Electrical Engineering V3

[DrLuke]

[QUOTE=nuttyboffin;50930279]Y'd think for the price of the unit that they would use better cable management techniques.[/QUOTE]

Like what? It seems pretty solid to me

[Ddrl46]

[QUOTE=nuttyboffin;50930279]Y'd think for the price of the unit that they would use better cable management techniques.[/QUOTE]

This network analyzer has been apart a few times before, I wouldn't be surprised if a few of the cables have been moved around. It probably looked a lot neater originally.

Unless you mean the rigid coaxes that is.

[GaryJS]

[QUOTE=paindoc;50929592]Don't look at the schematic for the RAMPS board, its pretty much as bad as a design can be. The thing just about [I]literally[/I] couldn't be made ot be noisier.

Drivers are a common point of failure. Make sure they aren't overheating and set your current to be the minimum it can be for the drivers to move, too. Microstepping being too high can increase current draw too - 1/16th is the highest you should be on a RAMPS board.

If you can, move to something like smoothieboard soon. Smoothie firmware is seeing a lot of use now and is being adopted by a number of other board manufacturers, and there are even smoothieboard clones. The firmware update process is way easier for these boards, and the config files can be unchanged between firmware updates.

They also have software trimpots, so you use your stepper motor spec sheets to set the current draw in your config file. Combine that with thermal vias that aren't retarded, and the smoothieboard won't eat any drivers.

[editline]22nd August 2016[/editline]

if you have any further questions about 3d printing hmu. its pretty much my entire job to maintain our companies 7 3D printers, from monoprice clones, ultimakers, repraps, to a really big proprietary machine[/QUOTE]

Unfortunately, I've already seen it. Lol. And I really appreciate the advice. I will look into swapping the main board as my first upgrade when I get to that point. I'm still getting familiar with all this 3D printing stuff.

[GaryJS]

So, an electrical question.

For [URL="http://garyjs.com/MicroMFD"]my truck data display[/URL]. I am going to have a pin from the fuel gauge goto an analog pin on my arduino. The voltage divider created by the probe and gauge actually keeps it under 5V. But, it's still an unregulated power supply feeding that gauge. I feel I should either control the power supply with a regulator or electrically isolate the two. My gauge is a bimetallic strip, so it's position is based on how much current flows through the fuel sender ( a potentiometer ) to ground.

I feel the power regulation would be best as it would ensure a stable signal regardless of the truck's power state (running,off,etc) and it would also protect the arduino.

I have to be careful if I used something to isolate, as any path to ground will cause the gauge to be inaccurate.

This is the diagram
[IMG]http://i.imgur.com/igUd7Tx.png[/IMG]

Any thoughts? Maybe ideas on how you guys might do it? Does my idea sound good? Just nice to get some input as I'm not a god-teir electrical person.

[Chryseus]

As long as the current in to the pin is limited, say with a 10k series resistor it doesn't matter if you exceed the supply rail of the microcontroller since the internal diodes will clamp the voltage to a safe level.

[Van-man]

[QUOTE=gjsdeath;50934814]So, an electrical question.

For [URL="http://garyjs.com/MicroMFD"]my truck data display[/URL]. I am going to have a pin from the fuel gauge goto an analog pin on my arduino. The voltage divider created by the probe and gauge actually keeps it under 5V. But, it's still an unregulated power supply feeding that gauge. I feel I should either control the power supply with a regulator or electrically isolate the two. My gauge is a bimetallic strip, so it's position is based on how much current flows through the fuel sender ( a potentiometer ) to ground.

I feel the power regulation would be best as it would ensure a stable signal regardless of the truck's power state (running,off,etc) and it would also protect the arduino.

I have to be careful if I used something to isolate, as any path to ground will cause the gauge to be inaccurate.

This is the diagram
[IMG]http://i.imgur.com/igUd7Tx.png[/IMG]

Any thoughts? Maybe ideas on how you guys might do it? Does my idea sound good? Just nice to get some input as I'm not a god-teir electrical person.[/QUOTE]

I'd also hook up the arduino to the battery via a 4-to-1 resistor ladder (so 12 volt gets divided by 4, this is to compensate for voltage spikes during cranking) and a 5.1volt zener after the resistor ladder (and the mandatory fuse before it all).

Probably also a 5.1v zener for the fuel gauge hookup, optionally with a buffer op-amp before it for reducing impendance disturbtion of the fuel sender output.

That way you can voltage drop/spike compensate with a little bit of math on the arduino, and optionally also have a display for battery/alternator voltage.

[GaryJS]

[QUOTE=Van-man;50935215]I'd also hook up the arduino to the battery via a 4-to-1 resistor ladder (so 12 volt gets divided by 4, this is to compensate for voltage spikes during cranking) and a 5.1volt zener after the resistor ladder (and the mandatory fuse before it all).

