Our favorite food when hacking on code or electronics is a hot bowl ‎of noodles — and around NYC these are often called “noods!”

What ‎we've got here are flexible LED noodles, in different colors. Not good ‎for eatin' but they are good for cool lighting effects!‎

These are often seen in “Edison-like” LED bulbs, shaped into hearts ‎or stars, or just wound around to create a fun or warm lighting effect. ‎They’re made of dozens of LED diodes that are bonded together on ‎an ultra-flexible metal backing, then coated in colorful silicone for ‎protection. Since the LEDs are in parallel, you only need 3V to ‎light ’em up.‎

Add some mini, noodle-y neon bling to your miniature sets, ‎dioramas, dollhouses, mini-verses, what have you!‎

Electrical Properties

noods are comprised of many light-emitting diodes (LEDs), they ‎have a specific polarity, with distinct anode (“plus”) ‎and cathode (“minus”) ends. If a nood doesn’t light, you might just ‎need to flip it. The anode end can be identified by a teeny-tiny hole ‎in the metal end tab.‎

An inline current-limiting resistor is recommended. Try around 50 ‎Ohms if the supply voltage is close to 3V, and 220Ω around 5V. For ‎brief tests at these voltages, you can probably omit this, but for best ‎longevity it’s a smart thing to have.‎

noods can be powered directly off a 3V coin cell such as a ‎CR2032. This won’t be as bright as with a “proper” power source, but ‎for small items and props it’s a great effect. Because these cells are ‎inherently current-limited, no resistor is needed.‎

noods can be powered and controlled from microcontroller ‎output pins via digitalio (CircuitPython) or digitalWrite (Arduino), and ‎the brightness modulated and animated using pulse-width ‎modulation (PWM) via pwmio (CircuitPython) ‎or analogWrite (Arduino). Here are some things to be aware of:‎

Though most microcontroller GPIO pins are inherently current-‎limited, it’s considered prudent to add a current-limiting ‎resistor (as described above) so the chip isn’t continually ‎‎“redlined.”‎
Every microcontroller has different current drive ‎capabilities, with limits per pin, per port, and in total. This ‎information will usually be in the “Electrical Specifications” ‎section of the chip datasheet.‎
Some microcontrollers can sink more current than they ‎can source. That is, you might control more and/or brighter ‎nOOds by connecting the cathode (–) end to GPIO pins, and the ‎anode (+) to the microcontroller’s voltage and use inverted logic. ‎Again, check the chip datasheet.
Avoid using analogio (CircuitPython) or analogWrite() (Arduino) ‎to DAC-capable pins (true analog voltage out, not PWM, such ‎as on the SAMD21 A0 pin); LEDs require current control, ‎not voltage control.‎
Given the vagaries and differences among microcontrollers, rather ‎than controlling nOOds straight off GPIO pins, consider using ‎a dedicated LED driver such as the AW9523. This ensures consistent ‎peak brightness regardless of the type of microcontroller, and ‎dimming is performed via current control rather than PWM; the light ‎is perfectly steady and photographs well. Current-limiting is ‎performed by the device, so no per-nood resistor is needed.‎

noods could also be controlled with a WS2811 driver IC — the same ‎logic that’s inside NeoPixels! This does not make the nood per-‎LED addressable*, but…with three noods side-by-side (red, green, ‎blue)… could allow for a sort of color-controllable Neo-nood. The ‎WS2811 is a “sink” driver, so the cathode end of each nood connects ‎to the IC. The chip provides its own current control (18mA), resistors ‎aren’t needed.

