OM-FlexGrid-Rigid
About the OM-FlexGrid-Rigid PCB
OM-FlexGrid-Rigid is an open source ESP32 PCB design by Open-Muscle, published on GitHub under the CERN-OHL-S-2.0 license. It is a 4-layer board measuring 33 × 65.5 mm, with 58 components from 37 distinct parts.
Its main chip is the ESP32-S3-WROOM-1-N16R8, from the ESP32 family. Other key parts include the ICM-42688-P, CD74HC4067M, TPS7A03, LTC4054ES5-4.2 or STC4054GR and USBLC6-2SC6. By type, the board carries 18 resistors, 11 capacitors, 8 connectors, 6 ICs, 5 diodes and 3 transistors.
It belongs with the sensors and wearables designs in this gallery.
From the project
60-sensor wearable with flexible PCB and pressure matrix
Unboxing & Setup: assembling the FlexGrid V4 walks through hand-soldering the parts JLCPCB does not populate (ESP32-S3 module, CD74HC4067 mux, ZIF/FFC connector, USB-C, buttons, RGB LED), the USBLC6 180-degree rotation fix, and first power-on with the flex sensor mated. The microSD socket and haptic parts are deferred to a future video.
For people who want to review the design without opening KiCad:
Main components on the OM-FlexGrid-Rigid
OM-FlexGrid-Rigid bill of materials (BOM)
58 components, 37 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ICM-42688-P | LGA-14_3x2.5mm_P0.5mm_LayoutBorder3x4y | IC1 |
| 1 | CD74HC4067M | TSSOP-24_4.4x7.8mm_P0.65mm | U1 |
| 1 | ESP32-S3-WROOM-1-N16R8 | ESP32-S3-WROOM-1-N16R8 | U2 |
| 1 | TPS7A03 | SOT-23-5 | U3 |
| 1 | LTC4054ES5-4.2 or STC4054GR | TSOT-23-5 | U4 |
| 1 | USBLC6-2SC6 | SOT-23-6 | U5 |
| 2 | IRLML2060 | SOT-23 | Q1, Q3 |
| 1 | VP0610T or BSS84 | SOT-23 | Q2 |
| 1 | Conn_01x06_Pin | PinHeader_2x03_P1.27mm_Vertical | J1 |
| 1 | BAT Terminal | PinHeader_1x02_P2.54mm_Vertical | J2 |
| 1 | Conn_01x20 | 687120183722-20P-Bottom | J3 |
| 1 | USB_C_Receptacle | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J4 |
| 1 | Conn_01x02 | PinHeader_1x02_P2.00mm_Vertical | J5 |
| 1 | Conn_01x03_Pin | PinHeader_1x03_P2.54mm_Vertical | J6 |
| 1 | Conn_01x02_Pin | PinSocket_1x02_P2.00mm_Vertical | J7 |
| 1 | Micro_SD_Card | CONN_503398-1892_MOL | J9 |
| 5 | SW_Push | EVQP2P02M | BOOT1, MENU1, SELECT1, SW_PWR1, SW_RST1 |
| 1 | MAX16054 | TSOT-23-6 | MAX1 |
| 1 | Conn_01x04 | PinHeader_1x04_P2.54mm_Vertical | SCRN1 |
| 1 | 1N5819 | D_SOD-123 | D1 |
Show 17 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | CHRG LED | LED_0805_2012Metric | D2 |
| 1 | BAT54C | SOT-23 | D3 |
| 1 | 1N4007 | D_SOD-123 | D4 |
| 1 | LED_RGB | LED_RGB_PLCC-6 | D5 |
| 1 | 100 nF | C_0603_1608Metric | C5 |
| 2 | 4.7uF | C_0805_2012Metric | C6, C7 |
| 2 | 2.2 uF | C_0603_1608Metric | C8, C11 |
| 1 | 100 uF | C_0603_1608Metric | C9 |
| 1 | 0.1 uF | C_0603_1608Metric | C10 |
| 4 | 100 pF | C_0603_1608Metric | C12, C13, C14, C15 |
| 3 | 5.1K | R_0603_1608Metric | R1, R2, R6 |
| 1 | 1K | R_0603_1608Metric | R3 |
| 1 | 2k | R_0603_1608Metric | R4 |
| 1 | 150 | R_0603_1608Metric | R5 |
| 3 | 100k | R_0603_1608Metric | R7, R8, R9 |
| 6 | 10k | R_0603_1608Metric | R10, R11, R12, R13, R14, R15 |
| 3 | 330 | R_0603_1608Metric | R16, R17, R18 |
OM-FlexGrid-Rigid design files
The KiCad project lives in the Open-Muscle/OpenMuscle-FlexGrid repository on GitHub; these links point at the commit this page was built from.
OM-FlexGrid-Rigid: common questions
What microcontroller does the OM-FlexGrid-Rigid use?
The OM-FlexGrid-Rigid is built around the ESP32-S3-WROOM-1-N16R8, from the ESP32 family.
How big is the OM-FlexGrid-Rigid PCB?
The OM-FlexGrid-Rigid measures 33 × 65.5 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the OM-FlexGrid-Rigid?
58 components, from 37 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 OM-FlexGrid-Rigid design files?
From the Open-Muscle/OpenMuscle-FlexGrid repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the OM-FlexGrid-Rigid design in my own project?
Yes, under the terms of its CERN-OHL-S-2.0 license, which Open-Muscle chose for the repository.
Can I test firmware for the OM-FlexGrid-Rigid 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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