Probably also a 5.1v zener for the fuel gauge hookup, optionally with a buffer op-amp before it for reducing impendance disturbtion of the fuel sender output.

That way you can voltage drop/spike compensate with a little bit of math on the arduino, and optionally also have a display for battery/alternator voltage.[/QUOTE]

I can actually measure the battery/power voltage via the adapter at any time, since it has an ADC on that chip and does just that. I did actually consider the compensation, I just thought a regulator would be cleaner. I think I'll just try compensating and if it ends up being inaccurate or unreliable I'll add a regulator (along with an indicator LED so I know my regulator and by extension my gauge is functioning).

I think I'll end up with a 10K resistor (thanks Chryseus) and a 5.1V zener diode (thanks Vanman).

As for operation, I considered the system to simply turn off the display a few minutes after the vehicle has been turned off and can be turned on by pressing any key. This can also allow the Bluetooth module and OBD adapter to stay connected all the time, so it doesn't have to waste time connecting every time. I'll put a transistor along with a cap so the arduino can power cycle the Bluetooth module, the idea behind a cap would be to hold the transitior on in case I need the arduino to reset without having to make the bt module reconnect. You guys think an arduino could survive being on all the time in my truck in Florida weather? Would being on and hot as shit kill it? Would a little fan help?

[pentium]

[url=http://www.ebay.com/sch/electron-bg/m.html?item=252513483891&rt=nc&_trksid=p2047675.l2562]Bulgaria is currently having a sale. Look at all those cool and cheap parts.[/url]

[editline]SDAfas[/editline]

Oh fuck. Wrong link. Fixed.

[AuntJimmy]

So I fucked up

[img]https://i.imgur.com/vZy2pkV.jpg[/img]

First time doing surface mount soldering, and as you can see I have no idea what I'm doing

Several times I added a little too much solder to a pad and now there are all these really thin puddles that I can't figure out how to remove

Even better, when I measure the resistance across any resistor (they're supposed to be 10k), I get about 7k, and the resistance very slowly increases

help

[nikomo]

Use a solder wick or solder sucker to remove the solder.
You might have also cooked the resistors, by heating them for too long. SMD soldering is supposed to be very quick, when you do it manually by hand.

[MadsAG]

SMD soldering without solder mask and plated pads is hell.

The procedure for SMD soldering is: Apply solder to one pad. Take your component and heat up the solder again, as you position the one leg/side in the solder. Make sure the component is flush to the PCB.

Then solder down the other side, and go back and resolder the first pad again, so that you get proper flux and heat to that leg/side.

[AuntJimmy]

I followed a pretty similar version of that procedure, what ended up happening was I applied a bit too much solder to the pad initially, and it just spilled everywhere. Tried a solder sucker, but the solder was so thin that I couldn't melt enough of it to really make a difference. Similar issue with solder wick, it wouldn't get that much solder off.

I wouldn't be surprised if I inadvertently cooked the resistors when I was trying to get the solder off. When I was actually trying to get the resistors in, I was only working with light taps of the soldering iron.

[Ddrl46]

[QUOTE=halofreak472;50961864]I followed a pretty similar version of that procedure, what ended up happening was I applied a bit too much solder to the pad initially, and it just spilled everywhere. Tried a solder sucker, but the solder was so thin that I couldn't melt enough of it to really make a difference. Similar issue with solder wick, it wouldn't get that much solder off.

I wouldn't be surprised if I inadvertently cooked the resistors when I was trying to get the solder off. When I was actually trying to get the resistors in, I was only working with light taps of the soldering iron.[/QUOTE]

You won't be getting rid of those very thin solder "puddles", once the molten solder has touched the copper you'll never be getting rid of all of it.

For SMD soldering in general you should be getting thin solder, preferably 0.5mm or less. Also get a flux pen or flux paste or whatever. It'll make your life a lot easier. Do not try to do SMD soldering with a conical tip, do yourself a favor and use a small chisel tip.

[Chryseus]

You have to be very careful when soldering SMD without a solder mask, I use 0.5mm solder and only a tiny tiny amount of solder is needed, flux either in liquid or paste is also a must since you want transfer it from the tip to the pad any flux in the solder will be burned off before it can be used.
With some practice it's pretty easy to do 0603 and perhaps even smaller.

[kokonut]

I used to use 0.23mm when I soldered small smd components, really easy to get just the right amount of solder

[DrLuke]

I just apply flux to the board and put a solder blob on my iron, and then touch the pins. Works perfectly.

[proboardslol]

Could you design a circuit using lasers, fiber optic cables, and solar cells to produce logic gates, potentially creating faster circuits than with copper wires?

