Time to get my feet wet Making an RGB led Heart necklace (with heart shaped pcb) - Page 1
Forum section: electronics / beginners

author: Astaldoath
author_rank: Contributor
timestamp: April 04, 2018, 04:11:19 am
content: Im looking for some advice at that im completely new to making a pcb, layout, picking parts (i understand a bit about the parts from watching dave and many other channels in youtube)I want bright leds. All i will have to work with will be a hakko 888fxd station 65 watt. (or should i go for a ripoff of the 921, i think thats the model) that uses the heater element in the tip? or will the 888fxd do me fine?Also im not sure what kind of leds to go with. I do want RGB, i dont know weather to go with SMD or Through hole. I know SMD is harder and my hands arent very steady.Basically I want to make a PCB shaped like a heart, and have like several sizes of hearts within the one heart (does that make sense?) like a larger amount on the outside, then another row with less, another row with less, and so on until I have the heart shaped PCB completely filled with leds in a heart pattern in it.I was kind of thinking making them seperate almost like how some pcb have notches cut out, like have the outer set of leds be on a part of the pcb, but then have a smaller heart still connected to the pcb with less leds. and so on and so forth instead of 1 big heart shaped pcb, have it be in sections kinda. I will try to MS paint a quick idea tomorrow as its 12pm eastern atm.If i would use the seperated idea I was planning on having each section glow 1 color at a time, Example - Outer section all Purple/pinkish, next all blue, next all green, next all yellow, orange, and red finally but allow the user to change them with either a remote or some kind of breakout board attached to the heart pcb that they could mount inside a jacket or something. Ultimately this PCB would become a necklace like the RGB bowtie dave got on one of his Mail bags.Main points:SMD or Through holeMaximum BrightnessDiffuse or not diffuseand maybe a brand of LEDs that are known to be very bright. I started trying to learn Diptrace today and will continue with that. I was looking on adafruit because they seem to have a lot of addressable and multiplex-able LEDS and easy ways to drive them for clothing or jewelry items.I really wanna do this as I have no job and im disabled but dont get disability anymore (long story) I will be able to afford all the components and the manufacture of the PCB's though.Any extra advice is also appreciated.If I go SMD im thinking of using thesehttps://www.adafruit.com/product/1655

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: April 04, 2018, 07:49:47 am
content: Quote from: Astaldoath on April 04, 2018, 04:11:19 amUse SMD, most people use SMD these days for a good reason. You're able to increase layout density and as scary as they look for a novice, they are actually unbelievably simple to solder given the correct tools. On that note, the 888d is fine for SMD work, it all depends on the tip, flux and solder you use.As for LED's, from my personal experience, you would want to diffuse if the diode is going to be facing anyone's eyes, they get REALLY annoying due to their eye-piercing nature. (Of course, if you diffuse you will lose intensity)Using Digikey to select a part, I too arrive at:https://cdn.sparkfun.com/datasheets/Components/LED/WS2812.pdfMore importantly, You will also have to take into consideration other key design aspects that you have neglected to mention such as:- Controller: PIC? AVR? 8 bit micro?- Power supply: Batteries? boost converter? (they are 6-7 volt LEDs)- Interface: Buttons? Sensors? USB? One time programmable? (You did mention a remote, but not any specifics)- Misc: Any other features that you might need?

