A year or so ago I made this beautiful device. It lives under my kitchen counter. The wire with the green heat-shrink leads to a button. Pressing the button starts the water. The water comes in from the white tube on the right, the round thing is a little flowmeter waterwheel that measures the water, and the solenoid controls the flow.

The code is here: https://pastebin.com/1xPHa6NM

The problem is that once in a while, about one time in 100, the water doesn't stop.

It is supposed to stop after the "requested_amount" is reached. In case it doesn't, it's also supposed to stop if the button is pressed again. This works most of the time, but not always. Sometimes it just keeps going and I have to use a little manual valve to physically stop the water flow. No good.

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https://preview.redd.it/exl2ij6ek4fb1.jpg?width=2283&format=pjpg&auto=webp&s=dc3eff3f2ec800a520f82b16db18088e7950842d

I can't figure out how to save the logs so that I can read them later. But I have just figured out how to capture the "status" updates that get sent via MQTT. It looks like this when the water starts and stops correctly:

https://preview.redd.it/yzaspt8765fb1.png?width=972&format=png&auto=webp&s=b0f3d433caf799fd28e1cbec7eb62db54f859d4a

So... troubleshooting. How do I go about figuring out what the problem is?

1. How can I read the logs after the fact? Would that help?
2. How can I send more useful information via mqtt?
3. Are there any flaws in my code that would somehow cause this?
4. What else would you recommend?

Are my expectations too high? I mean, there must be millions of beverage dispensers out there that start at the push of a button, measure out a pre-determined amount of liquid and then shut off reliably.

Flowmeter: https://www.amazon.com/gp/product/B08ZD85CSK

Solenoid Valve: https://www.amazon.com/gp/product/B016MP1HX0

I'd appreciate any advice. I've come so far with this project, but this is a pretty fatal flaw. Thank you!

If you're curious, it takes 3200 pulses to fill my coffee machine. The reason I have it as a variable coming from home assistant instead of hard-coded is that I want to build a v2 of the device where I can request any amount of water. (I can calculate for example that a cup of water would be 448 pulses of water).