Node Mcu
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WiFI Bamboo Bathroom Scale

Records weight online via MQTT. Also displays time, date, inside temp, outside temp data received from a second existing controller.

IntermediateShowcase (no instructions)8 hours88

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Schematics

Scale Schematic

Scale Schematic including how ESP-NOW sends data from another existing NodeMCU.

Code

Programming notes

Arduino
For programming I just added the HX711_basic_example applicable code to my typical NodeMCU program.

ESP-NOW sends data directly between microcontrollers. No router needed.

ESP-NOW

I created an equation to correct for the zero offset and scale to read in pounds. It reads -548358 unloaded. NodeMCU is 32 bit so big numbers are no problem.

weightlbsraw = scale.read_average(20); // average 20 readings

weightlbs = (548358 + weightlbsraw)/9431.7; // equation in my case - unloaded zero offset is first raw number

It updates the unloaded zero offset (tare function) at 4 a.m. every day to counter any drift. That doesn't seem to be necessary so far but humidity changes over the year may affect the weight of the wood a bit.

It only displays and records weight if it is exactly the same, within 0.1 lbs, for 2 seconds.
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Node Mcu
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