author: Ian.M
author_rank: Super Contributor
timestamp: April 04, 2018, 08:30:25 am
content: WS2812 and similar intelligent LEDs aren't particularly energy efficient. They typically use a PWMed constant current LED driver on the chip, and any excess voltage above the LED Vf + minimum headroom for the constant current circuit just turns into heat. Therefore its desirable to operate them as close as possible to their minimum rated operating voltage of 4.5V as you can.Powering them compactly is an issue - a single coin cell doesn't have enough voltage, and two would be on the high side of what's permissible. Also with a nominal current of 20mA per LED die, each can draw 60mA all on, so the total power required adds up quite rapidly. One approach would be to power it from a single 18650 cell USB powerbank. Micro USB plugs aren't particularly compact so it may be best to hack a retractable (self-windup style) USB lead cut off the end and solder the wires directly to the back of the board, with a dab of epoxy for strain relief.As to what to control it with, well for a one-off you probably want Arduino compatibility for easy 'hackability' by non-nerds. Use a USB capable ATmega that's supported by the Arduino IDE, and you wont have to mess with USB interface chips, or building a custom remote, or programming cable. You may want to consider a Bluetooth module if you think your coding skills are up to writing a phone app to control it. If not, then one or two buttons to select an effect from the choices given by the sketch that has been loaded into it would be the way to go. They could either be physical switches - miniature tactile button switches, or capacitive touch pads directly handled by the ATmega.Don't forget pads for AVR ISP so you can initially flash the ATmega with an Arduino compatible bootloader.

author: Astaldoath
author_rank: Contributor
timestamp: April 05, 2018, 01:38:05 am
content: Im thinking of using either like a micro arduino, or a teensy from adafruit, or just building something built in that can drive the LEDs which i would have to research.BTW here is my crappy image of my ideaNow bear with me its done in paint i could do it better on paper.When i say seperate pcbs as the green part, its not going to be seperate, i plan on having it all 1 PCB but cuts like a gap between them I dunno why I just think it would look better like that, if the company would have to charge me a lot more then ill just do a solid heart, without sizing cutouts so it looks like a heart inside a heart inside a heart inside a heart. If i can do the cutouts I think 6 separate sized hearts going from the biggest size to the solid little one in the middle would be what I would be planning on doing. Im gonna post on adafruit and see which of their boards would be best to control the LEDS with. Either way, cut out or not I want to place the LEDS in a heart pattern around it so I can do one outline in 1 color, another color up to 6 seperate colors at once, and either have a IR remote to change the color. Like some of the LEDS strips that are prebuilt use. I also will have to figure out the power supply part to power all the leds. Im not sure how many I plan on putting on each ring of the heart im thinking between 10-20 LEDs so it will be bright enough.However if all the color changing ect.. causes me to much grief at first I will just use set rows of LEDS, like Red, green , blue, purple, orange (if they dont have the color i want in the brightness i want ill use RGB leds and im talking through hole this time mind you, if the SMD and such gets to be to difficult atm, then I can upgrade as I learn more)Here is my crappy image idea and it does not do the idea i have any justice at all i just cant use paint lolThis may give a better idea, something like this, in heart shape, and 1 heart inside each other but still being a solid PCB just with air gaps around the outside like the colored LED ring in this image

author: hugo
author_rank: Regular Contributor
timestamp: April 05, 2018, 06:22:38 am
content: Something to inspire you:https://dmitry.gr/?r=05.Projects&proj=22.%20Vday%20Hearthttps://dmitry.gr/?r=05.Projects&proj=13.%20Greyscale%20LED%20matrix%20pendant%208x8BTW are you in love?

author: Astaldoath
author_rank: Contributor
timestamp: April 07, 2018, 06:54:21 pm
content: Quote from: hugo on April 05, 2018, 06:22:38 amYes i am infact in love and just got married hehe thank you, but i wanna make one for my wife, for my niece and a few other young girls in my life whos parents arent doing the best for them ( one little girls mother is shooting crack and either heroin or on methadone and we were friends but me and my now wife quit dope thank god. I took the dope cause of the pain im in and it helped but in the end it wasnt worth it I wish i could just get a decent doctor). I always wanted a daughter and life just didnt have it plans for me atm. I know the mothers/ fathers of any of these girls so im not a perv, but i know kids love light up stuff and it would make em feel special.The first one is very close to what I wanna make. 2nd one not so much i mean i could do something like that adafruit has cards that can be multiplexed they are single color though but you could draw a name or image on the leds with it.

