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ThomDietrich / SenseoWifi

Wifi'ify the Senseo coffee maker. Circuit and firmware for an internal Senseo hack to monitor and control the daily coffee brew (via MQTT) ☕️📶
GNU General Public License v3.0
90 stars 23 forks source link

(Improvement) Replace Step Down AC-DC Converter (220V to 5V) by Hi-Link-ac-dc #12

Closed diogopms closed 5 years ago

diogopms commented 6 years ago

Note: This is not a real issue, but an improvement to the PCB.

What do you think, about changing to: https://pt.aliexpress.com/item/Hi-Link-ac-dc-power-module-5v-3w-220v-isolated-ac-dc-converter/32360232521.html

VinceMasuka commented 6 years ago

Works flawlessly. I took the same on my setup. http://www.hlktech.net/product_detail.php?ProId=54

In the 7820 it fits perfectly inside this trapezium shaped spot: 2018-09-13_15h39_47 (placed on it's own dedicated PCB)

ThomDietrich commented 5 years ago

Looks good indeed. Why would you recommend this one over the one I've linked?

VinceMasuka commented 5 years ago

Perhaps because it comes in a enclosure? grafik (inside it's pretty much the same, I guess)

Actually that might be preferable of sorts, as there is water around and you might would like the idea of some extra "shielding"... Besides that it's like a question of personal taste. I just took this one, as your suggested one was not available at my be trusted retailer.

ThomDietrich commented 5 years ago

Fine by me. Please create a PR against the README.md as an alternative product in the components table.

Ditoxius commented 5 years ago

Hi, i have another question regarding the supply voltage.

The senseo µC is powered the whole time with 5V via a capacitive divider and zener diode. Have you tried using its supply voltage to power the WeMos module instead of installing a separat step-down converter?

Thank you for your project....i hope to make my coffee maker smart, soon :D

ThomDietrich commented 5 years ago

Yes. I tried and I did a few thought experiments on the topic with colleagues. The problem is (please correct me if you disagree) that such a circuit has a narrow operating point and experiments showed that voltage drops as soon as more than a few milliamps are consumed.

Another problem is the missing divide of electrical potentials between the Senseo supply and the USB connection (think optocouplers).

I very much prefer the decoupled solution for its simplicity and the flexibility in build in troubleshooting. Lastly and maybe most importantly: The solution comes as safe as it can get (I hope :) ).

I'll close the issue because the "improvement" found its way in the README. Feel free to continue with the discussion!