(Part 2) Reddit mentions: The best optoelectronic products

> Hampton Bay 5-Light Matte Black Chandelier

That's certainly better than what I have. And the price is fantastic. It's just that . . . I'm not in love with it. You Know?

What are you thoughts on something like this: http://www.amazon.com/Triangle-Pendant-Ceiling-Chandelier-Korea/dp/B00LXP7ENW/ref=sr_1_20?s=hi&ie=UTF8&qid=1406206957&sr=1-20&keywords=cree+100w+5000k


It's energy efficient, since it's an LED. I just. I wonder what it says about me as a person, you know? I don't know. I keep second guessing myself, and I don't want to end up as that "Home Depot" guy, or whatever.

I'll let /u/SoullessSin give specific recommendations, but any suitably sized and colored LED should work fine for what you want. Non-surface-mounted ones should be fine for your use since it sounds like you don't need really anything really tiny. You can get them down to 1.8mm like this, although something larger will probably be better for you.

You'll also want to pick up a resistor for current limiting.

Hi DIY!

I'm trying to assemble a list of products (via amazon prime for time and location reasons) to do a project with my partner on his birthday Sunday with a budget of $25-30. I think he'd get excited for (and I can manage!) LED paper circuits. Luckily we have a soldering iron and multimeter around the house. Here are the products I've whittled down to with no idea at all what I'm searching for except advice from tutorials:



Copper tape - Amazon link HERE


LEDs - Amazon link HERE


Batteries - Amazon link HERE


Do these choices look okay, and if not would you suggest any alternatives? Thanks so very very much for any help!

You can get them with power supplies on amazon for 21.99. those are 50w, but with the power supply might still be a better deal. You can find 100w white led's with power supplies from the same seller.


For my next light I'm going to do a 7:2:1 red/blue/orange all 50 watts. My blue-heavy LED panel kept my plants notably shorter and thicker than my other lights, I definitely recommend exploring that.


edit: btw I'm pretty sure it was in one of your first posts that I found out about COB led's. It was when I first started soldering this light. When I found out that I could have used way less lights I looked down at the 150 3w LED's and died a little bit inside. Then I ordered some blue 10w COB's to go on there.

It’s finally done (For now)!

I’ve been working on a Minty Pi since I heard about the Minty Pi project from Helder and Wermy. Because I missed the cutoff for the preordering system and there was no way for me to get one any time soon I decided to make my own.

As you might have guessed, yes, this isn’t my first attempt at making a small portable Retropie machine. Let’s just say, version 1 was a complete failure (but taught me things), and version 2 taught me the importance of space efficiency.

This is now version 3. It’s fully playable with anything for 4 face buttons and two shoulders. It has a 2000mah batter good for 3-4 hours of gameplay.

Here’s my parts list—

($13.99)Hiletgo 2.8 lcd screen - pain in the ass to work with but this website helped a lot.

($4.99)Adafruit PiGrrl 2.0 Gamepad - works ok for now.

($19.99)Adafruit Powerboost 1000C - probably overkill but it runs everything without a hitch

($14.99)3.7v 2000mAh Li-ion battery - works ok

($10.00)Raspberry pi Zero W - wish there was an audio out port

($2.50)10 6mm tactile switches - they work for now. Gaming past an hour kinda hurts.

($1.50)2 12mm tactile switches - nice feel for the usefulness

($1.00)SPDT slide switch - definitely helps to turn off the system

($2.97)Altoids tin - any flavor is nice

($Various)22ga copper wire
28ga rainbow wire
Electrical tape
Hot glue

The biggest pain in the butt was to get the screen up to enough refresh rate that I had very few issues with lag. I used this website to get the screen up and running (lots of testing) then tweaked the screen size (320x240) and the screen speed (12000000) till I could run SNES and Gameboy without many issues.

Edit: Added prices

I'm using 5mm LEDs for the GC. The pads are super sensitive to getting stripped, so I strongly recommend globbing on solder and connecting the two points, then heating the solder and removing the original LED with tweezers. After that, just pop some solder braid on it to suck up the excess and you're ready to get the new LED installed. As for what LEDs to grab, these are similar to the ones I picked up - https://www.amazon.com/Emitting-Diodes-Waycreat-Assorted-Arduino/dp/B071HV5F6L/ref=sr_1_8?ie=UTF8&qid=1523238346&sr=8-8&keywords=multicolored+5mm+leds - as a general rule of thumb for console LED mods, grab clear bulbs with colored diodes. Colored bulbs are super dim and the color looks washed out, you get way better results with clear ones.

There's a whole world of stuff, it really depends on what kind of thing he finds exciting.

Here are two ideas of things I think are really cool and would make a fun birthday presents for an Arduino fan.