author: Audioguru
author_rank: Super Contributor
timestamp: April 07, 2018, 10:59:12 pm
content: The Adafruit LEDs use 18mA to 60mA from about 6V which is heating of 0.1W to 0.36W. If you have 30 LEDs crowded together and lighted then the total heat is 3W to 10.8W which will cook them unless they are cooled with a fan. A battery will be huge or will die in a few seconds.

author: Astaldoath
author_rank: Contributor
timestamp: April 07, 2018, 11:51:38 pm
content: Quote from: Audioguru on April 07, 2018, 10:59:12 pmThe leds i looked at were 20 ma max i believe, Im not sure how many im gonna put i need to find a good resource for learning a lot of this stuff instead of bugging people on forums. I mean they have 9x17 boards of leds that arent to hot, Im sure there is a way to work around it and im thinking a LI-ON pack either the small ones with the plug the sell on adafruit or a cell with a cell holder that can go in a pocket or somethingOk it seems i will be using a ready made microcontroller board instead of integrating it and doing all that myself in the heart shaped board.Such ashttps://www.adafruit.com/product/1501https://www.adafruit.com/product/659https://www.adafruit.com/product/1222or a small arduino board so thats one thing off my chest, the rest is the power, code, buttons and leds ect..

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2018, 01:01:21 am
content: Brightness shouldn't really be an issue. Most modern LEDs are incredibly bright, I have some generic 0603 SMT LEDs that are too bright to look at directly when run near their 20mA max. This is especially true of the green and blue ones.

author: Astaldoath
author_rank: Contributor
timestamp: April 14, 2018, 04:25:12 am
content: So do you guys think its smarter or better to go with a prebuilt board to do all the led driving or should I look at building the driving and such in to the pcb to make it cheaper, cause some of the boards that can drive leds and are programmable cost 5-20 dollars

author: Ian.M
author_rank: Super Contributor
timestamp: April 14, 2018, 08:50:45 am
content: That depends - its already well on the way to becoming the sort of obnoxiously large 'bling' that 95% of women wouldn't be caught dead wearing, and now you want to further encumber it with a pre-built MCU board!An Arduino or similar MCU board is great when you are prototyping something like this but should *NEVER* be part of any space or unit cost constrained final design unless you have done the design work to prove that using a bare MCU wont make it smaller or cheaper.

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: April 15, 2018, 11:05:27 am
content: Quote from: Astaldoath on April 14, 2018, 04:25:12 amIMHO. Go all out, design every aspect of the board. You will get a sense of achievement and it is well worth it as you also learn a LOT from the design and layout process.My guess is that you'd only need to layout the microcontroller (and supporting components), buck/boost converter and LEDs.

author: Astaldoath
author_rank: Contributor
timestamp: April 18, 2018, 09:18:27 pm
content: ok since i didnt take electrical engineering are there any good books I could learn from? Ive been watching as much as I can online but people dont exactly explain what this does or why, i get the basics ohms, resistance, capacitance, why you need a diodes for reverse feedback stuff like that. I mean Im sure I could calculate how much power i need for the LEDs I just dont know how to build a buck.boost converter or if they are built in to a micro, i was thinking of using the same atmel as an arduino mega 2560. Im not too firmiliar with what micros are good for what yet, ive been trying to look up LED driver chips when ever i feel good enough.Plus i need to learn how to layout a PCB for someone to make for me with PCB design software and I have 0% experience in that. So ive been looking for friends that know how to use various CAD programs. I thought everything built in to my piece would be more cost effective also. These arent meant to be jewelry, they are meant for kids or people who wanna wear one to a party or somethin.

author: Audioguru
author_rank: Super Contributor
timestamp: April 18, 2018, 10:13:57 pm
content: Each LED has red, green and blue. The max current of each color is 18mA isn't it? Then all three colors at the highest PWM brightness is 54mA.

