4 layers90.2 × 40 mm
Radar v2
ckflight/FMCW-RADAR
Frequency Modulated Continuous Wave Radar hardware and software design files with 26 dBm output power covering around 250 m.
270 parts59GPL-3.0
4 layers71.1 × 94 mm
Ipotcas
SuperTails/ipotcas12IP over Tin Can and String - Connecting to the internet over two tin cans and a piece of string
- Size
- 71.1 × 94 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 75
- Nets
- 184
- Pads
- 394
- Tracks, vias
- 394, 45
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 15 May 2025
- Updated
- 30 Aug 2025
Overview
Ipotcas is an open-source printed circuit board by SuperTails, from the SuperTails/ipotcas repository on GitHub. It is a 4-layer board of 71.1 × 94 mm with 75 parts on 184 nets, routed with 394 tracks and 45 vias.
It is built around the MCP602-I/P and SG-210STF. Its parts include 24 capacitors, 23 resistors, 14 connectors, 5 ICs and 5 diodes.
Main components
2
MCP602-I/P
PDIP-8-40℃~+85℃ 1pA 1pA 2 2.3V/us 2.5uV/℃ 2.7V~6V 2.8MHz 22mA 230uA 29nV/√Hz@1kHz 700uV 90dB Built-in compensation、ESD protection Rail-to-rail output PDIP-8 Operational Amplifier ROHSMicrochip TechnologyOperational Amplifier
SG-210STF
SMD2520-4P-40℃~+85℃ 1.6V~3.6V 1.8mA 13MHz ±50ppm SMD2520-4P Crystal Oscillators ROHSSeiko EpsonOscillators
README
README.md
IP over Tin Can and String (IPoTCaS, pronounced "eye-poh-tee-kass"), also known as EtherKnit or "what is this annoying buzzing noise", is a revolutionary new way to connect to the internet over a fiber connection.
Using only two pieces of string and lots of annoying sounds, IPoTCaS can create a 6.9 kbps connection capable of browsing the web, downloading files, and giving you a newfound distaste for web bloat.
Physical Setup
The linear rails are sourced from two listings on Amazon, but I'd highly recommend just using the first one because the wider rails are much worse (though the CAD will require some modification):
Any generic Kevlar kite string will probably work,
but I used specifically
this amazon listing
from emma kites.
The mount CAD is available on Onshape. I have not tested with materials other than PLA. The model is designed to work with metric heat-set inserts to hold down the rails.
Modulation
IPoTCaS uses 32-QAM and 12-carrier OFDM between 7 and 14 kHz.
Parts
75| Qty | Value | Footprint | References |
|---|---|---|---|
| 11 | 100nF | Capacitor_SMD:C_0402_1005Metric | C1, C2, C5, C8, C9, C10, C12, C13, C19, C22, C23 |
| 7 | 47µF | Capacitor_SMD:C_0805_2012Metric | C14, C15, C16, C17, C18, C20, C24 |
| 5 | 1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R21, R22, R23, R24, R25 |
| 5 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1, D2, D3, D4, D5 |
| 4 | 22 | Resistor_SMD:R_0402_1005Metric | R7, R8, R9, R11 |
| 4 | Conn_01x03 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J7, J8, J10, J13 |
| 3 | Screw_Terminal_01x02 | ScrewTerminal:TE_282837-2 | J1, J2, J3 |
| 2 | 100nF | Capacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolder | C6, C7 |
| 2 | 10µF | Capacitor_SMD:C_0402_1005Metric | C3, C4 |
| 2 | 1k | Resistor_SMD:R_0402_1005Metric | R15, R16 |
| 2 | 220k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R27, R30 |
| 2 | 4.7k | Resistor_SMD:R_0402_1005Metric | R2, R5 |
| 2 | 470k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R10, R12 |
| 2 | AudioJack4 | Connector_Audio:Jack_3.5mm_PJ320D_Horizontal | J6, J11 |
| 1 | 10 | Resistor_SMD:R_0402_1005Metric | R6 |
| 1 | 100µF | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C11 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R28 |
| 1 | 10k | Potentiometer_THT:Potentiometer_Bourns_3296W_Vertical | R3 |
| 1 | 1k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R1 |
| 1 | 2.2k | Resistor_SMD:R_0402_1005Metric | R29 |
| 1 | 22k | Resistor_SMD:R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R4 |
| 1 | 47µF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C21 |
| 1 | Barrel_Jack_Switch | Barrel:CUI_PJ-002B | J5 |
| 1 | Conn_01x02 | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J14 |
| 1 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J9 |
| 1 | Conn_01x06 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J4 |
| 1 | Conn_01x07 | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Vertical | J12 |
| 1 | Jumper_2_Open | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | JP1 |
| 1 | LM741 | Package_SO:SOP-8_3.9x4.9mm_P1.27mm | U3 |
| 1 | LOGO | Careers:salixwhat_1in | G*** |
| 1 | MCP602 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U2 |
| 1 | NUCLEO144-F767ZI | Module:ST_Morpho_Connector_144_STLink | U1 |
| 1 | SG-210STF | Oscillator:Oscillator_SMD_SeikoEpson_SG210-4Pin_2.5x2.0mm | Y1 |
| 1 | SolderJumper_2_Bridged | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP3 |
| 1 | TC7662Bx0A | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | ~ | Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.45x3.45mm_ThermalVias | U5 |
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Questions
How big is the Ipotcas PCB?
It measures 71.1 × 94 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Ipotcas use?
75 parts, built around the MCP602-I/P and SG-210STF. 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.
Where can I download the Ipotcas KiCad files?
From the SuperTails/ipotcas repository on GitHub, at the commit this page was made from: the board is pcb/ipotcas/ipotcas.kicad_pcb and its schematic pcb/ipotcas/ipotcas.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Ipotcas design in my own project?
Its repository states no licence, so its author keeps all rights: ask SuperTails before reusing the design.