dump my birthday money not reserved for housing this summer into this project. Does anyone have any recommendations on figuring out what sort of FPGA board I'll need? Not sure how many logic devices I'll actually need. I'd like to try emulating the classic roland synths as my first "learn to program and design for fpga's" project, since I have the schematics of the Big 3 retro's printed out on cardstock.

Also not sure what I'll need for audio conversion, I don't want to put way too much money into stuff thats layered with marketing-speak but having an audio board thats high enough quality (24bit+44.1kHz at least) to use in our final product would be nice. Noise is gonna be a bitch, though, with our VCO design afaik.

halofreak472 i summon thee help

[Richy13]

What are some good practices for programming arduino? Am I OK to use classes? Should I avoid new/delete...