component list and overall project advice please

Projects General Guidance
1

Hey all, planning to start my second ever Arduino project (so still REALLY, REALLY, REALLY new to all of this) and have researched myself into a black hole :o

I have some bits left over from my other project and starter kit at my disposal, but am also more than willing to get different bits if it makes things easier or better. I am really just hoping for some advice and recommendations on putting together the right components to make my chances of succeeding at this project as high as I can get them!

So, the project is relatively straight forward, I want to experiment with an evacuated solar tube I have and various configurations of heat exchangers, etc. I want to attach a bunch of sensors and log the data and I really want to be able to send the data to the cloud and be able to publish it using a service like mydevices.com or freeboard.io... Any advice on a user friendly option here that is preferably free would be very much appreciated!

The list of sensors I'm planning to use initially are as follows, but I'm sure that I will be wanting to add more in the future as well as probably some relays.

Sensors:

2 thermocouples (to measure out going and incoming temps): I'm thinking type K like they have on sparkfun or adafruit.

  • Seems that I will require an amplifier for each thermocouple so I was thinking it might also be a good idea to use a MAX31850 1wire breakout board also found at adafruit.
  • Also appears that in order to use this amplifier I will need a level shifter from 5v to 3.3v so adafruit's BSS138 4 channel I2C-safe Bi-directional Logic Level Converter seems like what they recommend... one unit should be good for both amplifiers?

At least 1 (for now, probably will want to add one or two more in the future) DS18B20 temperature sensor (also one wire)

1 temp and humidity sensor... I have a DHT11, but might be worth upgrading to the DHT22?

1 LDR (photoresistor... want to measure light intensity... ie is it full sun? cloudy out? etc.)

Something to measure flow rate... looking for suggestions here please

Something to measure system pressure... looking for suggestions here also please

As for the hardware, I was hoping to maybe use a Nano that I have, with a wifi breakout board to send the sensor data to the cloud... There seems to be a lot of good info and tutorials out there on the ESP8266 so I was thinking of getting one of those, but it also seems like there are a lot of different configurations available, some which maybe wouldn't require the Nano at all?, some that come pre installed on a nano? This will be my first attempt at anything like this so I'm really in the dark here despite all the reading I've done and looking for the best Noob option... One post/blog/thread thing I read

indicated that the ESP8266 doesn't necessarily play nice with the Nano and the web host (cayenne from mydevices.com) that I was leaning towards... it seems like maybe he got his figured out, but it also seems like he knows what he's doing :confused:

Am I correct in understanding that the ESP8266 also requires 3.3v? And I could use the same level shifter for the thermocouple amplifiers for this or would I need a separate one? ie. one level shifter to work with all 3 devices?

If the Nano is not the best option, I also have a Mega, but I thought that seemed like it might be a bit of a waste on this project. Although, it would likely provide more flexibility for future additions and functionality? For the Mega, I have an Ethernet shield that I could also incorporate if needed.

I think that's about it... so in a nutshell, looking for advice on hardware and recommendations on how to most easily get sensor data to a neat cloud service like cayenne or freeboard or any other recommendations for a service like these... Also, I've been looking for and reading or watching as many tutorials as I can on similar projects, but if this rings a bell for someone, I'd appreciate any links you might have to other similar helpful tutorials!

Oh, just remembered one final question... this is one of several projects I hope to do and I would like to have them all be accessible from the web like this... is there any advantages or disadvantages to having each project directly and independently connect to the web vs connecting through a single gaetway device first?

Thanks for taking the time to read all this and any advice is very much appreciated!

Cheers,
Joe

2

so my initial post didn't get any love :frowning: maybe I asked too many questions? anyways, after doing a bunch more reading, I'm leaning towards abandoning the nano and just going with the adafruit feather HUZZAH, but i see that it only has one analog pin... Will i be shooting myself in the foot if i use that pin for my photoresistor? I think all the other sensors can use the digital pins? except I still haven't figured out what might be the best options for flow rate and system pressure if anyone has any suggestions :slight_smile:

Thanks,
Joe

3

I'd start with the already available controller(s) and additional parts, then pick one extension at a time and become familiar with it, before starting a more complex project.

I also prefer a big controller (Mega) for development, before choosing a smaller one for some dedicated stand-alone device.

An USB port requires the controller to run on 5V. If you want to use a couple of 3.3V devices, a Pro Mini may be a better choice, because it also can run on 3.3V. But consult the data sheet before a buy, because there exist 3.3V, 5V and versions which support both supply voltages (mine do). Also consider to use a separate 3.3V power supply, because some modules (for RF transmission...) need more current than the on-board 3.3V regulator can supply.

4

Thanks DrDiettrich! the reason I've been debating about the nano vs huzzah feather vs sparkfun thing vs the billion other options out there is because I know I want to be able to connect via wifi, and this will a first for me (if I can get it to work), and will also require me to buy something as I don't currently have a wifi shield or anything like that. So as I'm looking at buying the esp8266 (or equivalent), it seems the easiest solution might just be to get something integrated like the huzzah or the thing.

So I figured since I had to buy a wifi part no matter what, and I'm expecting this part of the project to be one of the biggest challenges, it might be best to figure out which component I should use for this as it could be the foundation for everything else...

Also, since I'm very new to all of this, ease of use and set up is pretty key if I'm going to have any chance at success.

What I'd really like to do is figure out what controller I should use and get 1 sensor hooked up and displaying data on the web. I think from here, evolving to include additional sensors shouldn't be too bad... I hope :slight_smile:

I was just looking at this pressure transducer on Ebay...

seems like it might work for me, but requires 5v... which makes me wonder if one is better off using a 5v controller and level shifter for 3.3v extensions? (I'm guessing that's the right usage of that term?) or is a level shifter capable of shifting equally well from 3.3 to 5v?

Thanks,
Joe