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: April 22, 2018, 08:39:43 am
content: Quote from: Astaldoath on April 18, 2018, 09:18:27 pmA lot of people recommend 'The Art of Electronics', a big book, but a good all-rounder book. If you want a textbook that is more specific to certain disciplines, I will gladly advise.As for the buck and boost converter. Texas Instruments has an online calculator applet, named web bench which will do all the work in designing a buck/boost converter.And yes, some microcontrollers may have built-in converters (ex. MSP432Pxx), however, they are NOT to be externally loaded and are ONLY for providing core voltages for the processor. (you wouldn't even be able to pull anywhere near the amount of current out of the internal converter anyway). Most microcontrollers operate in LDO mode anyway, but switching mode will save you some power consumption, would it be a significant amount to warrant the implementation? I don't know, depends on the current draw of the rest of your system.Again to pick a micro you need to further specify your requirements, i.e. Power consumption, IO, peripherals, development environment. Digikey or other sites with parametric searches can help you narrow down component choice.As for PCB software, you choose and you learn. Even at university level that is how it's done. If you want the ducks guts/rolls royce of CAD/CAE programs, go for Altium Designer. Or you can go for their much cheaper alternative, Circuit maker. Theres also eagle, kicad, the list goes on.Cost effective would be to roll everything on your own. No use of modules. But then again, some people argue the cost of time is more valuable than other tangibles.

author: Eka
author_rank: Regular Contributor
timestamp: April 22, 2018, 10:39:41 pm
content: Places like AdaFruit have all the schematics for their board products published online. Take a look at the Li-Ion battery chargers made to charge from USB and power a device from the LI-Ion battery. Look at the manufacture's data sheets and application notes for the chips used. Copy the circuit into your device if you like what it can do for you, and can find the parts in stock. You now have power which I usually just punt and buy a DC-DC module. They also have plenty of projects showing how to use LEDs. Scavenge the circuits and code that do what you want to do. I learned a lot about how to design electronic circuits from manufacturer's data sheets, and application notes. Nothing like seeing a working example, and modifying from there to get what is really needed for the project.

author: Astaldoath
author_rank: Contributor
timestamp: May 05, 2018, 03:09:04 am
content: Im still here, having some bad luck with my health, may be out of the game few a week or 2 at the most, hopefully less, had 2 rotten teeth pulled the last 2 days after i did, been feeling fluish, dizy ect... starting to feel better, just deathly afraid of dry sockets. Will keep pushin to making the necklace I wanna make a reality.If you wish and are christian or even if you arent christian (please pray for me, for my health and so I dont get a dry socket guys, i know ya hardly know me. Thank you)

author: Astaldoath
author_rank: Contributor
timestamp: May 28, 2018, 06:14:02 pm
content: Well i guess im not doing exactly what i wanted but i am going to bet getting my feet wet, trying to fix a monitor and tv with both the same symptoms, power light on, no screen, except my monitor the power light died too (maybe i changed outlets before it died). Will be back to this eventually, good news is I think i can get my soldering iron soon, im gettin the ts100 that comes with the 19v psu that almost runs at 2.7 amps, 24v/2.7 amps is shown what it uses when on 24vs on a good bench supply.If fixing the caps on the tv and monitor dont work ill probably be making a thread somewhere hehehe. I need a free tv

author: james_s
author_rank: Super Contributor
timestamp: May 28, 2018, 10:28:11 pm
content: I've fixed probably 20 LCD TVs that had nothing more than bad capacitors. That's not always the problem but it's a good place to start, usually they're so bad that the tops are bulging and sometimes electrolyte has leaked out.

author: Eka
author_rank: Regular Contributor
timestamp: May 29, 2018, 04:43:24 pm
content: TV and computer addictions must be strong. It's surprising how many couldn't wait for a day diagnostic, then a day or two for parts orders. I'm one to two days ground from DigiKey. So all my TVs and computer monitors but one are freebies from those who couldn't wait. It wasn't like I was charging my friends bench time, just parts. By the start up sluggishness on this one, I expect its backlight to go soon.