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> I don't know, maybe that's its intended function, as I said, it works, but I'm a bit afraid that it will drain the four AA batteries pretty fast, and could possibly damage rechargable ones by too much current draw.
>
> Yes, I do have a multimeter. A sticker at the back rates the radio for 6V and 4w (as far as my understanding of russian goes)

4 watts is an enormous amount of power to draw from 4 modestly antique alkaline AA batteries in a receive-only radio. However, it's not too much, especially for rechargeable AA batteries. You just have to avoid fully discharging them to extend their life. You can do that by timing how long it takes to fully discharge, then cut that time in half, and charge your AA batteries at the halfway point. I'm guessing you will only get a few minutes of run time.

You will also need a smart charger that won't overcharge half-discharged AA batteries with a full charge. Might as well get good AA batteries too, because the best charger comes with them. I recommend you get these ones (make sure your battery specifications match the packaging in this photo):

• New battery day! 24 AA Eneloop NiMH batteries in 16 and 8 cell packs. : r/AAMasterRace
  
  Get this package first to get the highest quality charger on the market:
  
  
• AmazonSmile: Panasonic K-KJ17MCA4BA Advanced Individual Cell Battery Charger Pack with 4 AA eneloop 2100 Cycle Rechargeable Batteries: PANASONIC: Electronics
  
• HKJ Review of Charger Panasonic BQ-CC17 - lygte-info.dk
  
  > A nice -dv/dt termination with only a small temperature increase and no trickle charge, this looks very good. [...] The charger is very good at filling the batteries.
  
  You need that charger to get the full life out of Eneloops. If you take care of them, Eneloops will last at least a decade, maybe longer. They achieve maximum longevity when you charge before they reach 60% depth of discharge (40% remaining capacity). So, if you charge them at the half discharged point (50% remaining capacity), that's a convenient even number, and a bit better than the ideal.

WALL OF TEXT ALERT:

The most difficult part of building a proper charger for an 18650 bank will be to ensure that the charge system will be able to balance each battery/cell during charging. You can find a lot of single cell charging solutions at sparkfun. The only thing is that product is only meant to handle a single cell. You could run one of those charging boards for each cell but I could see that being pretty bulky.

You specified that you want the bank to be 12 V with a capacity of 50 Ah. The nominal voltage for an 18650 is 3.7 V but fully charged is 4.2 V. That would mean that you want 4 batteries in series to ensure > 12 V during use while they drain down to 3.7 V each before needing a recharge (This is assuming that your output regulator does not have a boost on it). To achieve the 50 Ah mark you will need a total of 17 batteries (or 16 for a capacity of 48 Ah if the 50 Ah is not a strict requirement). That would need that you need 4 sets in parallel of 4 batteries in series (If that makes sense). I would go for the 4 sets of 4 to keep the parallel sub-groups of the system symmetric and balanced during discharges. You will definitely need some regulation out of the battery bank for the devices you want to charge. Probably a 12 V out and a 5 V out for various devices. This also assumes that the batteries internal behaviors during discharge will let every set of batteries discharge all at the same rates, which will probably not perfectly be the case.

Like I said, the most difficult part of this build will be making the charging side be able to balance the cells during charge. It might be easier to just get a hold of a 4 cell 18650 balance charger, unplug the batteries from your system, and charge the batteries in a pre-made charging system. For the most optimal charge times you would want 4 of those chargers so you can charge each parallel group at the same time. Something like this.

I did find this charging PCB on EBay that could be built into your bank with the input pads all soldered in parallel for each sub-bank of batteries (Make sure the wiring can handle more than 12 A or bundle 4 sets of wires together that can handle 3 A each). The board is rated for a maximum current of 3 A meaning that to charge 4 batteries up to 3000 mAh (3 Ah) would take roughly 4 hours for each sub-group of cells. The big charger would definitely charge each set of batteries much quicker, but would be a separate system from your charger bank.

Keep in mind that everything I've discussed was just a quick breakdown of the difficult parts that I can see right now. I'm not 100% sure what kind of output rails you want to build or the currents you want to be able to run out of the bank. I tried to focus mainly on the charging portion of the project. Since LiPos need a proper charging system to keep the batteries healthy over long periods of use and each cell needs to be balanced for everything to remain in spec over the duration of the life of system any charging system needs to be able to perform proper balanced charging to each cell.

