Electrical Engineering V3 - Developers

[QUOTE=false prophet;48642769]What has changed in LEDs over the last 5 years that made them valuable in growing veggies/plants? I want to buy several dozen 5 watt LEDs of various wavelengths off ebay to use as a light source. But I got to thinking, what is difference between these and the 5w LEDs of yesteryear? Also, if I run an LED on a DC current, what will the flicker rate normally be? I want to experiment and see if flicker rate will have any effect on a plants growth.[/QUOTE] If you power it from true DC, it won't flicker at all. DC means that it's a constant voltage all the time. Of course such a thing as true DC can't be achieved. So, depending on the type of PSU you have, you can either have rather substantial 100Hz/120HZ (EU/US) flickering with linear supplies, or barely any flickering in the kHz- to MHz-area with a switchmode supply. If there would be any noticable flicker, it would come from a linear supply, but you're unlikely to use one since switchmode supplies are way cheaper these days. (Not to mention that a well engineered linear supply will hardly flicker at all anyway). At any rate there won't be any flickering that you can actually notice, unless you use a really underspecced or shitty supply.

[QUOTE=false prophet;48642769]What has changed in LEDs over the last 5 years that made them valuable in growing veggies/plants? I want to buy several dozen 5 watt LEDs of various wavelengths off ebay to use as a light source. But I got to thinking, what is difference between these and the 5w LEDs of yesteryear?[/QUOTE] Modern LEDs are much brighter, many exceed 100lm per watt so 5W can give you over 1000lm. For a grow lamp you need at least red and blue LEDs, with around double the number of blue LEDs since they are less efficient than red.

[QUOTE=Chryseus;48645197]Modern LEDs are much brighter, many exceed 100lm per watt so 5W can give you over 1000lm. For a grow lamp you need at least red and blue LEDs, with around double the number of blue LEDs since they are less efficient than red.[/QUOTE] Also just buying the first and best LED's ain't good, you gotta find some data on what specific wavelengths your plants wants, and then buy LED's which outputs primarily that wavelength.

[QUOTE=Van-man;48645710]Also just buying the first and best LED's ain't good, you gotta find some data on what specific wavelengths your plants wants, and then buy LED's which outputs primarily that wavelength.[/QUOTE] HOW TO: Energy efficiently grow weed in your basement!

[QUOTE=nuttyboffin;48646196]HOW TO: Energy efficiently grow weed in your basement![/QUOTE] There's already complete kits with specialized LED growth lamps and stuff, pretty cool.

I've already researched the wavelengths I want to target. I'm just curious about the questions I've asked.

We all know the best wavelength is 420nm

[QUOTE=Chryseus;48648604]We all know the best wavelength is 420nm[/QUOTE] [URL="http://ledgrowlights.theperfectgrow.com/intorduction-to-led-grow-lights/"]You're not wrong[/URL]: [IMG]http://ledgrowlights.theperfectgrow.com/wp-content/uploads/2015/02/Grow-Absorbtion-Peaks.jpg[/IMG] Electrical Engineering v. Hydroponics Control Systems For The Dank Kush

It's for strawberries and peppers! :( Specifically these strawberries: [url]http://i.imgur.com/kFKDfrx.png[/url] An alpine variant that I am trying to grow to maximum size and breed my own larger sizes from! [edit] there are 6 peak wavelengths that I will target. Unfortunately due to the nature of LEDs, it won't be feasible to assume each LED will output that exact wavelength. So each panel will have 20 5w LEDs and I will build 2 panels. [edit2] for anyone wondering how I got my alpine strawberries larger than a fat ass thumb: pee pee.

the wavelengths there are pretty logical, just looking at a plant you see green, therefore you know the plant does not absorb or use much green light (as it gets reflected off) So logically it's gonna be Red & Blue! :D

Man did I fuck up today. Got an old motorola brick of a radio and tried to fix the problem it was having with TX power. Fixed it and it worked perfectly, but somehow I damaged the ribbon cable or connector to the front panel, so now none of the buttons, mic, speaker, or display works. Plus I think I messed it up even more by trying to fix it. When I first noticed the problem the speaker and mic still worked. :suicide: So that's $40 I'm not getting back. I like electronics.

