raspmod
Posts: 31
Joined: Sun Nov 25, 2018 3:48 am

Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 5:50 am

Hi All - I am looking to achieve a small fun side project:

I'd I really like to be able to put together something that I can stick in my fridge w/o a breadboard, but will sit in a case, be battery powered, and have an LCD, just to take temperatures - an academic / learning project inspired by my friend's broken fridge.

I feel like going for a kit w/all the parts is a good idea. These seem like a good way to start:

Pico Pi - https://www.amazon.com/UCTRONICS-Raspbe ... op?ie=UTF8

but it seems like the lcd is not the same as the Getting Started manual -https://www.uctronics.com/download/Data ... %20v10.pdf

or possibly

Esp 32 - https://www.amazon.com/ESP32-WROVER-Con ... r_1_1_sspa

If possible looking to keep costs less than $100. I am versed in Linux and Python. I have 2 rpi 4's - (I could use one of those if I wanted to take one offline). I have used the esp8266 and flashed up a storm w/fun wifi hacks.

However, I am an electronic NOOB! (but am learning slowly) and frankly can't solder in my apt / don't really want to.

I apologize for wandering here but then I wonder - am I mistaken about the Pico? It *seems* like I can get that on AMZN for single single dollars, plug it into my PC and use it's internal temp sensor and I could at least view the data on my pc via serial port w/o a bread board.

Admittedly w/o a case and all the other stuff. But I could at least start and then build up from there. (I recently sold my Arduino b/c I don't know C but (I guess it can work w/python) I am just afraid I will get lost using a bread board w/o someone literally walking me step by step and just get frustrated (I am working on my patience!).

I realize I am coming off a bit NOOBish, but I have stop/started learning electronics a few times and am trying to build up some momentum and some personal "wins".

Any help is appreciated!

ame
Posts: 5209
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 6:09 am

Batteries don't like being cold. I suggest you put the temperature sensor in the fridge, with a thin wire coming to the outside, probably past the rubber door seal. Then you can put the microcontroller and batteries outside. Better still, plug a tiny USB power supply in and use that.

For the micro, an ESP8266 in Wemos D1 Mini Pro form factor is ideal. It can run ESPeasy or something to send your data somewhere.
Hmm. What can I put here?

User avatar
bensimmo
Posts: 5626
Joined: Sun Dec 28, 2014 3:02 pm
Location: East Yorkshire

Re: Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 6:41 am

Fridges are only at about 4degC and 🔋 will be fine.

Freezer may be a bit different. Check the batter spec and the capacity (it drops the lower you go).

Can tag a 3V cell directly to some of the ESP boards, you might need a super capacitor too.
Or a Lipo 3.7V cell is better.
If you have the money buy the pico and the ESP.
Then have a play with both.


Note, as above though it is probably better and easier to just run very thin wire into the fridge. Especially when getting it going, worry about power afterwards.
Grab a DS18B20 temp sensor or five and you're off.
Grab a light sensor and you can check when it has been opened... Or if the light really does turn off ;-)

You could even go humidity and pressure and sound and......😂

User avatar
bensimmo
Posts: 5626
Joined: Sun Dec 28, 2014 3:02 pm
Location: East Yorkshire

Re: Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 6:47 am

Do look at the cost and setup of premade ones on Amazon, a 2x wireless sensor and external lcd display is about £17.

But no fun there.
Unless you rip it apart to see how it is made or you try use their sensors and grab the data.

lurk101
Posts: 1561
Joined: Mon Jan 27, 2020 2:35 pm
Location: Cumming, GA (US)

Re: Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 2:11 pm

The small displays shown at the kit links above are not LCD displays. They're LED displays which draw considerably more power and are less suitable for long term battery powered applications. For environment sensing I'd pick a BME280 for its precision. A single cell Lion or LiFe battery could power a Pico at fridge temperatures.

ESP was mentioned, as in ESP32 or ESP8285. It would be a better choice for this application since its power demands are much lower, has builtin deep sleep and wake up, and supports I2C or SPI to control the display and sensor.

A light sensor could be added such that the display only turns on when the fridge door is opened.

I'm not sure what are the implications are of keeping battery chemistry in the same box as your food stuff though?
It took 60 years of very difficult engineering to go from the invention of transistors to the smartphone with no new physics involved in the process.

raspmod
Posts: 31
Joined: Sun Nov 25, 2018 3:48 am

Re: Suggestions for Starting out w/a Temperature Probe

Sun Jun 19, 2022 3:58 pm

Thanks for all the thoughts here. I kept researching and You-tubing.

Based on my personal knowledge I went with a Pi Pico (**with** headers) and a Waveshare 1.8inch LCD Display that will slot right in to the Pico.

I have a little portable usb battery that should power the pico.

I will place the bundle on a piece of plastic (on top of a satin pillow (j/k) ) in the fridge.