Let me know if you have any other questions or are looking for any particular out-of-box solution for any piece of the project. Something like this could be very useful to have, but you definitely want to make sure that the batteries will be properly handled to ensure longer lifetimes.

Oh wow, I have non-24 and not very much money, so I've actually been working on doing basically the same thing! Right now I have some fluorescent grow lights plugged into a wemo switch, and let me tell you..... it's certainly not the same.

The bad news is that from what I can find, there's no real good way to do it cleanly if you want dimming, since most smart plugs are a simple binary on/off. I have found a few options though!

(I'm sure you know but please note the requisite be super careful around AC voltage, it'll make you dead)

The first is something along the lines of this, what's meant to be an in-wall dimmer to replace a 1-gang light switch. That's probably gonna be the easiest way to do it -- just attach it to the wires in-line, and you're good to go. There are other, similar options that may be cheaper, especially if you can use something like z-wave.

I don't have a link atm, but I also know that I've seen someone take a normal cheapo wall dimmer and just... hook a lil servo motor up to it. That's also an option?

After some searching, I did find what seems to be the one plug-in smart dimming outlet that doesn't require a hub. Heads-up though, it's only rated to 100W with LEDs so you'll wanna be careful. Not having look much into this, I make no promises, but my cursory googling actually seems really promising. Price isn't horrible, either.

So here's where I thought to check the wonderful world of Sonoff. It's not the CLEANEST solution visually, but they actually do make a smart socket -- if you're willing to drop $60 and be done, just get six of these guys here.

EDIT: Just kidding, those bases also do not have dimmers, so they won't work. But here's a video of someone using one of their surprisingly cheap wall dimmers to do just what you want!

You'll want to connect them to each other like this.

You could solder them directly together, but I'd suggest using wires between them; solder one of the wire to one board, and the other side of the wire to the other board.

You could use electrical tape over the solder junctions to insulate them (instead of heat shrink), but make sure you wind the tape snugly and use at least 3 layers of tape around each junction. Here's an example kit of heat shrink. It's not expensive, and is rather easy to use. video of how to use shrink tube. Video on using a hair dryer in case you don't have a heat gun. If you don't have a heat gun or hair dryer, then heat shrink probably isn't a good option for you at this time.

For the capacitor and the wiring connections, don't follow the diagram verbatim. If one wire touches a bunch of other wires, it doesn't matter WHERE they touch, only THAT they touch. So, in theory, you could have one long "main" wire and solder other wires onto it separately one at a time along the entire length of the "main" wire, or you could just wire the ends of all the wires at one single spot, or "junction". Either way has the same effect - all the wires are ultimately touching. See how the capacitor is connected to the red and black wires? You could solder it at any point on either of those wires. So it could go right on top of the end of the neopixel strand, or right on top of the arduino, anywhere that you think would work well for how you're assembling this thing. If you're using a breadboard (i suggest this) and want the easiest option, you could plug it right into there and not worry having to actually solder it to anything. If you want a "best practices" opinion, it would be ideal to solder it right into the end of the neopixel strand.

Since you're using multiple neopixel strands, It might be best to use one of these capacitors in between each strand in a similar fashion. I'm not sure how much this would actually matter, though. Just kind of a safe vs sorry thing, I guess. One capacitor is probably fine.

By the way, on my diagram, I used pins 6 and 11 as examples. You can use any pin with an "A" (A0 thorugh A7) for the potentiometer, any PWM pin (3, 5, 6, 9, 10, or 11) for the neopixel output, and any pin with a "normal" number (2 through 13) for the pushbutton. Info on arduino pins.


More info on Arduino Pro pins, etc

This basic remote that comes with LED strips usually:

https://www.amazon.com/SUPERNIGHT-Changing-Flexible-Remote-Control/dp/B00BP4DUMU?ref_=fsclp_pl_dp_3

The battery is fine and it works but I realy want to be able to point it in different angles and still be able to use it because no I need to be 1m or closer and aim dirrectly to it and the reciever is in pretty uncomfortable spot so I have to walk there everytime and put my hand behind shelf to change colors. Maybe I can modify the remote and/or reciever to be able to do it from ~5m and in different angles too? I understand that I cant point the remote away and hope that it will work but cmon I can't be wrong by 0.5 degrees now if I want it to work now....

