Yes, with LEDs you can achieve quite nice effects. If you only want one LED to light up, it's very easy and you don't need any electronics except a resistor.
16 hours ago, cloakfiend said:Nice, I like it! I ewant to work with leds more... I did a bit back in the day but my friend did all the electronics. I want to do glowing eyes and such on a few of my models. Not sure really where to start, I want to keep it simple and minimal.
Google for "simple led circuits" and then select "images". This shows the setup.
Always keep in mind: LEDs do need a resistor to limit current, otherwise they burn out! Usually the voltage over a LED is between 1.6V (old red LED) and 2.5...3V (blue and white LEDs). The recommended current for a nice illumination can go from 1mA to 10mA usually, depending on the LED. Don't come near the maximum current through the LED, always stay well below 50% of the maximum.
So you need to look up the specs of your LED, or measure them:
- normal voltage over the LED= Vled = ?
- recommended current through the LED= I = ?
What battery or charger are you going to use (I would recommend a 5V or 9V charger):
- sourcevoltage = Vs = ?
And then calculate the resistor as follows:
1) resistorvoltage = sourcevoltage minus LEDvoltage = Vr = Vs - Vled
2) resistor = resistorvoltage divided by LED current = R = Vr / I
3) power dissipation in the resistor = current multiplied by voltage over resistor = P = Vr x I
Example:
Imagine this are the specs:
- Vled = 2.2V (=voltage over LED, from the specs of the LED)
- Vs = 5V (source voltage, as usually found in chargers for charging USB devices or smartphones)
- I = 5mA (=recommended current through LED in the specs)
Then:
1) Vr = Vs - Vled = 5 V - 2.2 V = 2.8V
2) R = Vr / I = 2.8 V / 5mA = 0.56 kOhm = 560 ohm (take the closest available standard value)
3) P = Vr x I = 2.8 V x 5mA = 14mW (then add some spare: triple this value and take the next higher available resistor series, so it does not get hot: for example take a resistor of 250mW, a very common series)
4) add an on-off switch.
That is all. You values may be somewhat different, but this is the principle.
Basic scheme
But do recalculate the resistor value according to the specs of your LED and your sourcevoltage or battery voltage!!! It may differ.
Usually the long pin of the LED is the plus-terminal. And the pin connected to the "dish" inside the bulb is the minus-terminal. Usually, but check it. It only works if you connect the plus-terminal of the LED to the plus-terminal of the battery or source, not vice-versa.
Plastic LEDs like these can be grinded or reshaped with a Dremel and cutting disk, as long as you don't hit the wires and chips (also not the very thin wire on top of the chip). But they do get fragile. I used to do that in model trains and cars, to make them fit. But don't cut/drill into modern white LEDs.
Typical resistors. The color bands indicate the resistor value. Google for it.
That is all there is to it. Use a battery charger with short-circuit protection. And/or add a mini fuse yourself.
(All pictures via: "Google --> Images". Credits to the original photographers/designers.)
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cloakfiend 996
Thanks for the write-up!
I'll try the 9V battery first. Ill ask someone to explain to me the basics when i get the stuff, as I know ill just get it wrong, and it will save time at the beginning. Once I've done a few hopefuly I should get the hang of things! Off to ebay/amazon/internet now!
one is ok but seeing as ill try for some eyes a lil diagram for two would be nice! 😉 I assume a series circuit or something? not sure how it will affect the resistor requirements? will i need more or is the current good for two if its good for one?
Edited by cloakfiendIf you use a 9V battery, and you put the LEDs in series, it will work with the same resistor value, but just give a bit less light.
But usually I would prefer to recalculate the resistor:
voltage over resistor = battery voltage minus first LED voltage minus second LED voltage.
Vr = Vs - Vled1 - Vled2
For an educated guess, that would be: 9V - 2V - 2V = 5V over the resistor (as a crude order of magnitude). Use two identical LEDs.
And then calculate the resistor, based on the recommended current through the LED.
If it is a high-efficiency LED with low power-consumption, the current could be 1mA. Then the resistor would be:
R = Vr / I = 5V / 1mA = 5KOhm
If it is a medium efficiency LED, with a current of 5mA, it would be:
R = 5V / 5mA = 1KOhm
For a LED of 10mA:
R = 5V / 10mA = 0.5KOhm = 500 Ohm. This value does not exist, so we take a nearby very common existing value: 470 Ohm, or 510 Ohm.
