Lucian SABO
Published © CC BY-NC-SA

Healthzuilla Scale

Wireless food scale with HTTP API.

IntermediateFull instructions provided3 days103
Healthzuilla Scale

Things used in this project

Hardware components

Wemos D1 Mini
Everything ESP Wemos D1 Mini
×1
HX711 Load Cell Amplifier Module
×1
Li-Ion Battery 1000mAh
Li-Ion Battery 1000mAh
I used a Samsung battery from an old phone.
×1
Lithium battery charger module 1A TP4056
×1
Prototyping board (Perfboard)
×1
SparkFun Nokia 5110 LCD
I actually used a cheap Chinese board with the same pinout.
×1
SparkFun Load Cell 5kg Strait Bar
I simply used a cheap scale, removed the electronics and used the case with load cell, and the two push buttons. This way you have a stable base, suitable for weighting.
×1
Logic Level FET N-Channel
Logic Level FET N-Channel
Q1 in the schematics
×1
NDB6020P P-Channel Logic Level Enhancement Mode Field Effect Transistor
Q2 in the schematics. You can use any P Channel Logic Level Mosfet able to handle at least 500mA at -3.3V,. This one is rated for up to 24 Amps, so it's a bit bulky, but didn't had a smaller one.
×1
Capacitor 100 nF
Capacitor 100 nF
×3
2N3904 - common NPN bipolar junction transistor
Q3 in the schematics.
×1
Capacitor 10 nF
Capacitor 10 nF
×1
Capacitor 47 µF
Capacitor 47 µF
×1
LDR (Light Dependent Resistor)
×1
Resistor 10k ohm
Resistor 10k ohm
×4
Resistor 1k ohm
Resistor 1k ohm
×1
Resistor 221k ohm
Resistor 221k ohm
×1
Resistor 22.1 ohm
Resistor 22.1 ohm
×1
Jumper wires (generic)
Jumper wires (generic)
×1
Pushbutton switch 12mm
SparkFun Pushbutton switch 12mm
I used the push buttons which came with the cheap scale I disassembled
×2
LED (generic)
LED (generic)
This is used to light up the logo. I used a white bright LED from an old solar lamp.
×1
Resistor 1k ohm
Resistor 1k ohm
Series Resistor for the logo. Maybe you should use a higher one to be safe like 22 ohm
×1

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)
Jigsaw
Hot glue gun (generic)
Hot glue gun (generic)
Started with hot glue, but found it was not adhering properly to smooth surfaces so I I actually used silicone. You can use any glue to bond plastic and wood (if your enclosure is made out of wood)
Hand Drilling Machine

Story

Read more

Schematics

Simplified circuit

This is a simplified schematic. Missing:
- soft latching circuit
- main switch
- auto backlight LDR circuit
Simplified circuit bb s1ogndqr1o

Simplified circuit

Simplified circuit in Fritzing

Latching circuit Schematic

Latching circuit schem 9p8usjqv2u

Connection board

This is the connection board. Red marks battery/USB voltage (3.7 - 5V), Orange marks stabilized 3.3V.

Latching circuit Schematic in Fritzing

Only the latching part

Auto LCD Backlight circuit schematic

Auto backlight circuit schem o80bsl3li7

Auto LCD Backlight circuit schematic (Fritzing)

Code

Healthzuilla Scale Github repository

Clone the repository or download the source code

Credits

Lucian SABO

Lucian SABO

1 project • 0 followers

Comments