Subj : Re: OIL level sensor (was ODD DNS behaviour on Pi ZERO W with Bullseye
To   : All
From : The Natural Philosopher
Date : Wed Nov 19 2025 12:16:42

Subject: Re: OIL level sensor (was ODD DNS behaviour on Pi ZERO W with Bullseye OS)

On 19/11/2025 11:11, Daniel James wrote:
> On 19/11/2025 10:08, The Natural Philosopher wrote:
>> Oh. I designed a board with
>>
>> - a Pi Pico W.
>> - a three pin temperature sensor ( TMP36) to monitor outside temperature
>> - an ultrasonic transmitter/receiver ( HCRS04) on it
>> - a nano power timer that (Was a sparkfun nano power switch˙ TPL5110 
>> until I blew it up and replaced it with a sub-board˙ with an Adafruit 
>> TPL5110 Low Power Timer ) wakes up every 2 hours, tries to make 
>> contact with the wifi, sends a short message to the server, and then 
>> commits suicide and shuts the timer down again.
> 
> OK, thanks. What sort of oil tank do you have and how do you fit the 
> sensor to it?

One of these basically

https://www.fueltankshop.co.uk/2500-litre-oil-tank-titan-h2500gr/p5305

The tank already had a hole in the top to take an oil watchman sensor, 
so I 3d printed a case to use the same mounting holes and gasket. I will 
need to open up the hole a bit for the ultrasonics
> 
> I'm part-way through designing something similar myself, but using an 
> ESP8266 to control the sensor and talking mqtt to a Pi (happens to be a 
> Pi3B, because I have one always-on for other things but I could have 
> used a ZeroW). It's really at Proof-of-Concept stage at present.
> 
Well since I am 100% custom I didn't bother with mqtt - I simply send a 
short text string . The more problematical bit is establishing a wifi 
connection and what to do if it fails to connect.

If I had Ethernet out there I would never have gone to the complexity of 
battery operation....

> I have a 3V-compatible HCSR04 to play with, but was wondering whether an 
> ir laser ToF device might be better. Those ultrasonic sensors are a bit 
> chunky ... (I'm told there is no chance of the laser in,say, a VL53L1X 
> igniting heating oil vapour!)
> 
Good with the 3v version Mine isn't and I expect it to get sketchy at 
around 3.9V.
If that proves to be a problem I'll probab;y make a new board up and 
transfer the modules from the existing...

> I haven't yet put either anywhere near the oil tank, yet. I'm using 
> readings from a BME280 to test the logic.
> 
> I have a "Cheap Yellow Display" (ESP32 with LCD) that acts as a mqtt 
> client and display panel ... it can record data (but doesn't yet) but 
> I'll probably want something more sophisticated later ... as I say, it's 
> all PoC at present.
> 
Well the history of my controller goes back 20 years when I installed 
everything and just threw in 'enough to get it working'

But I never had proper control. And the RF thermostat was bulky and not 
especially reliable. So I finally decided to mess around with a Pi.

Because the website I built on the zero has everything I want to know 
exactly where I want it, the experience is MUCH better.

Sometimes stuff gets stuck after a power cut. But hard resets have 
always fixed it.

I don't like the commercial solutions that rely on a cloud somewhere.


-- 
Truth welcomes investigation because truth knows investigation will lead 
to converts. It is deception that uses all the other techniques.


--- PyGate Linux v1.5
 * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

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