Got an old "Com-trol' unit from work. Dusty as all get-out, but it contains a Z80 CPU, an Altera FGPA of some sort, a couple of EPROMs, and 17 or so 128Kx8-bit CMOS SRAM chips in 32-pin DIP packages. :excited: Oh man, this thing is full of neat stuff, including a modem card (and the connector is thru-hole and could be re-used or put on a breadboard with some modifications), a non-volatile memory controller, a couple of dual 232 transceivers (MAX233s), and a SCN2681AC1N28 DUART.

Some guys at the company I work at realized they used a wrong MOSFET on the power distribution board of their custom drone, which was the only model working at the time. Said board had gone trough testing fine, and even had been used in test flights. The MOSFET had been used at over twice the rated load :v:, they called the factory but they dunno how that worked either.

Woopsie, it happens

[QUOTE=scratch (nl);48650475]Some guys at the company I work at realized they used a wrong MOSFET on the power distribution board of they custom drone, which was the only model working at the time. Said board had gone trough testing fine, and even had been used in test flights. The MOSFET had been used at over twice the rated load :v:, they called the factory but they dunno how that worked either.[/QUOTE] So an effective deadbug fix for those drones already made :v: [URL="http://www.irf.com/technical-info/appnotes/para.pdf"]Just stack[/URL] [URL="http://robotroom.com/Thermal-PCB-Motor-Driver-Tests-3.html#STACK"]another on top![/URL] (Unless it has no exposed leads, [URL="https://www.youtube.com/watch?v=bLMYTQUw8Lc"]its a legitimate strategy[/URL])

[url]http://www.electrical-workbench.co.uk/2015/09/der-ee-de-5000-lcr-meter-review.html[/url] Here's a quick review of the Der EE DE-5000 LCR meter.

[QUOTE=Chryseus;48652858][url]http://www.electrical-workbench.co.uk/2015/09/der-ee-de-5000-lcr-meter-review.html[/url] Here's a quick review of the Der EE DE-5000 LCR meter.[/QUOTE] Bullet points, use them.

[QUOTE=DrDevil;48653373]Bullet points, use them.[/QUOTE] Added more just for you.

Im working on a portable 2x 50W amplifier with battery and bluetooth 4.0 But after i finished it, it didnt worked.. i tought i broke it but the problem was that the battery had 28.8Volts, which the amp didnt like. so i applied 20V from a powersupply and it worked. now i need a step-down converter. Reworking the battery would be too expensive, because i would need a new charger [url=http://www.directupload.net/file/d/4106/f3snsc8s_jpg.htm][img]http://fs2.directupload.net/images/150910/temp/f3snsc8s.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/4hfo295n_jpg.htm][img]http://fs2.directupload.net/images/150910/temp/4hfo295n.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/58n5sakj_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/58n5sakj.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/oiyxqcrj_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/oiyxqcrj.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/4mvtsaz5_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/4mvtsaz5.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/rwt8jwel_jpg.htm][img]http://fs2.directupload.net/images/150910/temp/rwt8jwel.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/gxeveme2_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/gxeveme2.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/diqbrgtm_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/diqbrgtm.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/6njkw9mf_jpg.htm][img]http://fs2.directupload.net/images/150910/temp/6njkw9mf.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/a48gb3et_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/a48gb3et.jpg[/img][/url] [url=http://www.directupload.net/file/d/4106/6mgjzfvc_jpg.htm][img]http://fs1.directupload.net/images/150910/temp/6mgjzfvc.jpg[/img][/url]

[QUOTE=gamerpaddy;48654435]Im working on a portable 2x 50W amplifier with battery and bluetooth 4.0 But after i finished it, it didnt worked.. i tought i broke it but the problem was that the battery had 28.8Volts, which the amp didnt like. so i applied 20V from a powersupply and it worked. now i need a step-down converter. Reworking the battery would be too expensive, because i would need a new charger [/QUOTE] Step down converter or as I like to call it, a resistor. Efficiency is for commies. Just kidding don't listen to me I hate and love electronics at the same time. Neat project though, whats the battery life like? And why is everything in electronics so seemingly complicated? I've been designing a little power supply and came across what seems to be a common design, as show below. I just wanted to see how other people did this compared to what I came up with. [img]http://i.imgur.com/qSamwt6l.png[/img] Seems straight forward..ish. But then I was wondering how you choose R1. And then I was wondering how the output voltage is related to the setting of the potentiometer. After a little bit I came up with the equation: [img]http://i.imgur.com/DjPcKzcl.png[/img] Assuming R2 and R3 are the potentiometer. I mean, it appears to be a relatively basic circuit but then you have this big dirty beta-dependent equation determining the output voltage. When it comes to bigger circuits like discrete amplifiers I pretty much lose it completely. I can visualize the general blocks and follow the audio signal but I can't really formally analyze it. There's too much going on for me to comprehend it.

