Length or how far ultrasonic sensor can be allowed from Arduino or no limit?

I'm a very beginner with Arduino. My concern is there is any distance or length specification or restrictions for the io ports. I mean if my sensors (ultrasonic sensor) is possible to keep around 20 meters away from Arduino. Is that possible to implement or is there is any issue on that. Also I need to illuminate an LED bar graph strip which is also about 30m away from Arduino. So both io are far from the controller. Is that ok.

Requesting any kind of support

You'll have problems at those distances with fast changing signals. The bar graph should be ok as the eye
can't see such rapid changes, but the ultrasonic pulses might have problems. If you have some cable you
can try it out and see. Voltage drop in the supply may also be an issue, depending on the resistance
of the cabling and the current taken by the remote device.

What I have done in these cases is to use a differential line receiver and transmitter.
At the sending end use a AM26LS31 driver. Then connect the two wires per signal at the far end to a AM26LS32A receiver. You get four drivers per package. You also need a common ground signal but only one for all the drivers and receivers.

I have found this gives a very solid signal even at high data rates.

I don't have an answer to your question as asked but you might consider a remote board communicating
back to the console via a UART. An Arduino Mini Pro is pretty cheap and small.

Grumpy_Mike:
What I have done in these cases is to use a differential line receiver and transmitter.
At the sending end use a AM26LS31 driver. Then connect the two wires per signal at the far end to a AM26LS32A receiver. You get four drivers per package. You also need a common ground signal but only one for all the drivers and receivers.

I have found this gives a very solid signal even at high data rates.

Thanks a lot for that suggestion. That's something I will try. But it needs two Arduino boards at all end points. Isn't it? I thought about doing all with single board.

JohnRob:
I don't have an answer to your question as asked but you might consider a remote board communicating
back to the console via a UART. An Arduino Mini Pro is pretty cheap and small.

You mean to have separate Arduino at each end they can communicate each other, isn't it? If so length cannot be an issue? Sorry am very recently started with electronics as a hobbyist

But it needs two Arduino boards at all end points. Isn't it?

No. Why do you think that?

In this situation I would use promini with NRF24L01+ modules that can wirelessly send the signals and more to the various locations. It's more advanced in the programming area, but a steady learning curve as a bonus for you! :slight_smile:

There is a lot of info on this forum about such systems. Start as simple as possible and slowly build it up.

Grumpy_Mike:
No. Why do you think that?

Sorry that was a typo I mentioned as TWO boards at each end points... I mean it needs an Arduino at all points. Like 1 for relay, 1 for LED and 1 for sensor. And all these to communicate by some sort of wireless or wired way (By using RS485.. Never tried.. Stackoverflow gives this info)

skywatch:
In this situation I would use promini with NRF24L01+ modules that can wirelessly send the signals and more to the various locations. It's more advanced in the programming area, but a steady learning curve as a bonus for you! :slight_smile:

There is a lot of info on this forum about such systems. Start as simple as possible and slowly build it up.

Thats really a great information.. I ordered the same just now.. Thanks bro for sharing that info..

You are welcome.

I think it is a good solution for your problem. But like I said, start small with ping pong sketch from the tmrh library and slowly you will get there......

But be prepared to loose some hair in the process! :wink:

sforsandeep:
Sorry that was a typo I mentioned as TWO boards at each end points... I mean it needs an Arduino at all points. Like 1 for relay, 1 for LED and 1 for sensor.

No you only need one Arduino using the AM26LS31 driver and AM26LS32A receiver solution.

For each signal you want to send over a long distance you need a single driver and single receiver. Their are four drivers / receivers in each package. So for driving a relay you need a quarter of an AM26LS31 at the signal end and a quarter of a AM26LS32A at the receiving end. This applies to LEDs as well. What you will need is a voltage supply at the receiving end to power the LED or relay. This can be sent down the wires at something like 12V and regulated at the receiving end with a fixed voltage regulator.