Bluz communicating with Arduino Uno


#1

Hi All,

I am trying to build a system that allows for a Bluz chip talk to an Arduino Uno. I want the Arduino to be the central hub, relaying data back and forth to the Bluz chip.
The trouble is that I don’t have any experience with using Bluetooth, and I am looking for any advice on what kinda chip I should wire to the Arduino, so that it is able to connect to the Bluz? Also any advice on the code needed?

Thank you :slightly_smiling:


#2

What kind of task is the Uno doing? Bluz can possibly perform all the tasks you need, so you may not need the Uno at all.

If for some reason that wouldn’t work, what kind of communication did you need between the two? The Uno is 5V and bluz is 3V3, so you would need to shift the voltage between them. If your communication is as simple as flipping a few GPIO’s then you can just use resistors. Or you can look into level shifters, there are many available. A little more detail may help define better what you would need.


#3

I would like to use the Bluz as a temperature reader in different areas of a room, in a stand by mood. Then have the Arduino call out to the Bluz every 30 mins to get a reading on the temperature.
If possible I would like to connect multiple Bluzs to the Arduino hub.

I know I can do this with a Photon and gateway, but I want to do it with an Arduino.


#4

Ah, sorry, I misunderstood. So you would like to talk BLE between bluz and Arduino, correct?

You would need a BLE shield that can operate in central mode. I don’t know of any off-hand, but some quick googling gave me this option: http://www.seeedstudio.com/wiki/Seeed_BLE_Shield_v1

With bluz in its current form, though, this wouldn’t work. Currently if bluz can’t get a connection to the Particle cloud, it will disconnect from the central. We are going to go back and change this as part of the first release and add API’s to allow bluz to talk to any other BLE device. But for the moment, the BLE connection is mainly used to talk to the Particle cloud and that’s about it.

In your topology, the Arduino wouldn’t allow bluz to connect to the Particle cloud. As I mentioned, that will be allowed in the next release, but it also means that your boards can’t get firmware updates. Using a gateway shied with a Photon would simplify this as you could have both firmware updates and local Arduino-style control for whatever it is you want the Uno to do. Just a thought.


#5

Hmmm. Ok thank you Eric for the insight.
So currently it would be better to have the Photon and Gateway set up with the Bluz to collect the data. Push it to a server and then push it to the Arduino to preform the action. Seems like the long way round, but it might work.
Do you know of an examples of the gateway being used with multiple Bluz chips (Code and SetUp)?
Thank you and I appreciate the help.


#6

Is there a particular reason you need to use an Uno? The gateway with a Photon should be able to do the same thing. I agree it is repetitive to have the Arduino and the Gateway in there.

The gateway shield will allow 8 devices to connect, so you shouldn’t have any concerns about quantity of devices (unless you need more than 8).


#7

I’m looking to build a system for monitoring multiple indoor plants for this challenge on Hackster. Thus the need for the Arduino. Honestly I would prefer to use the Particle ecosystem, but it will be an interesting challenge to use the Arduino.


#8

Ah, that makes sense.

I have an idea, but you may not like it :smile: The MKR1000 is just a WiFi board, I assume there are some Arduino-style commands to open ports and whatnot (I haven’t used it, though, so take that as my assumption). What I would do is turn that into a gateway. The majority of the logic for our gateway shield lives in the nrf51 chip, we pretty much just use the Photon as a dumb internet back-end that can open up TCP sockets for us. Then we simply send data to it through SPI and it forwards it to the TCP socket.

What you could do is translate the Photon sketch that we use for the gateway to the MKR1000, then pair it with our gateway shield and that becomes your gateway. Now you have the wonders of the Particle ecosystem but you are using an Arduino. As we already have the Photon sketch, I don’t think it would be too difficult. The wiring may be tricky, the MKR1000 almost certainly wouldn’t fit our current socket, but an adapter board would work (if you wanted to make a PCB) or you could just breadboard it with jumper wires.

Looking a little further, can you even buy the MKR1000 yet? It doesn’t appear to be available? I guess you could use the Yun in the same way, though it is terribly expensive. Perhaps a WiFi shield?

Also, I see this in the rules:

All submissions must include Windows 10 and Arduino.cc boards (only)

Not sure if that means you can ONLY use Arduino boards and no others, I suppose it could be read that way. If that is the case, then using bluz may not be allowed.


#9

Right now that seems a little out of my league, I only just started coding.
And now re-reading it you maybe right about not being able to use other chips. However, I can still build the first part of the system for the challenge and then once I understand a little more and have more time, I can add the Bluz and “gateway” to the system.
If it’s not to much to ask, how long would a Bluz last on a coin cell if it was to read the soil moister 24 times a day with one of these, rough estimate?


#10

I don’t know a lot about those sensors, but it depends a lot on how much current they draw. The amazon page just says <20mA, which is pretty high. You would certainly need a way to shut if off when not in use, drawing 20mA continuously on a coin cell battery would kill it in a few hours probably.

As for bluz itself, you could get months out of that type of situation if you tweak the parameters correctly. For instance, turn off the RGB LED, make sure no other peripherals are on (like UART, I2C, etc.) and then lower the connection interval as much as possible. We will add more and more ways to get longer and longer battery life in future releases, so this will become easier and easier to achieve.


#11

Thank you for the insight. I’m going to relook my approach, but may still go with the Photon gateway and Bluz. Next months budge problems. LOL
Thank you for all your help, and if you are interested in getting the Bluz into a hackathon, please let me know.