Electrical Engineering V3 - Developers

:shock: NO you don't charge a LiPo like that unless you want it to explode and burn your house down, you need to use a proper charge IC. And a 5V boost converter.

[QUOTE=Chryseus;48341052]:shock: NO you don't charge a LiPo like that unless you want it to explode and burn your house down, you need to use a proper charge IC. And a 5V boost converter.[/QUOTE] He does not want to charge the battery, he wants to charge the phone WITH the battery. [editline]31st July 2015[/editline] USB chargers work at 5V, so yes, you have to increase the voltage.

ok, I'll get a step-up booster of 5v for the micro-usb output. and what is the proper way to charge that 3.7v battery with a USB-charger?

I suggest building a simply booster like [URL="https://learn.adafruit.com/minty-boost"]Minty Boost[/URL], simple and easy. As for charging, use a intelligent charge controller like the [URL="http://www.ti.com/lit/ds/symlink/bq24230.pdf"]BQ2423x[/URL] (See the application circuit in the datasheet) or a fully assembled charge module like [URL="http://www.adafruit.com/products/390"]Adafruit's USB/DC/Solar Li-Ion charger[/URL].

[QUOTE=Lyoko2;48341186]ok, I'll get a step-up booster of 5v for the micro-usb output. and what is the proper way to charge that 3.7v battery with a USB-charger?[/QUOTE] Do you have more info on the battery ? You'd use something like this: [url]http://www.linear.com/product/LTC4160[/url] [QUOTE=LoneWolf_Recon;48341226]As for charging, use a intelligent charge controller like the [URL="http://www.ti.com/lit/ds/symlink/bq24230.pdf"]BQ2423x[/URL] (See the application circuit in the datasheet) or a fully assembled charge module like [URL="http://www.adafruit.com/products/390"]Adafruit's USB/DC/Solar Li-Ion charger[/URL].[/QUOTE] That doesn't seem to support charging a LiPo.

[QUOTE=cartman300;48341087]He does not want to charge the battery, he wants to charge the phone WITH the battery. [editline]31st July 2015[/editline] USB chargers work at 5V, so yes, you have to increase the voltage.[/QUOTE] "USB host for recharging" Sounds like he does want to charge the battery too.

[QUOTE=Chryseus;48341232]Do you have more info on the battery ? You'd use something like this: [url]http://www.linear.com/product/LTC4160[/url] That doesn't seem to support charging a LiPo.[/QUOTE] [URL="http://www.helifreak.com/showthread.php?t=432982"]LiPos & Li-Ions use the same charge algorithm[/URL].

Do not build an actual circuit until you've watched a few LiPo fire videos on YouTube, so you understand what you're working with. Then you need to read up on safe LiPo charging, undervoltage protection, overvoltage protection, and polyfuses.

[QUOTE=nikomo;48341470]Do not build an actual circuit until you've watched a few LiPo fire videos on YouTube, so you understand what you're working with. Then you need to read up on safe LiPo charging, undervoltage protection, overvoltage protection, and polyfuses.[/QUOTE] Agreed, maybe we should tag battery charging in the same realm as working with AC. "Don't do it as a beginner"

[QUOTE=LoneWolf_Recon;48341497]Agreed, maybe we should tag battery charging in the same realm as working with AC. "Don't do it as a beginner"[/QUOTE] Lead acid batteries are fairly forgiving, given that they're only used in a well vented area. Oxyhydrogen gasses and such.

Just had a look at the status history for my PCB order from Elecrow. I sent it and paid on 31st, someone checked the gerbers and sent it to the boardhouse on the same day. If the boardhouse isn't too busy, and the postal system hauls ass, I can get boards pretty fast at a decent price.

Hello! Where can I get very cheap and quality LED stripes (that don't die quickly?) I need some of it for cheap. I live in Europe fyi.

ON Semiconductor datasheets give me cancer. So bloody ugly.

[QUOTE=LoneWolf_Recon;48341497]Agreed, maybe we should tag battery charging in the same realm as working with AC. "Don't do it as a beginner"[/QUOTE] Looks like the cell has a protection circuit in that blue tape (assuming it's the same), pretty sure you'd have to try quite hard for that to be dangerous...

[QUOTE=ben1066;48361523]Looks like the cell has a protection circuit in that blue tape (assuming it's the same), pretty sure you'd have to try quite hard for that to be dangerous...[/QUOTE] Sounds like a cell balancing circuit.

