/diy/ - Do It Yourself

>>137509
The time it takes for the cap to become charged is dependent on its capacity and the current feeding it. I never stated those values so you have no basis for stating it would take microseconds. I would still call microseconds "slowly" given the relative speed of most things in electronic circuits, and to emphasize that a capacitor can discharge faster than it charges.

if I wanted to be totally anal about capacitor charge times I could point out that capacitors never technically reach full capacity because their rate of increase decays exponentially.

>>137502
Please stop taking my statements out of context. I never stated that magnetic fields do not store energy, I stated that solenoids do not store energy in magnetic fields. A solenoid uses a magnetic field to produce linear motion; the energy of the magnetic field is converted to kinetic, not stored.

>>137486
I said solenoid, not inductor. A solenoid is just a load like a motor. There's no storage of energy in a magnetic field, it goes into pushing a big ferrite core forwards.

>>137479
There was nothing wrong with my statement. For clarification:

current [from the battery] slowly builds up in the capacitor, [we call stored current charge, Current = charge / time] .

I didn't mean to suggest there was current running across the capacitor.

>>137451 Once it's at full capacity it will release all of it's charge in one big surge.


>>137458 once a capacitor reached peak charge, it discharges.


What you both have wrong is you think a capacitor will AUTOMATICALLY discharge once it has reached capacity. A capacitor can be discharged once at full charge (or any other) , and it will do so very quickly, but its not something that happens on its own.

I've drawn a simple circuit of a capacitor used to boost the power of a solenoid. The power supply can't supply that much current all at once. When the switch is open that current slowly builds up in the capacitor. When the switch is closed the capacitor dumps everything its stored into the solenoid.

There are circuits which will make capacitors automatically discharge when near capacity, they usually rely on a zener diode divider triggering a complimentary transistor pair.

>>136376
No, cast it out of copper and watch parts of it go statue of liberty as you piss on them.

The flower garden part is still good though.

It looks like a switchblade stuck inside the soul. Try googling how switchblades work. Cobblers can build up the soul if you need more space to hollow out for it.

>>136308
Obligatory:

http://www.youtube.com/watch?feature=player_embedded&v=75WFTHpOw8Y#t=54s

>>135385
I went into university thinking I'd spend all day in an electronics lab getting my hands dirty. That's really where I excel, so it was a big problem when the program turned out to be 90% studying out of a textbook and solving problems on paper. There was also a huge clusterfuck of advanced calculus, which I hesitate to call useless, but for all the time and effort I put into it really hasn't payed off in any practical way.

Real world engineering jobs are closer to what I expected from university. The problems require a degree of creativity and detailed thought; not just having memorized a textbook.

Electronics engineer here. I was supporting myself while DIYing by helping designers and artists with their electronic ideas. LEDs, lasers, animatronics, etc. I did that for two years; but stopped recently because the pay was shitty and I got no recognition.

Now I've got a real 9-5 job designing control equipment for solar power plants. Its not that enjoyable, but its paying enough for me to get a studio, CNC machine, welding gear, etc. The plan is to develop my own electronic art projects; then get famous and quit my day job.

You can use a connector like that to go from a VGA source to composite video. You can't use it in reverse to produce a VGA signal from a composite source. A VGA monitor requires HSync and Vsync inputs.

>>132711
Sorry wrong pic.

>>132676
AC into a DC solenoid will just cause it to vibrate.

Increasing your voltage through a transformer or buck booster will decrease the current. It won't supply any extra power to the solenoid. The only time you'd want to do this is if you're using a thin wire solenoid that needs high voltage low current to not burn up.

To increase the power to the solenoid add a capacitor across the battery as shown. It won't increase the power continuously, but it will supply a kick when the switch is closed. The cap charges up from the battery when the switch is open then quickly dumps its stored power into the solenoid when the switch is closed.

There's a name for a circuit like this: "analog delay line". If you run the output of a delay line back into the input with some attenuation you'll get what sounds like an echo. The sound will repeat several times times quieter each repeat.

>>132419 What are you doing tonight, /diy/?
Tonight's project, sticking a bunch of LEDs in a colander and programming them to scroll math equations. Tomorrow's project is wearing it on my head to a Doctor Who themed dance rave.

My Halloween costume from a few years ago. I traced an outline of myself and measured so it would be the right size. I put the scrap metal together by bending some of the edges at 90 degree angles and bolting.

>>131667 It's quite easy to flash
OK, but how easy is it to download it's rom? Quite a few devices have lockouts against that sort of thing.

Pull the hex file out of it; that will give you the machine code. Humans can't read machine code at all. What you want to do is run a disassembler for whatever processor the code was meant for. Then you'll have some assembly language. Assembly is no cakewalk to read, but a move instruction will at least be "MOV,A,$172" instead of "F529".

Read the assembly, figure out what's going on, modify it, run an assembler, flash in your new hex.

>I dont want to go buy all the stuff and then figure out that none of it will work.
I see nothing impossible with your idea.

>>photocell lazer switch type thingy
We call it a photogate

Using seven servos seems like overkill to me. There are plenty of ways to dump some food once per day which only use one motor; such as food on a conveyer belt; an auger; etc.

The input would be the signals going into the base of those mosfets. Its a stereo amp, so there are two of them. For whatever reason somebody drew symbols that look like GND on them.

Mount an angel food cake pan on a lazy susan.

>>130587 12 V batteries
You talking a 12v car battery or a 12v watch battery?

We measure battery capacity in Amp-Hours, where one-amp hour is the ability to supply one amp of current continuously for an hour. When you put batteries in parallel you add up the amp-hours.

An efficient LED reading light will draw maybe 0.1 amps. So running it for 500 hours (three weeks) will require 50 amp hours. Figure out how many amps your appliances draw (should be printed on them) and do the math.

You also need to take into account the fact that batteries lose their charge over time even when not powering anything. Manufacturers should supply a graph on their websites. Deep Cycle batteries are designed to hold a charge as long as possible.

>>129336
Cheap transformers don't use a solid ferrite core, instead its some pieces glued together. When the glue wears down eddy currents can make the chunks of ferrite vibrate against each other. This shouldn't be dangerous, but it will reduce the maximum current it can provide.

I happen to be an expert in this area. Until very recently I was designing custom concert lighting equipment professionally with this company http://uvilab.com/

What I developed was a set of lights which accept DMX data through Ethernet using the Artnet protocol. Professional LJs (Light Jockeys) use a program called Madrix for controlling their lights through an ethernet network.

You can just use DMX instead of Artnet, but then you can't use standard computer networking gear to control your shit.

For an even simpler system you run sound into a microcontroller's ADC and use that to control lights standalone.

>>129344
Within the thermostat there will be a temperature sensor circuit which is a thermistor (temperature dependent resistor) combined with a regular resistor to make a voltage divider. The microcontroller uses the ratio of thermistor resistance to resistor resistance to determine what temperature the room is at and regulate the temperature.

What you want to do is replace the resistor with a smaller one; or just put another resistor in parallel with it. This will give the microcontroller false temperature readings that make the room appear hotter than it really is; so it won't activate the furnace until the room is at a much lower temperature.