[LoneWolf_Recon]

[QUOTE=proboardslol;50968111]Could you design a circuit using lasers, fiber optic cables, and solar cells to produce logic gates, potentially creating faster circuits than with copper wires?[/QUOTE]

[URL="http://electronics.stackexchange.com/questions/100857/laser-diode-to-remove-copper-layer-from-pcb"]Yes, but its expensive af.[/URL]

[paindoc]

[QUOTE=halofreak472;50961396]So I fucked up

[img]https://i.imgur.com/vZy2pkV.jpg[/img]

First time doing surface mount soldering, and as you can see I have no idea what I'm doing

Several times I added a little too much solder to a pad and now there are all these really thin puddles that I can't figure out how to remove

Even better, when I measure the resistance across any resistor (they're supposed to be 10k), I get about 7k, and the resistance very slowly increases

help[/QUOTE]

My first attempt at soldering SMD was bad enough our COO called me out for it instantly and said we couldn't use this board near customers :v:

[nikomo]

[QUOTE=proboardslol;50968111]Could you design a circuit using lasers, fiber optic cables, and solar cells to produce logic gates, potentially creating faster circuits than with copper wires?[/QUOTE]

Not exactly what you're thinking of, but photonic integrated circuits are actively being researched.

[DrLuke]

[QUOTE=nikomo;50971733]Not exactly what you're thinking of, but photonic integrated circuits are actively being researched.[/QUOTE]

My university does it: [url]http://www.kit.edu/kit/english/pi_2016_059_nature-photonics-light-source-for-quicker-computer-chips.php[/url]

[DrLuke]

I just sniped this scope: [url]http://www.ebay.de/itm/232064446792[/url]

[DrLuke]

The mushrooms move, [url=https://www.youtube.com/watch?v=rtR63-ecUNo]just like in real life[/url]:

[t]https://my.mixtape.moe/tjapnx.JPG[/t]

[Van-man]

[QUOTE=DrDevil;51005065]The mushrooms move, [url=https://www.youtube.com/watch?v=rtR63-ecUNo]just like in real life[/url]:

[t]https://my.mixtape.moe/tjapnx.JPG[/t][/QUOTE]

I feel like I should've been on acid while watching the latter part of that video.

[proboardslol]

I bought a 12v DC power supply and have a dozen+ meters of led strip lights that I want to solder end to end. Is there any universe in which I could hurt myself this way (electrically. I know I can burn myself with a soldering iron)

[Dolton]

[QUOTE=proboardslol;51012001]I bought a 12v DC power supply and have a dozen+ meters of led strip lights that I want to solder end to end. Is there any universe in which I could hurt myself this way (electrically. I know I can burn myself with a soldering iron)[/QUOTE]

Overload the power supply power rating and possibly cause some smoke. Start a fire if the power supply voltage is too high and burns out the LED's. Other than that, you're not going to get electrically harmed by 12 volts. Fires and heat should be your biggest concern.

[MadsAG]

[QUOTE=proboardslol;51012001]I bought a 12v DC power supply and have a dozen+ meters of led strip lights that I want to solder end to end. Is there any universe in which I could hurt myself this way (electrically. I know I can burn myself with a soldering iron)[/QUOTE]

Solder end to end? That is not going to end well. If more than 2,5 meter long then i recommend soldering wires to both ends. If more than 5M then I'd recommend attaching wires in the middle.

The issue here is voltage drop, which means the LEDs far from the output will be way dimmer.

EDIT:
I found this, I've no idea what the article says as I haven't read it- but I can vouch for the pictures/diagrams.
[url]https://blog.adafruit.com/2011/12/27/new-year%E2%80%99s-disco-ball-powering-the-beast/[/url]

[hakkoru]

[QUOTE=elitehakor;50915739]idk i really enjoyed using fpgas

[editline]19th August 2016[/editline]

oh hey since i have money now i might buy that cheap fpga i was eyeing

[editline]19th August 2016[/editline]

[img]http://i.imgur.com/YfxRWef.png[/img]

excellent[/QUOTE]

i finally got it

time to install parallels so i can get windows 7 on my mbp

[editline]7th September 2016[/editline]

also we got our first project in my adv computer architecture class: design a synthesizable program in verilog that averages two 8 bit unsigned ints and rounds up without using the + or bit shift operators. seems simple enough

[proboardslol]

[QUOTE=elitehakor;51016880]i finally got it

time to install parallels so i can get windows 7 on my mbp

[editline]7th September 2016[/editline]

also we got our first project in my adv computer architecture class: design a synthesizable program in verilog that averages two 8 bit unsigned ints and rounds up without using the + or bit shift operators. seems simple enough[/QUOTE]

wait you didn't go with the UPS express?

[LoneWolf_Recon]

I've been working on this for awhile, it was a pain in the butt to find a transformerless EL driver that can drive up to a foot of EL Wire.

Costuming/Gaming Controller Glove!

[video=youtube;X0YdSWUp4qo]http://www.youtube.com/watch?v=X0YdSWUp4qo[/video]