using esp8266 without Microcontroller

Projects General Guidance
1

Hey all,
I'm now done with my brakes (thank goodness) and ready to focus on my project once again. I decided since I got my Wifi Module in the mail recently, it was time to step into the age of IoT to see what I can do.

Project Details

  • Project: IoT Temp and RH Data Logger
  • Objectives: I'd like to record the temp and RH every 30 seconds, once the sensor takes the reading I would like it to write the info to an SD card as well as have it accessible online

Components available for use

I linked to the product page as well as the data sheet for the ESP module I'm using.
I was looking over the page and noticed this on the 'product details' section

This is the ultimate Internet of Things board. Easy to connect with and powerful enough to pull sensor data off without the use of a dedicated mircocontroller. A wealth of information and huge community has made this one of the best options to make your toaster tweet to the world, update your pianos Facebook page, automate your juicer, turn your lights off or on, the options are endless!

So my question is, can I use the ESP8266 without the Uno in this way?

On a side note, I was considering using ThingSpeak to access things online, is this platform fairly beginner friendly?

2

yes. the ESP8266 is a stand-alone micro-controller and can be used.

3

The ESP8266 is a powerful microcontroller, on its own, with built in WiFi capability. You can program an ESP8266 using the Arduino IDE after installing the ESP Arduino core.

Here you will find documentation on the core.

A good place to start is the ESP 8266 Beginners Guide.

I built a weather station that has temperature, humidity, barometric pressure, wind speed and direction and a rain gauge with just an ESP8266 as the controller, so your project is definitely doable.

I don't know about Thingspeak. My weather station has a web page server that I access from my home WiFi.

4

what do you want to do with that esp-12?
You should buy an esp8266 dev board like NodeMcu or Wemos. it has USB, auto-reset, boot config circuits.

https://tttapa.github.io/ESP8266/Chap01%20-%20ESP8266.html

I saw somewhere mentioning a problem with DHT-22 on esp8266.

5

You should buy an esp8266 dev board like NodeMcu or Wemos. it has USB, auto-reset, boot config circuits.

Agreed. You will make the process of learning about the wifi world a whole lot easier by using one of the development boards instead of the bare module.

6

Juraj:
what do you want to do with that esp-12?
You should buy an esp8266 dev board like NodeMcu or Wemos. it has USB, auto-reset, boot config circuits.

https://tttapa.github.io/ESP8266/Chap01%20-%20ESP8266.html

I saw somewhere mentioning a problem with DHT-22 on esp8266.

I'm trying to send readings from a temp/rh sensor to something like Thingspeak. I also have a DS18B20 Temp sensor, Maybe I should start with that.
I was actually looking at the NodeMCU and Wemos D1 awhile ago, I found a Wemos for a decent price. I really only ended up getting the ESP module bc it was cheap and I was already ordering a few LED's anyway.

cattledog:
Agreed. You will make the process of learning about the wifi world a whole lot easier by using one of the development boards instead of the bare module.

Thanks, Hopefully I'll be able to get a NodeMCU or Wemos before long. Maybe I'll take advantage of some Black Friday Sales

7

the ESP-12 you linked has the micrcorprocessor and the pins to do what you want.
however, it does not have all the supporting devices that the WEMOS D1 mini or pro-mini have

to use the ESP-12, and there is no reason you cannot use it, but you need to deliver a power supply for the board. 3.3v with enough for your project.

also , you need to program it. this can be done with an Arduino board that has the USB connection.
and I would suggest that your first programming is to make it OTA programmable. this allows you to upload programs wirelessly eliminating the need for a USB connection.

===========
but your first post seemed to be asking if you can use an Arduino and an ESP board as an add-on board.
yes, you can do that too. you can use the ESP-12 and control it with an UNO or NANO or some such.

by the way, a WEMOS D1 MINI can cost less than the ESP-12 you linked.

if you are looking to save a few $$ the SD card might be optional. if you upload to the WEB, you might be able to retrieve your data from there until you find you must have it on your PC.

I have never looked to see if you can upload data over your home WiFi to a spreadsheet on your PC, but it seems possible.

Another way might be to store data in a file on the WEMOS and then retrieve that file.

Just thinking outside of the box here.

My main point is that if you have any ESP and any Arduino* and any temperature sensor, you should be able to get most of what you want right away.

/*
I use the word ARDUINO as any micro-controller that is programmed with the Arduino IDE and able to easily share programs and libraries with a variety of other micro-contollers. most of us think of the UNO when we say Arduino, and have to name the board, mega. teensy, nodeMCU, etc, but in a broad sense, they are all "Arduino's"
*/

As for temperature sensors, there are lots and lots of options.
some are digital, self contained measuring, then sending the readings back to your Arduino with serial information.
thinks like the DS18B20 and the BMx280 and the DHT.xx/AM2303 family are all digitally addressed.
usually, you use a library to reduce your program size.

there are also analog options.
Thermistors are temperature sensitive resistors, use one analog pin to read one temperature
LM34/35/ family (some F some C ) are analog and very sensitive
RTD's are simply some metals that are temperature sensitive, also use one analog port per device

You can use an op-amp and a diode, if you are so inclined. the PN junction is temperature sensitive.
much more work though.

Thermocouples are almost always used with a transmitter board. you can get them as analog sensors, or digital sensors. but Thermocouples are for very high temperatures. some can read just over 2,000 C.
but room temperature is not a good application. hard to resolve 1 degC, not good for fractions of a degree.

