IoT-Station with wireless sensors "ESP8266 vs NRF24L01"

Thread Starter

icecreamman

Joined Jan 23, 2019
3
Hi AAC-Community!

I'm excited to talk to you about my new little project. It's sound simple but I think it is a good starting point. I'm working on a IoT-Station to measure temperature and humidity with wireless sensors and display the data on the smartphone.

Following you will find the specific requirements that I am looking for.

Sensor:
  • Measurement sensor + RF-Transmitter + uC
  • BME280
  • Stand-Alone operation over months (Coin-Cell)
  • Send 1 data package per hour
  • Small size (miniature sensor, as small as possible)
  • range <10m (indoor)
Gateway (if necessary) / Visualization on IoT-App:
  • show measurement data on a smartphone (history graphs, notifications etc.)
  • use a gateway to collect data and send them to an IoT-Service
  • Gateway: Raspberry Pi (preferred) or Arduino
  • IoT-Service: Blynk
  • multiple sensors

I already evaluated two possible RF-Modules. Please find below my pros and cons:

ESP8266:
+ no gateway necessary, direct connection to Blynk
- high power consumption but probably not possible to run stand-alone

NRF24L01:
+ low power consumption (made for coin-cell and long term applications)
- Gateway necessary to send data to smartphone


So far I liked the version with the ESP8266 chip because of the direct connection to Blynk (no gateway) but due to the power consumption I don't think it is possible to run them stand-alone in small size over months. Although I saw some workarounds with the ESP8266.
Therefore I think I go with the NRF24L01 module and an Arduino. I thought about using a Raspberry Pi to collect the data and send them to Blynk.

So these are actually my current thoughts and below also some questions I'm working on it at the moment. I'm excited to hear your feedback.

Would it be possible to setup an ESP8266 for my requirements concerning power consumption?
Does anybody has some experience with Blynk? Any advice?
And would it make sense to use a Raspberry Pi as a gateway with the idea to store the data history locally and send them to blynk.

Thank you for reading. Any kind of comments are welcome!
cheers
 
Why wouldn't you consider BLE? N/M but welcome to the site.

I have had some success using a RTC alarm to turn on power periodically to a board (including an ESP8266) and, after doing something, turn itself off until the next period. So, once an hour would be easy. But, you are not going to be able to use a coin cell battery or get months. Maybe, something like that with a set of four AA's

You can see a somewhat sloppy write up of the project here (and you have to log in there). That one used an MCP79410 RTC.

Here you can see the same idea (different application) using the more common (and preferable, to me) DS3231 with more information about programming as well as a couple of sample circuits.

Hope this helps.
 
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Thread Starter

icecreamman

Joined Jan 23, 2019
3
Thank you for your comments and wishes!

That sound actually like a smart workaround with the RTC but I don't think this will fit to my requirements (small size, operation over months).

After more research I don't think I will be able to build the sensor with a ESP chip due to power consumption. Therefore I think I go with an NRF module. I didn't evaluate BLE so far but it could be an option. Any experience you can share comparing with an NRF module?
 
Thank you for your comments and wishes!

That sound actually like a smart workaround with the RTC but I don't think this will fit to my requirements (small size, operation over months).

After more research I don't think I will be able to build the sensor with a ESP chip due to power consumption. Therefore I think I go with an NRF module. I didn't evaluate BLE so far but it could be an option. Any experience you can share comparing with an NRF module?
Your most welcome....especially if you follow up and also tell other folks what you ended up doing and how it is working out.

I have very little experience with the NRF24L01. I do have a few and have tested them out. After getting them, however, I started to get into ESP8266 (and now ESP32) and others and have always found them to be easier/better and I haven't had any need to look further into them.

I think that this part of your specifications are going to be an issue, but not necessarily an insurmountable one:

Measurement sensor + RF-Transmitter + uC
So, the low power of the NRF24L01 is clear, but you also have to have the low power of the uc and it has to be capable of reading the sensor and transmitting the information to another computer.

I am interested in knowing what you come up with.

Edited to add: As for the BLE, yes that is definitely feasible. But, I would suggest that you consider using a BLE "Beacon" that is sending the BME information in the advertisement. Now, you don't need a gateway at all, you just need to listening for the advertisement. I am doing something like that here in a couple of ways with temp and humidity - including using these.
 

Thread Starter

icecreamman

Joined Jan 23, 2019
3
Thank you for your inputs.

I ordered some NRF24L01+ as well as ESP32 (for BLE communication) modules to test both options in the next step. I'll let you know the results as soon as I have the first measurements done.
 

nb99

Joined Feb 28, 2011
5
Use an Arduino ProMini with nRF24L01 as your sensor node. Chop the power Led off the ProMini, and change the 3v3 regulator to an mcp1700 (or just use the raw 3v button battery), and you will have sleep current of the order of 10 uA. ( and plenty of ADC and digital i/ps for sensors)
Use an ESP with an nRF24L01 attached as the 'base station' - it receives the data from the sensor nodes, and communicates with Blynk. A much lighter solution (all round) than an RPi.
( I also have a simple 433Mhz transmitter hung off the ESP, which gives control of 433Mhz mains power switches from Blynk)
 
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