Little OLED display

https://www.amazon.com/Heltec-Automation-HTDS-WI96-0-96inch-comminication/dp/B0742BJPNF/ref=sr_1_29?ie=UTF8&qid=1543406669&sr=8-29&keywords=oled+display

Basically an Arduino with built in WiFi ( and a lot more features )

https://www.amazon.com/HiLetgo-ESP-WROOM-32-Development-Microcontroller-Integrated/dp/B0718T232Z/ref=sr_1_3?s=electronics&ie=UTF8&qid=1543406789&sr=1-3&keywords=esp32

Would a bundled set like this be usable in my situation?

My ideal value resistors should be 150 Ohms and 100 Ohms. This bundle comes with only 200 Ohms. At that rating, will the LED's be bright enough under a 5v power supply? If it is, then I will just order this set as it is far cheaper than sourcing out the parts individually.

You mentioned 400 Ohms... can I wire up 2 200 Ohm resistors in series to get to 400 Ohms?

Difference in W looks like 36 versus 650. Is that a measure of the effectiveness of a grow light?

What do you think of this http://www.amazon.com/Galaxyhydro-Greenhouse-Indoor-Hydroponic-Lighting/dp/B00PH1MQV8 -- it looks like an older model so that might be a dumping price.


What do you think about a more concentrated source like this http://www.amazon.com/dp/B016NT1JO2?psc=1 versus an array like this http://www.amazon.com/MOKOQI%C2%AE-Advanced-Spectrum-Hydroponic-Growing/dp/B016NT1L36 in terms of effectiveness?


Is there no possible (practical) way to take something like this http://www.amazon.com/Geeetech-LED-Matrix-8x8-Display/dp/B007ZK4I10 and set the brightness very high and use that as a grow light?

first google result You'll also have to find a constant current laser diode driver, a module to mount the diode in which has a lens, and a heat sink to put the module on or in.

You can also get ready made modules like this But you would need to get a big heatsink for it. That tiny driver board might overheat as well so this probably isn't the ideal module for engraving. You'll want to end up with something like this. IF you want to make it yourself and need it to run constantly, I'd suggest drilling a hole in a computer CPU heartsink for the module.

You can find a lot more information about how to mount, drive, and assemble these things at LaserPointerForums and PhotonLexicon DIY sections. There is also /r/lasers Some of the message board members run web stores and sell all sorts of useful parts for this sort of thing, often made at home. The guy I used to buy from is closed now though. PhotonLexicon is mostly focused on laser shows, and LPF is more about laser pointers, but between the two you should be able to figure out what you need.

I believe the most common donor projector is a Casio m140, but it's been a long time since I've been messing with lasers and there may be better sources now.

Here are some cheap 7 segment displays. The wiring is pretty simple, just connect one of the pins on the 7 segment display to ground. The pin is usually marked with a white dot. Then connect an IO pin to each of the other pins and setting the arduino pin high will turn the corresponding segment of the display to light up. You will probably need a Mega for all the pins. Then create functions in the code which set certain pins high and others low to form letters. Then use the delay(1000); command to time things. It sounds complicated in words but its actually an easy thing to do hands on. Once you get the wiring done, if you tell me the pins, I might even be able to write all the code for you, then you could just copy it into your Arduino. Hope this helped!

I've done some cli stuff in the past, but I'm pretty rusty on it.

The display is this one the same store sells a P4 one that has reviews of people getting it to work with the adafruit hat. The rest of my setup is a pi zero w 1.1 with a soldered header (possible failure here, although I'm pretty confident in my soldering), adafruit rgb matrix bonnet, and usb hub


I'll probably start from scratch with an adafruit tutorial to at least get the display working. Some of my problems could be from my raspbian installation. The first issue I ran into was with the micro sd card I was using, so I initially installed raspbian full from NOOBS.

I'll feel better once I get the panel to display anything at all.

I believe they were 1/4W resistors. I got the LED's from a kit on Amazon, came with 30 bulbs and resistors for like $4. I used this handy calculator to help figure out how I wanted to wire it and what I would need.
Let me know if you end up doing it, I'd love to see how it turns out.

I'd buy a 10-slot USB hub for $10, and save even more. That drops the price per student down about 9 more dollars.

Pay $2 per SD Card Thats another $5 off. There are 2gb distros available for RPi; this is just for typing lessons.

Assume Model A, so $10 more off.

Disregard case, acquire creativity: cigarette packs, decks of cards, shoot: I kept mine in a motherboard ESD bag under the couch for 2 weeks. Thats another $9 off.

$3.60 for a fold up keyboard Thats another $6

Switch to a way lower resolution $6.40 LCD and save another $12.

Now I'm at $45 :) If I lived in Bangladesh and wanted to teach typing for $50, that's how I'd do it.