For a very old LED, or a brighter LED that requires a bit more current of 20mA:
R = 5V / 20mA = 0.25 KOhm = 250 Ohm. This does not exist, so we would take 240 Ohm or 270 Ohm.
For the existing resistor values, Google for: E24 resistor series
Among the images in Google, you will then also find the color codes.
If you are not familiar with electronics, avoid very high power LEDs like those used in spots or in traffic- or billboard signs. These may get very hot and require special cooling and mounting features. Tiny low power LEDs like in keyboards, stereos, etc..., don't get warm if a correct resistor is used to limit the current to the recommended value.
If you want to buy new LEDs, search for low power high efficiency LEDs, because: 10x less current = 10x longer battery life. Search for 1mA or 2mA LEDs, provided they give enough light for your purpose. This may sometimes be very hard to guestimate from the specs, so you may want to try various types. It is a long time ago since I bought LEDs myself, so I can't say what is on the market today. About 20 years ago a typical low power high efficiency LED of 3mm diameter consumed ca. 2mA, but that is 20 years ago... And LED-voltage was 1.65V for red LEDs, 1.9V for yellow, 2.2V for green. Hence my 2V guestimate, which is usually okay for red, orange, yellow, yellowish-green. However, blue, white, and "traffic green" LEDs (=blue chip with phospor on top) usually are around 3...3.5V. But different values exist. Look them up in specs of distributers like RS-components, Farnell, etc...
Mr. Google is very helpfull today (credits to the original photographers):
However, solder the wires, instead of wrapping.
Or try these boards for experimenting: they are very handy, but watch out for short-circuiting wires:
With this board you can try lots of different resistor values and LEDs in a short time. I used them a lot.
Note: LEDs have virtually no internal current-limiting features: if you apply a too high voltage without external resistor, or if you short-circuit the resistor by accident, the current can get very high and immediately burn out the LED. Don't ask how I know... :-)
So, *always* use a separate resistor for current limiting, and never rely on the very unpredictable internal resistance of batteries, power supplies, or LEDs.
Further, when plying the leads, use a plier to grip the wire close to the LED, and bend it around the plier, on the side away from the LED. So don't put too much mechanical stress on the plastic housing of the LED. Pulling hard on the leads of tiny 1mm LEDs could cause them to break, since the plastic is not very strong. Here too, don't ask how I know... :-)
These are a couple of very good educational Youtube videos on this subject:
- https://www.youtube.com/watch?v=Bozb8t6d1Xk
- https://www.youtube.com/watch?v=Yo6JI_bzUzo
- https://www.youtube.com/watch?v=NfcgA1axPLo
- https://www.youtube.com/watch?v=VSpB3HivkhY
This reply is a bit longer than I intended, but fortunately I can type very fast. Also, I realise this is a bit off-topic concerning 3D-printing, but I think it is close enough. It may also be usefull for people who want to modify their 3D-printers to mount some indicator LEDs in it. For example you could mount a LED on the bed heater or on the (cold side of) the print head and nozzle, to see when it is on. Carefully calculate resistor-values (Ohms) and power-ratings (Watt).
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1 hour ago, geert_2 said:Also, I realise this is a bit off-topic concerning 3D-printing, but I think it is close enough.
Don't worry, it is fully on topic because Cloakfiend has asked for help and your answer is really helpful and perfectly explained.
So shame on me that I only wrote "you need a resistor" 😞
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26 minutes ago, Smithy said:Don't worry, it is fully on topic because Cloakfiend has asked for help and your answer is really helpful and perfectly explained.
So shame on me that I only wrote "you need a resistor" 😞
No shame on you. We do not always have the time to fully explain things. Further, I am working in an educational institution (university), where we are by law required to: "provide education, research and service to the community". Often I also have to provide explanations and guidance to collegues and PhD students about computers, software, and laboratory equipment. So I am used to it, and it fits within my job. Also, I enjoy sharing knowledge, so I don't mind doing this at all. :-)
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Hello, here is one of my last projects. It`s a mini shredder, made of PLA.