well, i cant really measure it, since music isnt playing all the time on 100% power. i think, its 3 to 4 hours, like my previous one, which had the same battery and speakers but a 2x 100W class d amp. i ran it for like 6 hours on 25% volume. Still had 24.4V on battery which is 3.48 of 3.8V per cell. some values: 7x 2.6Ah Samsung ICR18650 26F cells 15A 7 cell BMS (bit high, but there wasnt a cheaper one) 2x 50W bluetooth 4.0 amplifier Magnat monitor 110 speakers for testing / mobile use XLR socket for charging using a e-bike 2Amp charger. This is compatible with my old speakers, so i can power them using the battery of the new one. damn lot of hot glue, hopefully i can take this somehow apart when it breaks. Oh and i forgot the fuse. if a wire break and shorts the lithium batterys, i throw it out of the window. so it can safely explode. Progress: now ive put in a step down converter i had laying around... i think it need some capacitors or a stronger step-down unit. when heavy bass is playing, it cracks, like theres not power left. With the step-down in a cardboard enclosure, it got twice the size, with plenty of unused room. Maybe i add a USB charger, since this is made for smartphones. Screw-terminals i also need.. bare wires flapping around isnt that great.

[thumb]http://i.imgur.com/bDfOcFi.jpg[/thumb] Heh, the transistors arrived faster than i thought.

My Aunt has a kid with down-syndrome that keeps escaping down stairs to watch frozen at midnight... She wants an alarm so she gets woken up when the kid leaves their room. ... would this do? [url]http://www.ebay.co.uk/itm/White-Shop-Door-Bell-Visitor-Entry-Alert-Door-IR-Motion-Sensor-Welcome-Bell-/181820387979?hash=item2a5556f28b[/url]

I'd personally use a magnetic door switch, a bell and a 12 AC adapter. [img]http://4.bp.blogspot.com/_kl-7x84Cuu8/SxCWD-kOcHI/AAAAAAAABEk/rf32Mu9og68/s1600/electric-bell-thumb4031121.jpg[/img] Make it sound like a prison break every time he tries to escape.

[QUOTE=nuttyboffin;48674286]My Aunt has a kid with down-syndrome that keeps escaping down stairs to watch frozen at midnight... She wants an alarm so she gets woken up when the kid leaves their room. ... would this do? [url]http://www.ebay.co.uk/itm/White-Shop-Door-Bell-Visitor-Entry-Alert-Door-IR-Motion-Sensor-Welcome-Bell-/181820387979?hash=item2a5556f28b[/url][/QUOTE] Reed switch and magnet stuck ontop of the door? [t]http://s22.postimg.org/tseewmzht/08_reed_switch_loca.jpg[/t] it's atleast gonna be a surefire way of telling whenever the door's been opened

I think the door has to be left open. Originally she wanted a laser, however I told her that would easily beat her £30 budget.

[QUOTE=nuttyboffin;48674286]My Aunt has a kid with down-syndrome that keeps escaping down stairs to watch frozen at midnight... She wants an alarm so she gets woken up when the kid leaves their room. ... would this do? [url]http://www.ebay.co.uk/itm/White-Shop-Door-Bell-Visitor-Entry-Alert-Door-IR-Motion-Sensor-Welcome-Bell-/181820387979?hash=item2a5556f28b[/url][/QUOTE] It should, yeah.

I can't make heads or tails out of the H11A1 optocoupler datasheet. Could i toggle about 15V with it to supply the voltage to a MOSFET gate?

[QUOTE=cartman300;48680001]I can't make heads or tails out of the H11A1 optocoupler datasheet. Could i toggle about 15V with it to supply the voltage to a MOSFET gate?[/QUOTE] [img]http://i.imgur.com/60M4JC4.png[/img] Use a general purpose NPN transistor, I.E 2N3904.

[QUOTE=Chryseus;48680599][img]http://i.imgur.com/60M4JC4.png[/img] Use a general purpose NPN transistor, I.E 2N3904.[/QUOTE] I don't have one. But i do have a surplus of H11A1's :v: