Electrical Engineering V3 - Developers

I figured I'd make something temporary whilst I think about power supply design. [t]https://i.imgur.com/ArXO8Kx.jpg[/t] 19V ASUS netbook charger, to boost converter with 27-30V output, to buck converter that gives me whatever I need. No current limiting. Totes safe. I never make mistakes, until I do, so it's OK. I'm happy that I don't have a scope to throw that at, the output is probably so dirty. Also, the Nest products are electronically really easy, any special sauce is in the programming. The hard part is getting it certified for consumer sale.

[QUOTE=nikomo;47833184]I figured I'd make something temporary whilst I think about power supply design. [t]https://i.imgur.com/ArXO8Kx.jpg[/t] 19V ASUS netbook charger, to boost converter with 27-30V output, to buck converter that gives me whatever I need. No current limiting. Totes safe. I never make mistakes, until I do, so it's OK. I'm happy that I don't have a scope to throw that at, the output is probably so dirty. Also, the Nest products are electronically really easy, any special sauce is in the programming. The hard part is getting it certified for consumer sale.[/QUOTE] Ebay/DX/Aliexpress buck-boost converters are literally just what you did, except on one PCB. I'm no electronic engineer, but that alone has me concerned, since two switching regulators can easily interfere with each other. It's like the people not caring about patents hasn't managed to copy a SEPIC IC yet.

[QUOTE=Chryseus;47831855]Picking up a microcontroller development kit like an Arduino would be the best place to start as well as learning the basics of electronics with a breadboard and some components, if you want to make a finished product in the future you'd also need to spend some time learning how to design and layout a PCB. I also added a bunch of new free books to the op.[/QUOTE] Yes, books are important. There are also a metric butt-ton of videos and other such freely available tutorials online, but it'd be best to start with some of the basics. AfroTechMods' Youtube channel has a good deal of videos explaining basic principles and components.

I know the high-frequency component of switching goes right through linear regs, which causes the output to be a bit dirty, but I'm not sure how bad it can be with switch to switch to switch. That's why a scope would be nice, but school's over for now, so I don't have access.

He can create a high current [URL="http://sim.okawa-denshi.jp/en/RLClowkeisan.htm"]LC low pass filter[/URL] to remove the high frequency components and reduce ripple.

My inductor options are a bit limited here. I'll figure out some load for it, and let it go for a while, and see if it manages to go out of regulation, I don't care much since it's just temporary, and I honestly don't need much more than the 5V rail from USB with the stuff I'm doing.

Just programmed my first attiny85. :dance:

[QUOTE=Leestons;47834566]Just programmed my first attiny85. :dance:[/QUOTE] Welcome to the league of AVRs brother! Provide pics/video.

[QUOTE=LoneWolf_Recon;47834736]Welcome to the league of AVRs brother! Provide pics/video.[/QUOTE] Thanks! Just a blinking LED at the moment so not much to take a photo of. Maybe when I do something more interesting with it.

[QUOTE=Leestons;47834566]Just programmed my first attiny85. :dance:[/QUOTE] At least you didn't struggle for a week because the ATtiny84 library you got off the arduino website had all the pins misassigned :v:

I feel so fucking dirty repairing this PCB. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9284.jpg[/IMG] The PCB is paper thin, the traces are amazingly flimsy and just picking at them with a fingernail pops them off. If that isn't annoying enough it's fucking single sided [i]with all pads and traces on the topside, under the components[/i] so when you go to solder everything in you really can't make a good joint betweeen pins and pads, so there's a lot of reworks you have to add because well, it's shit. :v:. I felt like I was better off just taking a piece of perfboard and starting over. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9290.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_9292.jpg[/IMG] I don't know who the fuck originally designed this board, but I hate them.

Jesus and I thought I was having a hard time with soldering.

[QUOTE=Cakebatyr;47836461]At least you didn't struggle for a week because the ATtiny84 library you got off the arduino website had all the pins misassigned :v:[/QUOTE] That threw me off a little at first. I thought I had programmed it wrong because the LED wasn't blinking. I had forgotten that the physical pin isn't necessarily the same as the pin defined in software. About ten minutes later I had it all worked out.

How clean/reliable do you guys think [URL="http://www.ebay.com/itm/Universal-DC-12V-1A-30A-Switch-Switching-Power-Supply-Driver-For-LED-Strip-/221634474416"]these things[/URL] are? I'm looking for something to power all of my networking devices which all conveniently run on 12v.

[QUOTE=papkee;47845451]How clean/reliable do you guys think [URL="http://www.ebay.com/itm/Universal-DC-12V-1A-30A-Switch-Switching-Power-Supply-Driver-For-LED-Strip-/221634474416"]these things[/URL] are? I'm looking for something to power all of my networking devices which all conveniently run on 12v.[/QUOTE] I've purchased some of these in the past and while they're not entirely terrible I would never trust one of these for anything that requires uptime/stability. I use some of them to run LED lighting in my apartment and for some other hobby projects. Unless it's for personal hobby use, get something with an actual brand name on it.

[QUOTE=papkee;47845451]How clean/reliable do you guys think [URL="http://www.ebay.com/itm/Universal-DC-12V-1A-30A-Switch-Switching-Power-Supply-Driver-For-LED-Strip-/221634474416"]these things[/URL] are? I'm looking for something to power all of my networking devices which all conveniently run on 12v.[/QUOTE] If you are getting a power supply that you want to run 24/7 and don't want a fire, don't get a cheap power supply. Those things are built down to the lowest possible quality possible and the things the cheap out the most on are the safety components. Get a Meanwell / TDK Lambda / whatever as long as it's any real brand.

[QUOTE=ddrl46;47845647]If you are getting a power supply that you want to run 24/7 and don't want a fire, don't get a cheap power supply. Those things are built down to the lowest possible quality possible and the things the cheap out the most on are the safety components. Get a Meanwell / TDK Lambda / whatever as long as it's any real brand.[/QUOTE] Got a 36V one from Cheapistan for my CNC table. :worry:

[QUOTE=Zero-Point;47845672]Got a 36V one from Cheapistan for my CNC table. :worry:[/QUOTE] Well I assume you are around when you are using that thing so if shit hits the fan you are able to turn it off I guess. Also, finally got a sweep generator woop :v:. [url=http://i.imgur.com/fKtvvSB.jpg][img]http://i.imgur.com/fKtvvSBl.jpg[/img][/url]

That plugin is worth more than your family put together.

[QUOTE=papkee;47845451]How clean/reliable do you guys think [URL="http://www.ebay.com/itm/Universal-DC-12V-1A-30A-Switch-Switching-Power-Supply-Driver-For-LED-Strip-/221634474416"]these things[/URL] are? I'm looking for something to power all of my networking devices which all conveniently run on 12v.[/QUOTE] What networking devices run on 12V? How many amps do you need? Can you get away with 13.8V? If so you might want to get a [URL=http://pages.ebay.com/link/?nav=item.view&id=151682660677&alt=web]used Astron SMPS[/URL] off eBay. They are designed with fairly heavy noise filtering and prolonged on-time in mind for powering commercial and EMCOMM radios.

[QUOTE=Cakebatyr;47846319]What networking devices run on 12V? How many amps do you need? Can you get away with 13.8V? If so you might want to get a [URL=http://pages.ebay.com/link/?nav=item.view&id=151682660677&alt=web]used Astron SMPS[/URL] off eBay. They are designed with fairly heavy noise filtering and prolonged on-time in mind for powering commercial and EMCOMM radios.[/QUOTE] Most networking equipment have a internal switchmode power supply that steps the 12v down to a more usable voltage. The 12v plug is just so they can get away with a wall wart for every specific type of AC plug and voltage, instead of a complete device for each. BUT there's only one way to find out, and that is to crack open the networking equipment and check. Or see if that power supply you linked can be easily modified so it outputs 12volt instead of 13.8 volt. If lucky, then it's a high precision multi-turn potmeter that's used to fine calibrate it, and if not, then two resistor that's easy to unsolder and replace, so the feedback to the switchmode part makes it output 12volt.

[QUOTE=Van-man;47846560]Most networking equipment have a internal switchmode power supply that steps the 12v down to a more usable voltage. The 12v plug is just so they can get away with a wall wart for every specific type of AC plug and voltage, instead of a complete device for each. BUT there's only one way to find out, and that is to crack open the networking equipment and check. Or see if that power supply you linked can be easily modified so it outputs 12volt instead of 13.8 volt. If lucky, then it's a high precision multi-turn potmeter that's used to fine calibrate it, and if not, then two resistor that's easy to unsolder and replace, so the feedback to the switchmode part makes it output 12volt.[/QUOTE] Ah, I'm so used to designing with 5V USB power I forgot about that...

[QUOTE=ddrl46;47845702]Well I assume you are around when you are using that thing so if shit hits the fan you are able to turn it off I guess. [/QUOTE] Other than the motors, it should be fine in terms of how loaded down it is so hopefully it won't go tits-up on me any time soon. But if it does, I'll remember to buy 'MERICAN.* *I tried that in the first place by selecting "North America Only" on eBay and wouldn't you know it, some cheap-ass retailing Cheapistani SMPS'...

So I just bought a motorcycle and I need to fix some things with the lighting, basically when I start gassing the light works just fine, but when I reach top speed, the lights in the motorcycle burst because there's too much current being delivered by the dynamo, how will I limit the current of the dynamo so it doesn't break my lightbulb? The bulbs in there are 6V and 2.4W, I don't think upping the watts will work because the bulbs need to fit inside my casing.

[QUOTE=Staneh;47847370]So I just bought a motorcycle and I need to fix some things with the lighting, basically when I start gassing the light works just fine, but when I reach top speed, the lights in the motorcycle burst because there's too much current being delivered by the dynamo, how will I limit the current of the dynamo so it doesn't break my lightbulb? The bulbs in there are 6V and 2.4W, I don't think upping the watts will work because the bulbs need to fit inside my casing.[/QUOTE] Does the dynamo/generator/alternator have any kind of built-in regulation? Otherwise you can do the trick that's done on older cars that tended to blow the headlight bulbs constantly, and put a ordinary but beefy rectifier diode in series with the bulb. There's a voltage drop of around 0.6 to 0.7 volt across such diode.

[QUOTE=Van-man;47847513]Does the dynamo/generator/alternator have any kind of built-in regulation? Otherwise you can do the trick that's done on older cars that tended to blow the headlight bulbs constantly, and put a ordinary but beefy rectifier diode in series with the bulb. There's a voltage drop of around 0.6 to 0.7 volt across such diode.[/QUOTE] It's a really old motorcycle from the 70's, so probably not, but thank you, I'll try that!

[QUOTE=papkee;47845451]How clean/reliable do you guys think [URL="http://www.ebay.com/itm/Universal-DC-12V-1A-30A-Switch-Switching-Power-Supply-Driver-For-LED-Strip-/221634474416"]these things[/URL] are? I'm looking for something to power all of my networking devices which all conveniently run on 12v.[/QUOTE] You can get those power supplies on local Chinese markets so new, they're only a few hours old. I have no idea who keeps buying so many of them, that they have to continuously produce new stock. You'd think they'd just do a massive batch of them, and then sell them gradually over time, but if they're constantly producing them, that means sales are matching production closely.

Here I made a short blog post which also includes PCB porn: [url]https://kobibok.wordpress.com/2015/06/02/wifi-rc-car-controlled-by-browser-based-app-from-pc-or-androidios-through-websockets/[/url] A single picture to lure you in :v: [IMG_thumb]https://kobibok.files.wordpress.com/2015/06/pcb_soldering_almost_complete.jpg[/IMG_thumb]

[QUOTE=Van-man;47847513]Does the dynamo/generator/alternator have any kind of built-in regulation? Otherwise you can do the trick that's done on older cars that tended to blow the headlight bulbs constantly, and put a ordinary but beefy rectifier diode in series with the bulb. There's a voltage drop of around 0.6 to 0.7 volt across such diode.[/QUOTE] My scooter just had a massive resistor that pulled down the lamp voltage. I left it unplugged once and blew every bulb in the scooter :v:

[QUOTE=MIPS;47867556]My scooter just had a massive resistor that pulled down the lamp voltage. I left it unplugged once and blew every bulb in the scooter :v:[/QUOTE] I've seen examples where it was a chunky zener diode & resistor bolted to a heatsink, one of them was on a made-in-China scooter. A slightly more refined approach of what you've seen.