Hi, I have a project where I need to connect a very large amount of IR receiver and emission (a few hundred).
I don't think it's feasible in Arduino, what are your thought ? If it's feasible, how ? And if not, how can I do that other than Arduino.
Thanks !
IR receivers like for IR remote controls? Or sensors for IR light?
Please take i little time and better describe your project. So far pretty ambiguous.
Read the forum guidelines to get an idea of the information we need.
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Sorry, that was the name on my box ^^'
I mean sensors for IR lights.
What I want is to use the IR emission (IR led) to find if someone is pressing on the screen (plexiglass) and get this information with the sensors.
In summary, creating a touch screen using optical technology.
Are you looking for reflections or for transmission of IR? Better test your material before continuing to design your project.
So the signal from each of the individual sensors is an analog signal?
Something like a "Touch Frame" ?
Google it.
Leo..
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Yea exactly like a Touch Frame it just that it cost less to create the touch frame myself than to buy it.
And even if I use the touch frame directly, I still have the problem that I need a lot of them, so I will not have enough pin on my Arduino.
And I wanted to use IR for the touch frame because I want the user to use it without his body directly like a shoe or glove or a stick or anything else.
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To make it work, you would turn on one IR emitter on the X axis and one on the Y, so two at a time (a pair). These LED pairs could be put into a 16x16 array for a total of 256 emitters for each axis.
If you use a 16 channel LED driver with serial inputs and a 16 channel shift register, those 512 LED could be controlled with as little as 4 wires.
However, do you think you could wire up 512 LEDs, that would be 1024 connections to be made.
No, I would just put one IR emitter because I just to know if someone touch the screen, I don't need to know where he touches the screen. But yea in the end I would need like 500 IR emitter and 500 IR receiver (one pair for each screen and like 500 screens)
The problem is that I don't think Arduino I built for that…
500 screens, that's a whole different story.
So basically you only need to look at 500 signals to see if a screen was touched or not.
You could use 32 I2C, 16 bit port expanders , so you would only need 2 arduino pins.
How far apart will the screens be?
Well, each screen will be maybe like 5 or 10 centimeters apart.
And with what you said, I can determine which screen will be touch ?
And the size of the screen?
I trying to an idea of how long the wires will be.
Depending on the physical arrangement, it might make more sense to use 5 Arduinos, 1 master and 4 slaves. Each slave would handle 128 screens and report to the master
Maybe like 20-30 centimeters square.
Yea the wire will be huge…
So in the end, the longest wire will be 10 meters
Now the problem is no longer "how can I connect 500 signals to an arduino" but "how do I supply power to 500 screens and send fast signals reliably of long cable runs.
It going to be a fairly complicated project and require a lot of upfront planning.
add: OIC, you making a stab at a "high" resolution IR screen. Never mind.
How do you get to 256! I know it's 16 * 16, but emitters in one side and detectors on the other would be a total of 32 emitters and 32 detectors to get a grid of 256 touch points working.
IR touch frames have been around forever. The firmware has to account for things like broken either emitter or detector, and for stuff like a wad of gum stuck on the screen.
There is vastly superior technology for touching these days. There was before, too, but there are circumstances where the IR is the way to go. But anything out if a box can get spendy, especially multiply by 500.
So good thing each is just a touched/not touched matter.
a7
well, I think using some servant and a master would be the best solution so I can separate the power and everything.
Well the first thing you need to do is draw a diagram with dimensions that shows the pyhsical layout of the 500 screens
What kind of screens do you touch with anything else and glove or stick?
If the screen is rigid, a piezo disk (acoustic pickup) can sense even a light tap. the usual project for those is as a door knock sensor.
With Arduino you can add chips like shift registers or (more $) port expanders to add pins. It's how 8x8x8 led cubes were made before WS28xx leds came out. There are Arduino Youtube videos showing long breadboards with chips and jumpers. If you see flat to the board jumpers, they're such a pain inserting and removing that you can turn the board upside down and whack it and none fall out. Those are wire wrap wire type jumpers, good for soldering on protoboard, the next step is PCBs.
You can make your own custom controllers... what is the time assembling those worth? Before Covid cheap Arduino Mini clones were less than $5 for 1. 100 of those may have cost $2 each. ATtiny85 DIP chips were $1 each if you bought 5.
Shop carefully and $ave!
These are just some considerations among the many options available. If you can budget 500 tablets? What can they do? Or by screen do you mean material with holes?
Just checking!
Really though, even a basic display needs power and stored or transmitted frames.
Ok, sorry for the delay, I was re-doing my research.
So I change and switch to vibration sensor instead of IR sensor. It's better, easier to use and use less PIN. But I still have a problem…
I calculate, and I will need to connect exactly 1800 components (450 Ă— (1 sensor + 1 green LED + 1 red LED + 1 yellow LED)), each taking 1 pin, so I need 1800 PIN.
I found the PCF8574/PCF8575… but with only 8 addresses I still need 900 PCF8574 or 450 PCF8575… which is impossible because I can only connect 8.
I don't really know how to do it…
I found that I can use something like a jumper to connect more PCF, but it is still like huge…
Do you have an idea ?