‎‎* The highest density addressable item Adafruit carries is this half-‎meter NeoPixel strip, but it’s much wider and not as flexy as nOOds; ‎not really the same thing.‎

noods can be connected in series (end-to-end) with a ‎corresponding increase in voltage, e.g., 3V for one nood, 6V for two, ‎‎9V for three and so forth. You’ll still want a current-limiting resistor. ‎Lower voltages might suffice, e.g., two red nOOds might work from a ‎‎5V supply…you’ll have to experiment. Probably best and easiest to ‎work with these as parallel, not serial, components.‎

Physical Properties

Looking closely, you’ll see nOOds have a front face comprised of a ‎milky white silicone diffuser, and a back face that’s somewhat ‎transparent. The two faces aren’t always perfectly balanced, but ‎close enough for most tasks.‎

Dimensions

Allow ± a couple percent for normal manufacturing variances, but in ‎general nOOds are…‎

‎300 millimeters long from tip to tip, including the end ‎connector tabs
The illuminated section is about 285 mm long
Exposed portions of end connector tabs are about 5 mm long
Cross-section is not perfectly circular; about 1.7 mm wide, 1.9 ‎mm tall

Bend Limits

nOOds have an internal structure, with distinct per-axis bend ‎radii. Think of it like a tiny folding ladder…one axis can fold any which ‎way; the other is unyielding.

In the front-to-back direction, nOOds can be fully pinched; the ‎minimum bend radius is equal to the nOOds’ radius, about 1 mm. ‎That might be pushing it, but it’s possible.‎

On the torsional axis (twisting), nOOds tolerate a full 360° twist ‎about every 25 mm or 1 inch. Less is always better. Too much and ‎you might see individual LEDs pop off inside!‎

In the side-to-side direction…nOOds can’t and shouldn’t bend! The ‎trick here is to apply a mix of torsion and front-to-back bending. ‎Imagine a banked turn on a racetrack or highway…it’s a little like ‎that.‎

Thus, to achieve the most intricate shapes with the tightest ‎bends, nOOds would ideally be installed sideways. But as explained ‎above, the front and back faces aren’t always perfectly balanced in ‎brightness. From any reasonable distance, probably unnoticeable. ‎Tradeoffs!‎

Durability

nOOds’ flexibility makes them a delight to noodle around with. But ‎they’re not engineered for infinite noodling. Like any physical thing, ‎they stand a chance of eventually wearing out. We don’t know ‎exactly what that limit is or how to characterize it, but it’s likely a ‎function of bend radius, flexing duty cycle and some luck.‎

For maximum lifespan, treat these exactly as you would EL wire or ‎flex LED strips: bend them to a shape once and affix them to a solid ‎

support.‎

Realistically, you can probably work these into costumes and other ‎gently bendable items that see infrequent use (gloves, outerwear), ‎and they might last the lifetime of the item.‎

If a situation demands frequent, tight flexing, then plan for these to ‎eventually wear out, and design for quick replacement: perhaps ‎pluggable ferrule connectors on the ends, or screw terminals, or just ‎accessible solder points.‎

Prototyping with nOOds

The metal tabs on the ends of nOOds are too slim to make good ‎contact with breadboards. It might work for a quick test, but for ‎anything more involved will test your patience.‎

Easiest for quick prototyping is alligator clips, such as these gator-‎to-jumper wires in packs of 6 or 12.‎

For something better shielded from metal items on your worktable, ‎solder breadboard-friendly wires onto the ends, apply a little heat-‎shrink if you like. You can color-code each end for anode vs. cathode!‎

Attaching nOOds

Here are some ways nOOds might be attached to things:

Monofilament fishing line (e.g., wrapping around wire armature)‎
Clear thread (e.g., sewn to garment or to plastic mesh canvas)
Transparent sticky tape (adhered to flat surface)‎
Clear heat-shrink tube (wire armature)‎
Press into narrow channel; the nOOds rubbery surface should ‎grip in place (signs and 2D shapes) — a great application for 3D ‎printing or laser cutting!‎
Silicone glues are not currently recommended, as they can be very ‎picky about what sticks to what. Supply chain issues have resulted in ‎some glues being reformulated…a brand that works today might not ‎work the same tomorrow.‎

Tips & Tricks

nOOds can not be cut. Period. But that’s why this is tips and ‎tricks! Let’s do shenanigans…‎

You can simulate a shorter length by stuffing part of the nOOd ‎behind an opaque base or end piece where it can’t be seen.‎

tips_4

Multiple shorter lengths can be simulated by covering sections of a ‎single nOOd with opaque black heat-shrink tubing.‎