Which product(s) for building a simple wifi-accessible thermometer?

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pgf
 
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Which product(s) for building a simple wifi-accessible thermometer?

Post by pgf »

I'm an experienced professional firmware engineer. And retired. I've written lots of embedded code for microcontrollers in the past. I've written bare-board C for for Atmel and PIC chips, and dabbled with Arduino boards. So it's not the programming I need help with.

My problem is that there are SO MANY CHOICES these days that I think I could spend days just choosing a platform (TinyPICO? Feather? TinyS3?). The last time I chose a platform for home embedded projects I used the Atmel AVR series of chips. But that was before on-board WIFI, stackable peripherals, etc.

So: my immediate project need is to build a very simple temperature probe (i.e., digital thermometer) that I can query via wifi. I'd rather not have to implement fqttt or Home Assistant or any other big infrastructure. I'd prefer to just poll periodically with wget or curl.

Physically, I'm picturing a USB power supply, a board running some code in a small enclosure, and a temperature sensor. I could imagine maybe wanting a display of some sort, someday, perhaps on a separate project, so if the platform allowed for that, it would be a plus.

What should I get? Something standard, something that will be supported for a long time, something that lends itself to other similar simple projects, would be ideal. Linux support for the dev environment is essential -- it's all I use. My first reaction is to get a Feather board with an ESP8266 on it and hope it can do what I need. But as I say, I could spend days deciding it's the right choice.

Many thanks in advance, for helping me see the tree I need in this forest.

(And if there's an off-the-shelf solution to my immediate need, I'm happy to hear about that too, of course!)

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adafruit_support_mike
 
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Re: Which product(s) for building a simple wifi-accessible thermometer?

Post by adafruit_support_mike »

With Linux support as a requirement, you'll need a full computer like the Raspberry Pi. The Zero-W inexpensive and has Wifi:

https://www.adafruit.com/product/3400

The problem is that RasPi production has been hit by the global chip shortage and supply chain mess, and supply is expected to be constrained into 2023.

If you can live without an OS, the ESP32 is a Wifi microcontroller designed for power and low cost:

https://www.adafruit.com/?q=ESP32&sort=BestMatch

We have existing code that supports MQTT, which has become fairly standard for networked devices like sensors. It's a simple, text-based protocol that uses 'brokers' as message servers, and allows devices to push updates to the broker.

Our Adafruit.io platform provides a web-based interface to collect and display information:

https://learn.adafruit.com/welcome-to-adafruit-io

It's also integrated with services like IFTTT and Zapier so your data can trigger real-world actions like controlling devices and sending text messages.

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wwhite74
 
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Re: Which product(s) for building a simple wifi-accessible thermometer?

Post by wwhite74 »

ESP 32 will do it, you can code a basic webpage in the Arduino code. you can code the response however you want, could be json, or just a simple web page with the temp as the only text. You could then just call that page on any thing that can do simple http requests. It wouldn't have linux on the board itself, but if you've got some coding experience, you should be able to muck something together from the samples

Look at the STEMMA products, it's a simple i2c bus. just get the esp32 , and the stemma temp sensor, and a stemma cable, plug it together, and the demo code will have you reading the temperature in < 5 minutes. Then you'll just need to figure out how to get the ESP to handle web requests, also plenty of explainers on the web.

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pgf
 
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Re: Which product(s) for building a simple wifi-accessible thermometer?

Post by pgf »

Thank you both -- I'll focus on the ESP32, and I'll look at various methods of talking to the device. As I understand it, if a device supports MQTT, then a broker is required -- you can't talk to it directly. Is that the case? I'd prefer to not require the broker piece.

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adafruit_support_mike
 
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Re: Which product(s) for building a simple wifi-accessible thermometer?

Post by adafruit_support_mike »

You can also program the ESP32 to run a simple webserver, which you can query automatically with wget or curl.

(Sorry, I processed those statements differently when I read your original post the first time)

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RGRAVLIN
 
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Re: Which product(s) for building a simple wifi-accessible thermometer?

Post by RGRAVLIN »

I'm literally trying to build the same thing. After all the research so far I've come up with two solutions:

1. Feather w/ BME280
This option includes an all-in-one solution which is more expensive $25.00 USD just for the controller. No power.

2. DHT20 / AM2320 / AM2315C
This option seems less expensive per temperature module, but I personally don't know how replicate the rest of the Feather. I need wireless ESP32, and they'll all use USB-C power.

My choice so far (literally in my cart) is going to be the Feather w/ BME280 simply because it's easier. I'm willing to shell out the extra $$$ per sensor if I can far more easily create the supporting code to hydrate the data store with the sensor information.

My goal at this time is to simply use a simple HTTP protocol to send the points to a metrics TSDB backend. In this way I should be able to control my own data with open source software, and export it to any other analysis tool I would want.

I would love to discuss more about this, but I'm going to try the Feather!

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