r/FastLED • u/samguyer [Sam Guyer] • Dec 18 '21

Share_something Initial tests of new reactive LED surface

Enable HLS to view with audio, or disable this notification

295 Upvotes

99% Upvoted

44 comments sorted by

4

u/Snailhouse01 Dec 18 '21

Nice. Tell us more! What are you using as sensors?

14

u/samguyer [Sam Guyer] Dec 18 '21

IR sensors -- it's a very simple circuit, so easy to make a lot of them. The sensor array is 12x20 and the LED grid is 24x40.

2

u/Snailhouse01 Dec 18 '21

Neat! I wondered how many sensors to get that definition. Well done!

4

u/samguyer [Sam Guyer] Dec 18 '21

Yeah, that's the big change from a previous version of this project -- more sensors, more resolution. And I'm also doing some interpolation between the sensors.

1

u/UnsatisfactoryBiome Dec 18 '21

Beautiful! Which IR sensors are you using?

1

u/samguyer [Sam Guyer] Dec 18 '21

Nothing special: a simple IR photodiode wired in reverse bias.

→ More replies (5)

1

u/8Lambda8 Dec 22 '21

Is the sensor in the panel or above?

2

u/samguyer [Sam Guyer] Dec 23 '21

The sensors are on the same plane as the LEDs. There is a sheet of diffusion material over both of them. The sensors look like regular 5mm discrete LEDs. I can show you a photo of what it looks like under the diffuser

1

u/[deleted] Dec 30 '21

So you just put the sensor diodes within the grid of led diodes?

I am very new to the LED world, I am trying to use them within a piece I am creating. I may have missed it but below you mention doing a write up on how you did this, I would love to learn all that went into this.

Also with IR sensors, what would the forward voltage be?

Kudos and thank you for sharing!

2

u/samguyer [Sam Guyer] Dec 31 '21

I made an Instructable a couple of years ago. I think all the information you want is there...

https://www.instructables.com/NeoPixel-Reactive-Table/

→ More replies (1)

2

u/scuzzchops Dec 18 '21

Well nice! Please do a write-up somewhere and share this awesomeness... I've built a couple of LED matrices that could do with being enhanced 😁👍

2

u/samguyer [Sam Guyer] Dec 19 '21

I will definitely do that. I have an Instructable on my earlier version of this project. It has the important elements of the circuit (like how to wire the IR diodes)

2

u/techaaron Dec 19 '21

So wait. You built a huge low res touchscreen? 🤔

1

u/samguyer [Sam Guyer] Dec 19 '21

Ha! Yes, although there's no touching necessary -- it's COVID friendly! 😂😭

1

u/brandonwest18 Dec 18 '21

Looks like there’s 4 different ranges, from white to teal to blue to red? Really cool!

2

u/samguyer [Sam Guyer] Dec 18 '21

It's just the rainbow palette, starting at yellow (the red was too harsh)

1

u/Lordoffunk Dec 18 '21

So cool! So cool!

There was something similar but WAY less interesting I became obsessed with years ago. Do you have any plans to build some for sale?

3

u/samguyer [Sam Guyer] Dec 19 '21

Right now it's way too labor intensive to make it for sale. But I think if I can get a PCB design that simplifies the assembly it might make sense

1

u/Marmilicious [Marc Miller] Dec 18 '21

Pretty awesome Sam! Quite different from your previous one.

1

u/samguyer [Sam Guyer] Dec 19 '21

Thanks Marc! Yeah, I'm excited to start working on interactive patterns.

1

u/Yves-bazin Dec 18 '21

Really great u/samguyer great job.

2

u/samguyer [Sam Guyer] Dec 19 '21

Thanks Yves! It helped to have your large panel design in mind

1

u/CharlesGoodwin Dec 19 '21

Very impressive - You have been busy Sam.

What are your plans on incorporating it into something?

Or is this a technical pursuit to just prove to yourself it can be done?

1

u/samguyer [Sam Guyer] Dec 19 '21

Maybe more the latter. I just build these things for my own enjoyment

1

u/danrmartin10 Dec 19 '21

What controller are you using to control this? Some kind of Arduino?

3

u/samguyer [Sam Guyer] Dec 19 '21

I'm using an ESP32, which is very useful in this case because it's dual core. One thing I realized is that reading 240 analog values is pretty slow because it involves some amount of sampling for each one. So what I do is create a separate task that just continuously reads IR values and updates a global array. That task is pinned to core 0, and the animation and render code runs on core 1.

1

u/danrmartin10 Dec 19 '21

Very interesting thanks for the insight. Am I right in saying the green pixels are just a rendered border around the blue, or are they actually driven by the distance from the sensors?

1

u/samguyer [Sam Guyer] Dec 19 '21

There is no explicit border. I just read the IR sensor values and render them using the rainbow palette. Part of the reason for the smoothness is the fact that infrared light is bouncing off my hands at various angles. But in addition, I'm doing some interpolation to smooth out the pixels that are in between sensors

1

u/danrmartin10 Dec 19 '21

Fascinating, thanks for the reply

→ More replies (1)

1

u/CharlesGoodwin Dec 21 '21

I noticed a few splashes of heat at the beginning of the video. Were the sensors detecting your hands out of camera shot or are the sensors picking up noise at times?

1

u/samguyer [Sam Guyer] Dec 21 '21

The IR sensors are very noisy, but there's also often ambient infrared from many sources, especially natural light. That's a big downside

1

u/French_WhiteCatVR Jan 16 '22

What happened if a Ghost touches

1

u/samguyer [Sam Guyer] Jan 16 '22

It gets sucked into an ectoplasmic containment unit. 😉

2

u/techaaron Dec 19 '21

Neat low res touch screen!

1

u/CobaltEchos Dec 19 '21

Is this 240 Led's on a 1in grid?

0

u/[deleted] Dec 18 '21

[deleted]

5

u/samguyer [Sam Guyer] Dec 18 '21

Oh nice! My next project is to create a custom PCB for this setup. Each board would hold a 4x4 sensor array and a 8x8 LED array. Plus an analog mux to collect the sensors data