Using one Master and two slave bluetooth Arduino devices?

Hello,
I would like to know if having three (or four as explained later) Arduino boards communicating in a Slave/Master role.
The project would include using an Arduino uno to receive data from two other Arduinos via blue-tooth. One Board would measure accelerometer data from a rotating bar and send it to the Master. Another setup would use two Arduinos, one to drive a motor using a shield and potentiometer, and another to receive data from a IR sensor and accelerometer of a slider crank mechanism with varying link lengths. Then a bluetooth module would transmit data to the Master.
My questions are, would this be over kill (using two boards for the multiple sensor set up)? are there any limitations in terms of transmitting and receiving so much data?
Which forum should I look into to find more info on code, circuit set up and other things I could be missing.

List of devices:

  1. Arduino uno (qty 4)
  2. Arduino motor shield rev3 (qty1)
  3. Bluetooth module hc 05 (qty 4)
  4. bread boards (qty 2)
  5. 10kohm potentiometer (qty 1)
  6. Dc motor with encoder attached (qty 1)
  7. 20 or 22 gauge wires (qty tbd)
  8. triple axis adafruit accelerometer MMA 8451 (qty 2)
  9. Sharp IR sensor GP2Y0A21YK0F (qty 1)
  10. resistors (qty tbd as well as their resistance)

Thank you for your time, have a nice day

Hello, and welcome.

What exactly are you trying to do? A description of your project makes it much easier to help.

AFAIK Bluetooth devices normally pair on a 1 to 1 basis so I do not think of them as suitable for a one-to-many situation. Perhaps the nRF24L01+ modules would be more suitable? Have a look at this Simple nRF24L01+ Tutorial.

...R

My project consists of measuring the properties of a slider crank mechanism with a motor attached to a disk, which will then drive the bars necessary to move the slider in a linear motion.
Hence the motor, accelerometer (to measure the velocity of a moving bar and certain points), and IR sensor (for slider movement)

The other apparatus is a simple bar rotating, no motor needed as it will be manually turned. which will then measure the corresponding accelerometer. Simple but a necessary principle in kinematics.

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I have a feeling that you could do the whole job with a single Arduino - perhaps a Mega if you need the extra I/O pins. But I can’t be certain based on your description so far.

The only reasons I can think of for using more than one Arduino are

{A} they need to be some distance apart
{B} one on its own could not perform fast enough.

If you do need wireless communication between the Arduinos I think the nRF24 modules would be much more suitable than Bluetooth.

…R

I'm sorry. I left out a very important aspect that both apparatuses will be separate.
They will use the Master arduino I was planning on using to receive data from both blue-tooth apparatuses.

The slider crank will have its own power source from a wall wart.
The Master will be connected to a computer.
and the Simple moving bar will also have a power source. Still figuring out if a battery will be enough.

The Master will then output the data.
But the more I think about it, the more I realize that maybe I could use a bluetooth adapter on the computer and cut out the middle man.

There's still some ways to go, but I would like to know just how realistic this is.

martinilmarciano214:
But the more I think about it, the more I realize that maybe I could use a bluetooth adapter on the computer and cut out the middle man.

That sounds like moving the problem rather than fixing it, and may even make the situation worse. It is possible to have a master HC-05 communicate with several slaves but it means that the master has to be reconfigured every time you want to talk to a different slave, and about the only good reasons for doing this are that you have the modules to hand and are familiar with them, neither of which seem likely in your case.

As noted above, you would probably be better off using an NRF24 network between the various Arduinos, which is designed for that sort of thing, and one Bluetooth to talk to the outside world, if you need to. NRFs have about the same price and performance as HC-05.

Bluetooth as a standard allows for up to 7 slaves connected to one master. As far as I know this feature is not supported by the HC-05 or HC-06 module, also I understand this to be 7 independent connections, so no broadcast from master to all slaves at the same time.

What about two Masters and two slaves?
For example,
Master 1 will correspond to Slider Crank mechanism and be referred to (in paper not in code) as Slave 1
Similarly, for the simple bar. Master 2 will correspond to that blue-tooth module titled Slave 2.

That should work - it's quite feasible to connect two HC-05 modules to one Arduino, as long as you can get enough Serial or soft serial ports.

So the Mega would be my option, since it has multiple serial ports

martinilmarciano214:
So the Mega would be my option, since it has multiple serial ports

I'm curious to know why you seem fixated on Bluetooth when nRF4s would be simpler to implement. It would be different if you were already a Bluetooth expert but from your questions I infer that you are not.

...R

The Project I am working on has a selective Vendor list. And the NRF24l01 is not on any of those vendors, instead it’s the NRF51822, which looks a whole lot different than what you posted. So Hc-05 is my only option really.

I should really give this info at first. I’m sorry, my brain was burnt out when I posted this.

martinilmarciano214:
The Project I am working on has a selective Vendor list. And the NRF24l01 is not on any of those vendors, instead it’s the NRF51822, which looks a whole lot different than what you posted. So Hc-05 is my only option really.

I should really give this info at first. I’m sorry, my brain was burnt out when I posted this.

As far as I can see the NRF51822 is BLE.

Maybe your vendors sell 433MHz transceivers such as the HC12

…R

The word "Newbie" is really overrating my ability.

I'm so sorry for wasting your time.
After a quick search of 433 mhz receivers on a vendor site, I look at the other RF models and see the fabled nrf24l01 model. This whole time I was searching for "Bluetooth nrf24l01" modules and nothing except the 51822.

Now I see https://www.robotshop.com/en/24g-transceiver-nrf24l01p-module.html

Now if you'll excuse me, I'll go look at your handy guide.

martinilmarciano214:
I'm so sorry for wasting your time.

No problem. Glad you are making progress.

...R