My only concern with all of this would be stable voltage levels...I've seen what the power lines look like in Bangladesh.

Wattage depends on what you’re trying to do, but you won’t find a unit small enough for that job above 1 or 2 Watts. That should be enough to engrave woods and acrylic, and probably cut almost nothing.

This could work.
https://www.amazon.com/Focusable-Cutting-Burning-Matches-Adapter/dp/B06WVHS3K5/ref=mp_s_a_1_3?ie=UTF8&qid=1537218156&sr=8-3&pi=AC_SX236_SY340_QL65&keywords=laser+2watt&dpPl=1&dpID=51m7Akat%2BbL&ref=plSrch

The issues with a project like that are:

1. Unenclosed, so you’ll need proper safety glasses for another $50-$100 as well as fume extraction unless you run it outside.
   
   
2. The print bed will be wrong, and depending on the wavelength of the laser, could reflect it with unfortunate results. You’ll need to rebuild the lower area to capture and diffuse the laser without damaging anything.
   
   I tried to do exactly the same thing last year and eventually realized that buying a small Chinese laser cutter would be easier, safer, more powerful, and generally far more useful, not to mention I wouldn’t lose my 3D printer to the cause. It can be done though, if that’s what you really want.
   
   

I think a moderately powerful IR flashlight like this one meant for use with night vision has a good chance of ruining any photos or videos if directed in to the lens.

Salut le FL ! J'aurais besoin d'un peu d'aide, c'est pour une idée de cadeau.En gros l'idée serait de trouver l'équivalent d'un lecteur MP3, mais dans un format plus grand, et fixe. Avec une capacité de stockage assez importante ou extensible par carte SD/Disque Dur. je sais qu'une tablette tactile peux faire ça, mais ce serait vraiment pour utiliser uniquement comme lecteur de musique, qui resteras toujours dans cette pièce. Je sais pas si c'est super clair...

EDIT : En gros ça : https://www.amazon.fr/Logitech-Squeezebox-Lecteur-sans-fil-num%C3%A9riques/dp/B002N203SW/ref=sr_1_1?ie=UTF8&qid=1481277863&sr=8-1&keywords=Squeezebox+Touch

Mais qui ne coûte pas un reins...

EDIT 2 : Bon vu le peu d'offres existantes et les tarifs prohibitifs de celles ci, je pense me tourner vers l'achat d'une tablette tactile qui fera office de lecteur. Vous avez des tuyaux pour un tablette tactile avec mémoire extensible jusqu’à mini 100 go, assez performante pour gérer la lecture et la navigation dans 80 go de musique, de préférence sous android ?

LEDs are extremely inexpensive - Example

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As far as the installation goes, I do believe it is relatively easy to install them, pending your ability to solder. I will link a tutorial on how to install them.

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LED Installation

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Hope I helped!

I did have some code for it, but I can't seem to find the file where I saved it. It was fairly simple though. I will keep looking, but you might write a new one before I end up finding it.

For the odometer, I think I am going to have a second arduino (the Leonardo) powering two of these 4x20 screens and doing all the communication to my vehicle's computer.

So I will need the Leo to be able to query the odometer (trip and total) data from the Uno. Is that something you are up to coding for? (I would feel like paying you extra for this integration. Honestly, I wouldn't mind outsourcing this whole thing just so I can get it finished fast. This is great)

CR2032 Button Batteries and 3 LED Lights per battery taped on to the top/bottom of the discs with Packing Tape.

edit: See through discs work the best (Champion, Proton)

That depends on the LED, the battery and the circuit. Let's say you get a low current LED (20 mA - https://www.amazon.com/gp/aw/d/B00UWBJM0Q) and an average 1632 battery (130 mAh - https://www.amazon.com/gp/aw/d/B00102JQIE). That's drawing 20 mA from a 130 mA-hour battery so you just divide. You'll get about 6.5 hours of light from it though probably a bit less since you'll want to size your resistor to allow a bit extra current for a brighter light. You would do better getting a 2032 battery - https://www.amazon.com/gp/aw/d/B00DORK4NE. It's only a little thicker and would give you 225 mAh.

Edit: just realized you posted a link to a product. I have no idea how long that would last but i would guess 6 hours would be an upper limit.

It's a LED bulb.
https://www.amazon.com/dp/B06XPV4CSH/ref=cm_sw_r_cp_awdb_t1_jZcOBbGP3B8D1

ok, I've switched plans to solder an entire system using these LEDs of lower voltage. Now I only ask, will two 1.2 AA batteries be enough to power them and do I need resistors?

Not including the 3d printer or filament, or my soldering iron and other necessary tools:

LEDs: $12.57

Resistor 47ohm: $6.12

Diodes: $5.59

Gateron greens: 17@ $.90/per