We tested the shredder with gummy bears, paper and popcorn. 😉
- 7
Well done!
On 4/20/2019 at 1:21 AM, Smithy said:Well done!
pretty sure the gummy bears feel different about this 🙂
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On 4/20/2019 at 12:25 AM, jtronics said:Hello, here is one of my last projects. It`s a mini shredder, made of PLA.
We tested the shredder with gummy bears, paper and popcorn. 😉
This looks like a fun project for kids.
Did you print each cutter-blade assembly in one piece, or print each blade separately and then mount them on a rod?
cloakfiend 996
taking a break from movies and trying some cuteness. but it seems as either my z screw is dirty or my printer is unable to close a semi sphere smoothly, hence the random line. its 1.2 wall so it should be plenty, its on both models, ill try a few tests in the meantime! miaow, pusheen kitty inspired.
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kmanstudios 1,120
First Experimental PP prints. The prints were finished more than a month ago. I have had liquid sitting in them all this time and no leaks. All I have to do is find a silicone seal for the cap and it will be water tight. Literally. Once I have the silicone gasket in place, it will be really spiffy.
These are the bottle designs:
So, the first on the left is the first attempt. Nothing special. The the 'K-Bottle' was the second attempt (yeah, yeah, I know it is out of order in the image) where I wanted to figure a proper way to make 'logo' and design stylings more complex. The "Tokah-Cola' bottle was spurred by all the news about beverage companies trying to figure how to make and market CBD infused beverages. So, I thought this would be a nice little drink.
These are the actual bottles with food coloring in the water.
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4 hours ago, kmanstudios said:First Experimental PP prints. The prints were finished more than a month ago. I have had liquid sitting in them all this time and no leaks. All I have to do is find a silicone seal for the cap and it will be water tight. Literally. Once I have the silicone gasket in place, it will be really spiffy.
These are the bottle designs:
So, the first on the left is the first attempt. Nothing special. The the 'K-Bottle' was the second attempt (yeah, yeah, I know it is out of order in the image) where I wanted to figure a proper way to make 'logo' and design stylings more complex. The "Tokah-Cola' bottle was spurred by all the news about beverage companies trying to figure how to make and market CBD infused beverages. So, I thought this would be a nice little drink.
These are the actual bottles with food coloring in the water.
Nice. And what method did you use for bonding to the glass?
kmanstudios 1,120
Believe it or not, my PVA slurry I make on the glass and a brim. I did not have an issue with the material. I was very, very surprised.
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Hello!
I'm fairly new to 3D Printing, building from a kit I've learned waaaaaaay too much about everything 😛
I've been learning Fusion 360 and fancied making a Mario Kart trophy. I found a really nice star medal on thingiverse so remixed it into it's own trophy with stand.
I then thought I'd try some gold spray paint on the star. Never used spray paint before and laid it on a little too thick. That's fine though. Doing things wrong when learning is OK 🙂
Here is the thingiverse link: https://www.thingiverse.com/thing:3591947
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Right you are, learing by doing is the best way. And apart from small imperfectoins one suffers on first try it is alway exciting if something new you try turns out more or less like imagined before. This encourages to try more and even if it fails you know so much more about how not to do that this is even amazing. I have no clue about Mario Kart trophies but for me done from scratch you did a great job.
- 4 weeks later...
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ShiryouOni 3
Hey all ! New here and to 3d printing in general, thought i'd post up one of my first semi succesful prints.
Mostly came out ok, had some warpage on the bed because I thought I could get away with a simple brim and not a raft, which seems to almost never work on my Tevo Nereus. Also had several layer shifts, not sure how to fix that yet. Still learning. All in all its still functional and working great !
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Smithy 1,146
Here my project from the last weekend. A wall clock, controlled by an ESP8266 microcontroller. The ESP controls a LED stripe to show the current time which is fetched regularly via Wifi from an NTP server. The clock contains 6 segments for the ring and 60 parts for the minute indicators. Red shows hour, green the minute and blue for the seconds.
Now I only have to find a nice place to put it on a wall.
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cloakfiend 996
Nice, I like it! I ewant to work with leds more... I did a bit back in the day but my friend did all the electronics. I want to do glowing eyes and such on a few of my models. Not sure really where to start, I want to keep it simple and minimal.
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