Got to play with something today :fap:. [thumb]http://i.imgur.com/cu6p5eU.jpg[/thumb] [thumb]http://i.imgur.com/W2yKTvC.jpg[/thumb]

Best thing about akiba so far: [t]http://www.lavandeira.net/wp-content/uploads/2015/01/chip_vending_machines_akihabara.jpg[/t] The idea is brilliant.

That's amazing. Did you buy any chips from them and could you record a video of them?

[QUOTE=pentium;48365820]Best thing about akiba so far: [t]http://www.lavandeira.net/wp-content/uploads/2015/01/chip_vending_machines_akihabara.jpg[/t] The idea is brilliant.[/QUOTE] And this is how you pick up your chip you want to: [IMG]https://upload.wikimedia.org/wikipedia/commons/2/2d/A_Claw_Crane_game_machine_containing_unicorn_plushes_in_Trouville,_France,_Sept_2011.jpg[/IMG] [sp]What are the prices by the way? [/sp]

¥400 is ~3.22USD A bit on the expensive side for age-old Z80's and seriously old Yamaha DACs, but not that bad if you just made a Z80 explode and need a replacement right this second.

[QUOTE=papkee;48367415]That's amazing. Did you buy any chips from them and could you record a video of them?[/QUOTE] I didn't bring a camera that does video but I bought a few of the Yamaha capsules because I got someone who's betting on an OPL chip or two.

hey guys can I connect loudspeaker scrambled out of smartphone directly to raspberry pi audio output? I'd also add ceramic capacitor between.

[QUOTE=Fourier;48415592]hey guys can I connect loudspeaker scrambled out of smartphone directly to raspberry pi audio output? I'd also add ceramic capacitor between.[/QUOTE] Yes, a cap isn't needed, you'd not use a ceramic anyway since the impedance would be too high at audio frequencies, you'd use a large electrolytic.

I tried it, the volume sucks. I saw it's line level so it's really only a shitty signal. Gotta fix the words - shitty = weak :v: [editline]9th August 2015[/editline] I have some MOSFETs lying around, IRF-540 something like that. What is the cheapest circuit with which I can drive LEDs from Raspberry PI? I will drive it with PWM.

[QUOTE=Fourier;48416003]I tried it, the volume sucks. I saw it's line level so it's really only a shitty signal. Gotta fix the words - shitty = weak :v: [editline]9th August 2015[/editline] I have some MOSFETs lying around, IRF-540 something like that. What is the cheapest circuit with which I can drive LEDs from Raspberry PI? I will drive it with PWM.[/QUOTE] Depending on how fast your PWM needs to be, you could feed the Pi output straight into the gate of a low-side mosfet. The gate capacitance shouldn't be too big of an issue if the PWM switching speed is only ~100hz.

[QUOTE=Dolton;48418394]Depending on how fast your PWM needs to be, you could feed the Pi output straight into the gate of a low-side mosfet. The gate capacitance shouldn't be too big of an issue if the PWM switching speed is only ~100hz.[/QUOTE] Or he could use ULN2003/2004 Darlington arrays, they come with up to 6 Darlington pairs in a single DIP package and they're easy to find in old junk as well.

With the inclusion of atleast a 10kOhm resistor going from each GPIO of the Pi to each darlington base. I've had luck with common 2N7000 mosfets for moderate current LED PWM.

I need to drive one big LED strip, 12V, 100Watt (7 meters long LED strip). 100Hz is a bad, I'd notice flickering. 200Hz, is that plausible? Hmm, I will go with this circuit [IMG]http://i.stack.imgur.com/5sKPR.png[/IMG] Power efficiency is not such a problem, since It will be running only about 30 minutes a day.

[QUOTE=Fourier;48422778]I need to drive one big LED strip, 12V, 100Watt (7 meters long LED strip). 100Hz is a bad, I'd notice flickering. 200Hz, is that plausible? Hmm, I will go with this circuit [IMG]http://i.stack.imgur.com/5sKPR.png[/IMG] Power efficiency is not such a problem, since It will be running only about 30 minutes a day.[/QUOTE] Err your power source is the wrong way around. I'm not sure what your doing with that 10 ohm resistor, current limiting ?, in which case it's way too large, for 100W 12V a 0.078 ohm 10W resistor would be appropriate if a bit crude. I'd reduce the gate resistor to 1k to reduce switching loss.

I copy pasted this picture from the internet. Power supply is wrong yes. Maybe that R2 10 Ohm resistor needs to go to base of Q1 instead? Thanks for the tips