Wireless communication to Arduino

Hello,

I am trying to built some sort of feedback system, where students for example or just people from the audience have to rate a presentation: The audience sees a question and they are supposed to have some sort of device in their hand which they can use to vote. Of course there are tons of ways to do it and thats what I am trying to figure out: which is the best. I started off by using the common nRF24L01+ module. One Arduino acts as the receiver and "processes" the data, the other ones are the handheld devices, which send the data. I would like, however, to only use one Arduino that receives all the data and not have an Arduino in every handheld device... I wish to have like three or four buttons on my transmitter. The receiving Arduino then is supposed to print out the results via processing.

I know now how to do all this with having Arduinos in the transmitter, but how can I achieve this without them? And do you think the nRF24L01+ is the right module to do this? I would be grateful for any ideas!

Is the not wanting an arduino in every device due to cost, size, power consumption or something else? Almost every gadget you use today has some sort of microcontroller in it. It's just so small that you don't know it's even there.

I pretty sure something like the xbee (expensive) can function standalone to transmit the status of switch inputs. Perhaps the nRF24L01+ has something similar?

Are these things battery powered? Who has the job of changing, or charging a 100 batteries?

Anything that is portable will get stolen. if it's tethered then why not use a wired connection for data and power?

You are going to need some sort of microprocessor in each hand held device.

An ESP8266 (such as the Wemos D1 or similar) might be an economic solution as it includes a microprocessor that can be programmed using the Arduino IDE and WiFi capability. You could use a laptop as a small server to which the hand-units could communicate via a WiFi router (or is the term Access Point?).

Or if you really need to save money just use a bare ESP8266 with a few external components.

I have been using nRF24s for remote control for model trains with an Atmega 328 as the brains. They are not expensive but they are rather tedious to construct.

...R

Thanks for the replies.

mikb55: Is the not wanting an arduino in every device due to cost, size, power consumption or something else? Almost every gadget you use today has some sort of microcontroller in it. It's just so small that you don't know it's even there.

I realize I was not detailed enough and I kind of sound stupid. It's mainly about size. But of course all the mentioned aspects are somewhat important. Power consumption I'd say is the least important though.

mikb55: I pretty sure something like the xbee (expensive) can function standalone to transmit the status of switch inputs. Perhaps the nRF24L01+ has something similar?

No, as far as I am concerned the nRF24L01+ does not have those capabilities. But as Robin_S also suggested:

Robin2: An ESP8266 (such as the Wemos D1 or similar) might be an economic solution as it includes a microprocessor that can be programmed using the Arduino IDE and WiFi capability. You could use a laptop as a small server to which the hand-units could communicate via a WiFi router (or is the term Access Point?).

I was thinking about those too.

mikb55: Are these things battery powered? Who has the job of changing, or charging a 100 batteries?

Anything that is portable will get stolen. if it's tethered then why not use a wired connection for data and power?

I do not have to be able to actually use it many times and I have to use wireless communication. And I also do have to use an Arduino at some point.

How many people will using the system, and will they all be pushing the buttons at the same time? If so, you will need to handle the issue of data loss caused by multiple transmissions .

If it only has to signify its presence, I would have thought the NRF24 could do that without an Arduino, I'm sure you could do it with bare bluetooth. But some of those bare-essentials ESP8266s have their own intelligence and and cost about the same anyway. The real cost is surely going to be in the packaging.

Another thing you need to be careful about is re-inventing the wheel. It's the sort of thing that would be a lot cheaper to buy than make.

Nick_Pyner: If it only has to signify its presence, I would have thought the NRF24 could do that without an Arduino,

An nRF24 can't do anything without a microprocessor.

...R

Nick_Pyner: I'm sure you could do it with bare bluetooth.

You mean just a simple bluetooth module like an Hm-10 or Hm-06 (I have them here...). How would it then be possible to do this?

Nick_Pyner: Another thing you need to be careful about is re-inventing the wheel. It's the sort of thing that would be a lot cheaper to buy than make.

Thats what I thought too and why I was thinking about buying some sort of wireless handheld transmitter but they are not as cheap as I thought. Further, I am supposed to experiment and actually try these things by myself.

mauried: How many people will using the system, and will they all be pushing the buttons at the same time? If so, you will need to handle the issue of data loss caused by multiple transmissions .

At first its supposed to be just two or three at the same time, but for sure I have been thinking about this too. My first idea was to have the main Arduino (the receiving one) ask the handheld transmitters to send there data, thus only one signal is being sent at a time - could that work?

And is there any other cheaper and smaller microcontroller than the Arduino nano I could use?

Thanks for all the replies.

Not quite. HM-10 and HC-06 will not work together. I was thinking a swag of HC-06, each with a different identity, and being polled being polled by an HC-05. I don't know much about the HM-10, but I suspect a group of those will be even more suitable. In both instances the base justs asks "are you there?", signal or silence, and moves on to the next one.

I would not have thought the Nano was a good choice. The most you would want is a 3.3v Pro Mini, and you would most likely use something really basic.

Now that it has been mentioned this is probably a classic case for BLE units sending out short messages - I think it is what the concept was created for. But I don’t know how to do it :slight_smile:

…R