K I am bit oversaturating but I realy want to upgrade it a bit XD

Thanx

Arduino is great for plug and play, blink an LED, using code. But if you want to understand electronics I would start here:
Easy Electronics (Make: Handbook) https://www.amazon.com/dp/168045448X/
^you could shoot through this book in a weekend.

After doing that book I would get this book:
Make: Electronics: Learning Through Discovery https://www.amazon.com/dp/1680450263/
You can purchase the parts individually or buy kits specifically made for the books. I found the kits will save you time.
I started like you a few years ago and now have moved on to arduino and am designing my own PCBs. Good luck.

I would drill holes in a stiff material to line them up to meet your designs specifications, and use something like a "metal test probe pin," or pogo pin, to align the legs individually. I use this method, and it helps me out quite effectively. Amazon link: https://www.amazon.com/Uxcell-a15091500ux0390-P75-E2-Convex-Diameter/dp/B018YPQ6ZK/ref=sr_1_5?ie=UTF8&qid=1543465361&sr=8-5&keywords=pogo+pins But anything small and cylindrical will do the job of moving the legs of the pot for your needs without compromising the legs enough to break on you. I hope this helps you; it works for me. Cheers

> I'm just wondering what would be the best method for the dc 2 dc conversion, I also want to ensure the circuit can handily cope with any sudden surges in demand, while maintaining a clean and stable 5v supply.

I like the laptop PSU idea. I do that in my projects sometimes.

You may want to consider having more PSU headroom to avoid running near max capacity for your 5V reg. I snooped around and found this item. It delivers 10A from 12-24 VDC. What I can't find is a decent set of specs to give the Power Out noise (ripple). I like my 5V ultra quiet.

Envy you the PI4 BTW. Would you please tell me your RAM size and performance browsing the web? My PI3-1GB barely makes it for web browsing.

hth

I'm using the 4GB and even with raspbian it fair zips along, I'm running with root on a usb ssd (careful not all usb3 -> sata are compatible) and that does make a difference, a 240 sdd can be cheaper than and expensive 32gb sd card and much faster... It certainly has enough power to browse the web the pi2 was torture by comparison! chromium loads in around 2-4 seconds, and feels just like its on a fairly standard laptop!

re: this Will this require some kind of heat sink, I'd prefer something as efficient as possible, I'm wondering if it might need a set of different valued capacitors on the output to help with ripple, I do have a modest oscilloscope so I should be able to see how horrid the ripple or takeup looks like I am wondering what would happen when there is sudden cpu load applied and the governor switches all 4 cores from 600hmz to 1.5ghz....!

I was a little dubious about the claims attached to the Pi4 but was pleasantly surprised, you could certainly use it as I've set mine up (root on ssd, etc), as a "daily driver"

You may be able to do something like this:

Use an RC/Drone LiPo battery: https://www.hobbyzone.com/batteries/lipo/4-cell/ONXP2459.html

Connect it to a switching Dc-Dc converter: https://www.amazon.com/dp/B06X1DPFQQ/

Now you have 5V, 30A available for your LEDs. Note, things will get HOT running at full power, you'll need a way to cool down the LEDs and the Dc-Dc converter.

Using that battery (75 watt hours), you should be able to power your LEDs (150watts) for about half an hour at full brightness.

Also, Id be very careful working with high capacity Lipo batteries, do your research and take precautions, they can be dangerous if not used correctly (shorting out leads/puncturing the case etc).

You may be able to find a better quality Dc-Dc converter, but make sure its a switching converter as they are much more energy efficient compared to a linear regulator Dc-Dc. 3 of these could also work: https://www.amazon.com/dp/B00VUHVX6W/

Edit: I just realize you need 4 (not 3) * 5V/10A, or 200W power.

Yeah, avoid anything that says gun. Soldering guns often don't have isolated tips and are too big for hobby soldering unless you really need the power for huge wires and chasis mount stuff like Nico said. Even if you are working with heavier stuff you can pre-heat with a hotair tool and finish the soldering up with the iron.


