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Desk balance

kurikennn·desk-balance·hardware/kicad/desk_balance.kicad_sch

Desk balance

About the Desk balance PCB

Desk balance is an open source ESP32 PCB design by kurikennn, published on GitHub under the MIT license. It is a board, with 20 components from 13 distinct parts.

Its main chip is the ESP32-DevKitC (WROOM-32), from the ESP32 family. Other key parts include the ADS1220 module (CJMCU-1220) and TMP117 Qwiic (bonded to LC1). By type, the board carries 7 capacitors, 4 resistors, 3 ICs, 2 connectors and 2 jumpers.

It belongs with the sensors and dev boards & breakouts designs in this gallery.

From the project

A two-component strain-gauge force balance on a desk: two 500 g load cells, an ADS1220 24-bit ADC and an ESP32. It is a small analogue of a wind-tunnel balance, and is used to measure the four things that limit one:

A two-component strain-gauge force balance on a desk: two 500 g load cells, an ADS1220 24-bit ADC and an ESP32. It is a small analogue of a wind-tunnel balance, and is used to measure the four things that limit one:

- excitation stability; - temperature drift; - calibration; - interaction between components.

The whole software chain is built and verified against a simulated balance first:

Main components on the Desk balance

ESP32-DevKitC (WROOM-32)ADS1220 module (CJMCU-1220)TMP117 Qwiic (bonded to LC1)

Desk balance bill of materials (BOM)

20 components, 13 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ESP32-DevKitC (WROOM-32)
U1
1
ADS1220 module (CJMCU-1220)
U2
1
TMP117 Qwiic (bonded to LC1)
U3
1
GX12-4 bridge 1
J1
1
GX12-4 bridge 2
J2
1
AVDD to J1 pin 1 (module wiring)
JP1
1
AVSS to J1 pin 2 (module wiring)
JP2
1
TAL221 500 g (vertical, ch0) via W1
LC1
1
TAL221 500 g (horizontal, ch1) via W2
LC2
2
C_diff TBD (100n)
C1, C4
4
C_cm TBD (10n)
C2, C3, C5, C6
1
C_ref TBD (100n)
C7
4
R_in TBD (1k)
R1, R2, R3, R4

Desk balance design files

The KiCad project lives in the kurikennn/desk-balance repository on GitHub; these links point at the commit this page was built from.

Desk balance: common questions

What microcontroller does the Desk balance use?

The Desk balance is built around the ESP32-DevKitC (WROOM-32), from the ESP32 family.

How many components are on the Desk balance?

20 components, from 13 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Desk balance design files?

From the kurikennn/desk-balance repository on GitHub, which has the schematic and the BOM; the links under Design files point to each one.

Can I use the Desk balance design in my own project?

Yes, under the terms of its MIT license, which kurikennn chose for the repository.

Can I test firmware for the Desk balance without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.

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