📝 bill of materials
💬 cost per unit
The estimated cost for the components (without attrition) is around $100 (USD) without shipping and taxes, as of October 2022.
This value takes into account all the breaking points for a single E-TKT device and includes the manufacturing of 5 PCBs (4 layers) plus a stencil for the front layer.
A. structure & mechanic
| TYPE | SPEC | REF | QTY |
|---|---|---|---|
| 3D print | filament — PETG | link | ~220g |
| socket head screw | ISO 4762 - M3 x 40 - A2-70 | link | 1 |
| socket head screw | ISO 4762 - M3 x 20 - A2-70 | link | 18 |
| socket head screw | ISO 4762 - M3 x 16 - A2-70 | link | 7 |
| socket head screw | ISO 4762 - M3 x 10 - A2-70 | link | 4 |
| socket head screw | ISO 4762 - M3 x 8 - A2-70 | link | 2 |
| socket head screw | ISO 4762 - M3 x 6 - A2-70 | link | 9 |
| socket head screw | ISO 4762 - M4 x 10 - A2-70 | link | 1 |
| hex nut | DIN EN ISO 4032 - M3 - A2-70 | link | 10 |
| washer | DIN EN ISO 7090 - 3 - 200 HV - A2 | link | 9 |
| washer | DIN EN ISO 7090 - 6 - 200 HV - A2 | link | 1 |
| silicone pad feet | ⌀8x2mm | link | 4 |
| daisy wheel | MOTEX — uppercase, 43 chars. | link | 1 |
| deep groove ball bearing | 608-2Z | link | 1 |
| deep groove ball bearing | 623-2Z | link | 2 |
| extruder gear | MK8 40 teeth / 5mm axis | link | 1 |
B. sensors & actuators
| TYPE | SPEC | REF | QTY |
|---|---|---|---|
| hall sensor (breakout) | Keyes KY 003 | link | 1 |
| stepper driver (breakout) | A4988 | link | 1 |
| stepper motor | NEMA 17HS4023 + cable | link | 1 |
| stepper motor | 28BYJ-48 12V | link | 1 |
| servo | Towerpro MG-996R | link | 1 |
| neodymium magnet | ⌀2mm x 3mm length | link | 1 |
| LED | Clear white — DIP 2x5x7mm | link | 1 |
| OLED display | SSD1306, 128x64, monochrome white — 4 pin I²C | link | 1 |
C. PCB & components
| TYPE | SPEC — PACKAGE | REF | QTY |
|---|---|---|---|
| PCB | 4 layers, FR4, black solder mask — 99.57 mm x 76.2 mm | 1 | |
| stencil | top layer only (F.Cu) — 200mm x 150mm | 1 | |
| MCU | ESP32 — WROOM-32D (SMD) | ESP32-WROOM-32D-N4 | 1 |
| serial | USB Interface, Full Serial UART — SSOP-20 3.9x8.7mm (SMD) | FT231XS-R | 1 |
| driver | Darlington 50v 500mA — SOIC-16 3.9x9.9mm (SMD) | ULN2003ADRE4 | 1 |
| regulator | Switching, 4.5-28V 3A Output — SOT-23-6 (SMD) | TPS54302 | 1 |
| regulator | LDO 3.3V 800mA — SOT-223 (SMD) | AZ1117CH-3.3TRG1 | 1 |
| TVS diode | USB6B1 — SOIC-8 3.9x4.9mm (SMD) | USB6B1RL | 1 |
| inductor | 10uH 20% 7A — SRP6060 (SMD) | SRP6060FA-100M | 1 |
| buzzer | Electromagnetic 3V — CSS-0575A (SMD) | CSS-0575A-SMT | 1 |