Here's a link for reference on the kind of rework station Nico is talking about.
https://www.amazon.com/TXINLEI-8586-Soldering-Different-Desoldering/dp/B07FJ6PNHF/


You can find cheaper one's off AliExpress or ebay but much bellow about 60 dollars and you're going to sacrifice basic quality and saftey. A lot of the super cheap kits don't have ground properly wired inside, if you decide to get one make sure you open the unit up and take a peak inside to ensure that it's grounded properly.

I completely agree with the choices and the Arduino statement as so many electronics beginners want to jump right in to Arduino and microcontroller usage without having any base electronics knowledge which is really required to use them properly.

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That is one reason the 2nd Edition of Make: Electronics stands out as the better choice IMO if your only buying 1 book as it starts out with very basic circuits, gets you the fundamentals, and the progresses all the way up through Arduino usage at the end in the last few experiments. Their are also some premade kits the author suggests for the book. They are a bit pricey but they make it a lot easier for the beginner to have all of the correct parts on hand and sorted while reading each experiments.

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Book: https://www.amazon.com/dp/1680450263

Kits: https://www.protechtrader.com/Make-electronics-component-pack-1-2nd-edition

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If you don't have any documentation on the device to determine its power consumption, get a cheap switching DC bench power supply and you can measure how much power the device will draw. You will need to know at least what voltage the device is expecting because overvolting will likely damage it.

You can get a bench power supply that does from 0-30V at up to 5A draw for as low as 60$ on amazon. I got one that does 0-30V up to 10A for about $120.

Here is the one I bought:

https://www.amazon.com/gp/product/B07ML2MP9Q

Attach the lab power supply as the power source, then turn the voltage knob until until the voltage matches whatever the specs indicate (be careful not to overvolt). Turn on the device and the digital readout will tell you how much it is drawing in amps. Take that reading and buy a power supply adapter with 10-20% more to handle spikes in draw that might occur.

Note that "wattage" is just the amps*voltage, so if was at 24V and the readout showed it was consuming 2A, then that would be 48W and buying a 24V 60W power adapter would likely be enough. You can always go higher on the wattage/amps as long as the voltage is correct. Devices will draw what they need, the power adapter wont send more, etc. So, given the example above, buying a 24V 100W adapter would be overkill and likely be more expensive, but it wouldn't damage anything. This is why its great to save old power adapters from laptops and toys as they can be reused in many cases.

Another option to measure draw is to start with a power adapter that provides more than enough wattage, put a voltmeter in series with the circuit and measure the current with the voltmeter. You do have to make sure that the voltmeter you are using is fused for the upper end of your expected current draw. Most multimeters have two current options, a very low current one and a 10A one. The terminals will be labeled as such.

I bought this one and some random bits for it (not sure what they're called, maybe pin housing?), and everything works great.

$23 isn't bad. The end result is worth it, and it's much faster than soldering for me

You buy the $25 ratcheting ones from amazon.


I have some $600 - $900 crimpers, but DuPont like in the picture doesn’t require it.

There’s a lot of skill involved with it, don’t solder your wires to the pins, take the time and get good with them.


IWISS SN-28B Crimping Tool for AWG28-18 Dupont Pins https://www.amazon.com/dp/B00OMM4YUY/ref=cm_sw_r_cp_api_i_eKYSDb81BFEFY

Assuming you define a smart charger as a charger capable of charging individual cells in a pack evenly and expeditiously I would say it's not required. OP can purchase a less expensive battery protection circuit ("BPC") or protected cells (18650s with the BPC built in) and lower his charge rate to a meager amount -- but even a 1A charge rate would be fine and charge the pack in ~4 hours. The inexpensive replacement for the smart charger would then be a constant current regulator. There are lots of versions of these, some with both a voltage and current display, and of course they can be dirt cheap when purchased from your friendly Chinese reseller.

I'm not saying your answer is wrong I'm just throwing it out there as another option.

Current will be self-limited by the boost controller I would think.