Crazy all these youtubers no longer have affiliate links - This is the time I will just buy whatever the experts say - as long as it works and it's easy - remember - I am a NOOB - I cannot spend time troubleshooting voltages or anything more than boiling water :)

So, worst case some $$ and time are at risk, no biggie -- I just clicked buy at AMZN. (I am willing to risk it all in the name of science)

I will update this thread with my findings once I make progress!

raspmod
Posts: 31
Joined: Sun Nov 25, 2018 3:48 am

Re: Suggestions for Starting out w/a Temperature Probe

Tue Jun 21, 2022 9:30 pm

Got the LCD but it's pretty much a non starter. Beautiful Screen and works but seems very very difficult to use.

viewtopic.php?t=301668&sid=cc6149016628 ... b951ee4b2a

https://www.instructables.com/WaveShare ... y-Workout/

I spent an hour+, apart from copy/pasting some code to exercise the lcd, I've gotten nowhere so far...

raspmod
Posts: 31
Joined: Sun Nov 25, 2018 3:48 am

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 12:33 pm

Yeap. Sent all the gear back. Spent a few hours w/all this - I generally don't give up but this is a lost cause. I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins. Can't figure out the LCD. My breadboard can't even support the pico and it can't interface w/the esp8266 following youtubers. It's taken too long. I clearly need a kit that I know all the parts work and are supported. Maybe 'll try a bespoke project sometime in the future.

User avatar
rpdom
Posts: 20215
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 2:42 pm

raspmod wrote:
Thu Jun 23, 2022 12:33 pm
I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins.
Only 3 of the pins on the DHT sensor is used. The other doesn't do anything.
Unreadable squiggle

memjr
Posts: 1187
Joined: Fri Aug 21, 2020 5:59 pm

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 2:48 pm

rpdom wrote:
Thu Jun 23, 2022 2:42 pm
raspmod wrote:
Thu Jun 23, 2022 12:33 pm
I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins.
Only 3 of the pins on the DHT sensor is used. The other doesn't do anything.
Sure, you knew that! If only someone would come up with a way to find that kind of information without the need to leave the house or write letters to the manufactures asking them to send us printouts of specs and datasheets...

lurk101
Posts: 1561
Joined: Mon Jan 27, 2020 2:35 pm
Location: Cumming, GA (US)

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 5:30 pm

memjr wrote:
Thu Jun 23, 2022 2:48 pm
rpdom wrote:
Thu Jun 23, 2022 2:42 pm
raspmod wrote:
Thu Jun 23, 2022 12:33 pm
I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins.
Only 3 of the pins on the DHT sensor is used. The other doesn't do anything.
Sure, you knew that! If only someone would come up with a way to find that kind of information without the need to leave the house or write letters to the manufactures asking them to send us printouts of specs and datasheets...
The 1st hit on DuckDuckGo links to an article that makes it pretty obvious!
Search terms like "dht spec" lead to much the same including chip specs.
So, what's the problem?
It took 60 years of very difficult engineering to go from the invention of transistors to the smartphone with no new physics involved in the process.

memjr
Posts: 1187
Joined: Fri Aug 21, 2020 5:59 pm

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 5:51 pm

lurk101 wrote:
Thu Jun 23, 2022 5:30 pm
memjr wrote:
Thu Jun 23, 2022 2:48 pm
rpdom wrote:
Thu Jun 23, 2022 2:42 pm

Only 3 of the pins on the DHT sensor is used. The other doesn't do anything.
Sure, you knew that! If only someone would come up with a way to find that kind of information without the need to leave the house or write letters to the manufactures asking them to send us printouts of specs and datasheets...
The 1st hit on DuckDuckGo links to an article that makes it pretty obvious!
Search terms like "dht spec" lead to much the same including chip specs.
So, what's the problem?
Did you read just the first 4 words of my post or did you intentionally decide to ignore the sarcasm clearly contained after those?

ame
Posts: 5209
Joined: Sat Aug 18, 2012 1:21 am
Location: New Zealand

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 9:33 pm

raspmod wrote:
Thu Jun 23, 2022 12:33 pm
Yeap. Sent all the gear back. Spent a few hours w/all this - I generally don't give up but this is a lost cause. I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins. Can't figure out the LCD. My breadboard can't even support the pico and it can't interface w/the esp8266 following youtubers. It's taken too long. I clearly need a kit that I know all the parts work and are supported. Maybe 'll try a bespoke project sometime in the future.
Try this kit:

https://www.amazon.com/Play22-Kids-Gard ... B08QQF989N
Hmm. What can I put here?

memjr
Posts: 1187
Joined: Fri Aug 21, 2020 5:59 pm

Re: Suggestions for Starting out w/a Temperature Probe

Thu Jun 23, 2022 10:46 pm

raspmod wrote:
Thu Jun 23, 2022 12:33 pm
Yeap. Sent all the gear back. Spent a few hours w/all this - I generally don't give up but this is a lost cause. I could get temperature from the pico but the DHT temp probe came w/3 pins. Youtubers have 4 pins. Can't figure out the LCD. My breadboard can't even support the pico and it can't interface w/the esp8266 following youtubers. It's taken too long. I clearly need a kit that I know all the parts work and are supported. Maybe 'll try a bespoke project sometime in the future.
All those parts probably did work. You just did not know how to do it. Apparently you need to sharpen your google searching skills as there are tons of websites out there with sample code in how to make those things work, either by themselves or together, in one way or another.

Return to “General discussion”