
Vector gen
qu1j0t3/vector_gen
In first version of PCB there is a bug that leaves U6 Vss/Vdd pins floating and U5 Vdd floating:

I²C Weight Scale: strain gauges in a Wheatstone bridge amplified in an instrumentation amplifier, A/D converted and made available over I²C in a PIC microcontroller
I2c weight scale kicad is an open-source printed circuit board by simlun, from the simlun/i2c-weight-scale repository on GitHub. It is a 2-layer board of 43 × 49 mm with 13 parts on 19 nets, routed with 74 tracks and 5 vias.
It is built around the PIC12F1822-E/P, INA126U and LM336. Its parts include 5 resistors, 2 ICs, 2 connectors and 1 diode. It belongs with the audio and music and interfaces and adapters boards and the PIC boards of this library.
I²C Weight Scale: strain gauges in a Wheatstone bridge amplified in an instrumentation amplifier, A/D converted and made available over I²C in a PIC microcontroller.
I²C slave. Reading from the slave responds with a stable digital representation of the load on the strain gauges under a hacked ordinary weight scale.

The KiCad source files can be found under PCB/.
The schematic rendered as a PDF is reached by clicking the PNG below.. The
KiCad project depends on my component library
which should be checked out alongside this repository.
Simply buy a cheap kitchen weight scale, remove its PCB and instead take the 4x3=12 leads from the 4 strain gauges to create an external port from a 2.54 mm pin header.

The I²C Weight Scale PCB is a module that can connect to any weight scale of 4 strain gauges.


This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | VAL** | Mounting_Holes:MountingHole_2-7mm | MountingHole_2-7mm, MountingHole_2-7mm, MountingHole_2-7mm |
| 2 | 1K | Resistors_ThroughHole:Resistor_Vertical_RM5mm | R2, R4 |
| 1 | 10K | Resistors_ThroughHole:Resistor_Vertical_RM5mm | R5 |
| 1 | 1K5 | Resistors_ThroughHole:Resistor_Vertical_RM5mm | R1 |
| 1 | 4_STRAIN_GAUGES | Pin_Headers:Pin_Header_Straight_1x12 | P1 |
| 1 | 82 | Resistors_ThroughHole:Resistor_Vertical_RM5mm | R3 |
| 1 | I2C_RJ14 | simlun:RJ14_6P4C_right_angle_Molex_95009-7641 | J1 |
| 1 | INA126 | Sockets_DIP:DIP-8__300 | U1 |
| 1 | LM336 | Housings_TO-92:TO-92-Free-molded-wide-oval | D1 |
| 1 | PIC12F1822 | Sockets_DIP:DIP-8__300 | U2 |
It measures 43 × 49 mm and has 2 copper layers, 1.6 mm thick.
13 parts, built around the PIC12F1822-E/P, INA126U and LM336. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the simlun/i2c-weight-scale repository on GitHub, at the commit this page was made from: the board is PCB/i2c-weight-scale-kicad/i2c-weight-scale-kicad.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask simlun before reusing the design.

qu1j0t3/vector_gen
In first version of PCB there is a bug that leaves U6 Vss/Vdd pins floating and U5 Vdd floating:



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