How hard do these shock people, do you know? Shocking people is pretty easy. You could just re-use something like this: https://www.amazon.com/Amazing-Roulette-Electric-Shocking-Game/dp/B07HYJPLC6/

https://www.aliexpress.com/item/33007353192.html

This might be bass-ackward but you could rig a small peristaltic pump to draw 5ml of water from the tank into a test tube, and another to drip-in the usual chemical test kit solution, then a webcam (or other optical sensor) to compare the color and produce a digital result. After testing, you would need to tip and flush the test tube a couple of times. It sounds like you would need 3 stepper motors, and these $2 ones might do the trick: https://www.amazon.com/Longruner-Stepper-Uln2003-arduino-LK67/dp/B015RQ97W8/ref=sr_1_4?keywords=stepper+motors&qid=1557919422&s=electronics&sr=1-4

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There are plans on Thingiverse for 3D-printed peristaltic pumps made from stepper motors and skate bearings.

Could you instead record the video, in SW convert the file into side-by-side, and then output over two composite outputs?

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I.e, use the existing HDMI port, find an HDMI-composite converter, and that powers the first screen. The second screen needs a USB-HDMI+HDMI-composite or USB-composite converter. When the video is played back, it's expanded such that half is on the left and half is on the right.

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https://www.amazon.com/Brisk-Links-Converter-Adapter-Display/dp/B078X4Z1X2/

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2x of https://www.amazon.com/Electop-Converter-Composite-Adapter-Supporting/dp/B07BVPV466/

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(No idea how good these products are).

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Some solid recommendations, these 2 books:
Forrest Mims: Getting Started in Electronics
Buy it: https://www.amazon.com/dp/0945053282/ref=cm_sw_r_cp_apa_i_MYa-AbTX971NC

Free to view or download here:
https://www.scribd.com/doc/19963886/Forrest-Mims-III-Getting-Started-in-Electronics-Radio-Shack

Make: Electronics: Learning Through Discovery
Buy it: https://www.amazon.com/dp/1680450263/ref=cm_sw_r_cp_apa_i_kZa-AbGYCSCM1

Also (arduino is great; but if you work through these books a little bit first you will be light years ahead when you start with arduino having learned the core concepts)

Checkout the Make: Electronics book by Charles Platt as their are quality electronics kits for them and should be exactly what you looking for as they start out with beginner circuits on breadboards and move on to soldering PCBs and even has some microcontroller programming projects at the end on a Arduino. The author recommends some component packs designed to follow the book on his site I'll link below that are complete and well done. I have used the book and kits myself and suggested them for a few others looking for similiar thing and never had a complaint about them.

Careful though as the Chaney kits do not cover the whole book, only the Protechtrader ones do as the authors site mentions


http://www.plattkits.com

https://www.amazon.com/ProTechTrader-Make-Electronics-Component-Educational/dp/B01EKO6FYQ

https://www.protechtrader.com/Make-electronics-component-pack-1-2nd-edition

https://www.amazon.com/Make-Electronics-Learning-Through-Discovery/dp/1680450263

It's that simple.

The switch is a 3-way switch, and they would typically either use 30/60/90 watt or 50/100/150 watt bulbs. Probably the former in this case.

If you go with LED lights, they take only about 3 watts per string, and the switch will handle that easily.

You need a plug like this:

https://www.amazon.com/Leviton-102-WP-016-00102-0WP-Outlet-White/dp/B000H5WIR6

Cut off the current bulb, wire in that socket, and you'll be golden.

Yeah looks like a 3528 chip so..https://www.amazon.com/HitLights-Neutral-Premium-3528-16-4-UL-Listed/dp/B01A79H4GQ/ref=sr_1_39?keywords=3528+led&qid=1557059842&s=gateway&sr=8-39

Cheaper on ebay:https://www.ebay.com/itm/Red-Blue-Green-RGB-RGBW-5m-10m-3528-5050-150-300-600-LED-Strip-Light/222114743006?hash=item33b71202de:m:m8r24OzTRDL9FJEgmLGYh2g

If what your putting it in has any type of heatsink you can go with a higher power chip, but you need to look at your power supply etc.

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https://www.dhresource.com/0x0s/f2-albu-g1-M01-F8-74-rBVaGVY9oc2ABAzRAAJZcqvm28k012.jpg/led-strips-kit-5630-5050-3528-smd-60led-led.jpg