8
  • ESP8266 wifi module breakout board
  • Breadboard and Dupont wires

That's also a problem. The board's pins do not have the same spacing as a breadboard. Another reason to get a Wemos mini!

have a look at my sensors here.

9

You could also use an ESP32 based board, e.g. Wemos D32. This board has the advantage that you can directly connect a Lipo battery and also charge it over the board (if you would want to use your device battery powered). The ESP32 is a little more powerful than the ESP8266 and the sleep mode is better, so it can run longer on battery and it has bluetooth if you would ever need this. It is a little more expensive, but still really affordable and worth its money in my opinion.
If you want your values available online you could use the IFTTT webhooks to write it directly to a Google sheet. I find that really convenient for easy data storage.

10

Thank you for such a detailed answer.

dave-in-nj:
the ESP-12 you linked has the micrcorprocessor and the pins to do what you want.
however, it does not have all the supporting devices that the WEMOS D1 mini or pro-mini have

to use the ESP-12, and there is no reason you cannot use it, but you need to deliver a power supply for the board. 3.3v with enough for your project.

Yeah I'm thinking I'm going to go with a Wemos or NodeMCU. It'll be a week or so before I can get one though. I'll be making multiples of these so the easier the process, the better.

dave-in-nj:
also , you need to program it. this can be done with an Arduino board that has the USB connection.
and I would suggest that your first programming is to make it OTA programmable. this allows you to upload programs wirelessly eliminating the need for a USB connection.

I've never heard of OTA programming, doing a google search right meow. I'm glad to hear it can be programmed using an arduino board, I figured I'd have to get a serial to USB cable before using it.

dave-in-nj:
but your first post seemed to be asking if you can use an Arduino and an ESP board as an add-on board.
yes, you can do that too. you can use the ESP-12 and control it with an UNO or NANO or some such.

by the way, a WEMOS D1 MINI can cost less than the ESP-12 you linked.

dave-in-nj:
if you are looking to save a few $$ the SD card might be optional. if you upload to the WEB, you might be able to retrieve your data from there until you find you must have it on your PC.

I have never looked to see if you can upload data over your home WiFi to a spreadsheet on your PC, but it seems possible.

Another way might be to store data in a file on the WEMOS and then retrieve that file.

Just thinking outside of the box here.

My main point is that if you have any ESP and any Arduino* and any temperature sensor, you should be able to get most of what you want right away.

you're right, I suppose storing the info on an SD card would be redundant. When I first started the project I didn't plan on Wifi being an option, but now I may not need to bother with the SD module.

dave-in-nj:
As for temperature sensors, there are lots and lots of options.
some are digital, self contained measuring, then sending the readings back to your Arduino with serial information.
thinks like the DS18B20 and the BMx280 and the DHT.xx/AM2303 family are all digitally addressed.
usually, you use a library to reduce your program size.

ahh yes, libraries. They've given me as much trouble as anything when it comes to coding.

dave-in-nj:
there are also analog options.
Thermistors are temperature sensitive resistors, use one analog pin to read one temperature
LM34/35/ family (some F some C ) are analog and very sensitive
RTD's are simply some metals that are temperature sensitive, also use one analog port per device

I know a little bit about TDR materials from my vaping days, I played with Temp control for awhile using SS (or sometimes Ti) wire. So you think a TMP36 or LM35 would be a better bet than the DHT22? If I have to sacrifice a bit of accuracy for simplicity, It may be worth it, as long as they're reliable.

dave-in-nj:
You can use an op-amp and a diode, if you are so inclined. the PN junction is temperature sensitive.
much more work though.

I may have to look into that, It wouldn't be something I'd do in the long run, but it might be a fun experiment when I get snowed in this winter.

11

dave-in-nj:
As for temperature sensors, there are lots and lots of options.
some are digital, self contained measuring, then sending the readings back to your Arduino with serial information.
thinks like the DS18B20 and the BMx280 and the DHT.xx/AM2303 family are all digitally addressed.
usually, you use a library to reduce your program size.

there are also analog options.
Thermistors are temperature sensitive resistors, use one analog pin to read one temperature
LM34/35/ family (some F some C ) are analog and very sensitive
RTD's are simply some metals that are temperature sensitive, also use one analog port per device

so the NodeMCU Lua is on it's way, along with some thermistors. But I overlooked the humidity aspect of things. If I do away with the DHT22, then I'll have to add something to measure the Humidity. Any suggestions for a simple RH sensor? or should I go back to the DHT22 now that I've got the NodeMCU coming?

12

Measuring humidity is not simple (well, there's the wet/dry bulb method that you may implement with thermistors, but then an ESP8266 has only one analog input). Easiest is probably the BME280.

By the way, the DHT22 works just fine with a NodeMCU. Within the constraints of the sensor itself being able to "work fine". It's not a sensor that I deem suitable for permanent installations, unless you can be sure the humidity remains low (as in <80% or so). Those days of 99-100% are devastating the DHT22.

13

wvmarle:
By the way, the DHT22 works just fine with a NodeMCU. Within the constraints of the sensor itself being able to "work fine". It's not a sensor that I deem suitable for permanent installations, unless you can be sure the humidity remains low (as in <80% or so). Those days of 99-100% are devastating the DHT22.

I'm glad you mentioned that! I'll be making some of these for others as well, and since I plan on this being used mainly in grow rooms, grow tents, and greenhouses, maybe DHT22 isn't the best choice. With plants constantly transpiring, Humidity can get pretty high in a grow tent, especially if the one using it doesn't have much experience and skimps on the exhaust or something like that.

Back to the drawing board!