| MOSFET | N-CH 0.22A, 50V, 1.5V — SOT-23 (SMD) | BSS138LT3G | 2 |
| BJT | 625mW, 25V, 1.5A — SOT-23 (SMD) | MMSS8050-L-TP | 2 |
| button | OFF-(ON) — 6X6X3.1mm (SMD) | B3FS-1000 | 3 |
| ferrite | 40 Ohms 5A — 0805 (SMD) | MH2029-400Y | 1 |
| fuse | 6V 750mA — 0805 (SMD) | 0ZCK0075FF2E | 1 |
| LED | LED white — 0603 (SMD) | SMLD12WBN1W1 | 12 |
| capacitor | Electrolytical 100uF 25V — 6.3x7.7 (SMD) | EMVE250ADA101MF80G | 1 |
| capacitor | Ceramic 22uF 25V X7R — 1210 (SMD) | C3225X7R1E226M250AB | 8 |
| capacitor | Ceramic 10uF 12V X7R — 0603 (SMD) | GRM188Z71A106KA73D | 6 |
| capacitor | Ceramic 0.1uF 50V X7R — 0603 (SMD) | C1608X7R1H104K080AA | 6 |
| capacitor | Ceramic 47pF 5V X7R — 0603 (SMD) | CGA3E2C0G1H470J080AA | 3 |
| resistor | Thick Film 100K — 0603 (SMD) | ERJ-3EKF1003V | 1 |
| resistor | Thick Film 11K — 0603 (SMD) | ERJ-3EKF1102V | 1 |
| resistor | Thick Film 10K — 0603 (SMD) | ERJ-3EKF1002V | 9 |
| resistor | Thick Film 5K1 — 0603 (SMD) | ERJ-3EKF5101V | 7 |
| resistor | Thick Film 2K — 0603 (SMD) | ERJ-3EKF2001V | 1 |
| resistor | Thick Film 100R — 0603 (SMD) | ERJ-3EKF1000V | 6 |
| resistor | Thick Film 27R — 0603 (SMD) | ERJ-3EKF27R0V | 4 |
| connector | USB-C 2.0 — GCT USB4105-GF-A | GCT USB4105-GF-A | 1 |
| connector | Barrel Jack 2mm/6.3mm, 5A 20V — DCJ200 | DCJ200-10-A-K1-K | 1 |
| connector | Conn_01x02_Male — Header 1x02 P2.54mm Vertical | M20-9990245 | 2 |
| connector | Conn_01x03_Male — Header 1x03 P2.54mm Vertical | M20-9990346 | 2 |
| connector | Conn_01x04_Male — Header 1x04 P2.54mm Vertical | M20-9770446 | 1 |
| connector | Conn_01x05_Male — Header 1x05 P2.54mm Vertical | M20-9990546 | 1 |
| connector | Conn_01x04_Male — Header 1x04 P2.54mm Horizontal | M20-9750446 | 1 |
| connector | Conn_02x08_Female — Socket 2x08 P2.54mm Vertical (A4988) | M20-7820842 | 2 |
* Alternative 6V power
| TYPE | SPEC — PACKAGE | REF | QTY |
|---|---|---|---|
| capacitor | Ceramic 0.33uF 50V X7R — 0603 (SMD) | CGA3E3X7R1H334M080AB | 1 |
| capacitor | Ceramic 0.1uF 50V X7R — 0603 (SMD) | C1608X7R1H104K080AA | 1 |
| regulator | Linear 6v 1.5A — TO-220 | L7806CV | 1 |
D. harnesses
| TYPE | SPEC | REF | QTY |
|---|---|---|---|
| cable | USB A to C data cable (firmware flash only) | 1 | |
| wiring | flat, flexible | link | 1 |
| connector | female - 1x02 P2.54mm dupont | link | 2 |
| connector | female - 1x04 P2.54mm dupont | link | 2 |
E. other
| TYPE | SPEC | REF | QTY |
|---|---|---|---|
| power | 12V 3A (real) 5,5mm x 2,1mm barrel jack, center positive | link | 1 |
| label tape | 9mm DYMO-compatible | link | 🦝 |