{
 "slug": "kiisu-v4",
 "name": "KIISU V4B",
 "maker": "Rainwalker OÜ",
 "category": "multitools",
 "categoryLabel": "Multitools",
 "status": "preorder",
 "statusLabel": "Preorder",
 "description": "A credit-card-sized development board with sub-GHz, NFC, RFID, infrared and Bluetooth that runs most Flipper Zero firmware.",
 "goodFor": "Carry a wallet-sized Flipper-firmware board for sub-GHz, NFC, RFID and infrared experiments.",
 "youNeed": "A microSD card, an LIR2032 cell (not CR2032) or USB power, and Flipper-compatible firmware.",
 "tradeoff": "It lacks Flipper’s secret keys, so some sub-GHz protocols and U2F may not work, and it is sold as a development board rather than a finished product.",
 "tags": [
  "Flipper-compatible",
  "Sub-GHz",
  "NFC",
  "RFID",
  "Open hardware"
 ],
 "price": "€95",
 "priceShort": "€95",
 "priceFrom": "store.rainwalker.ee",
 "checked": "2026-09-17",
 "url": "https://gadgets.sh/devices/kiisu-v4/",
 "shortUrl": "https://gadgets.sh/kiisu-v4",
 "markdown": "https://gadgets.sh/devices/kiisu-v4.md",
 "image": "https://gadgets.sh/assets/kiisu-v4.jpg",
 "cutout": "https://gadgets.sh/assets/cutouts/kiisu-v4.webp",
 "shareCard": "https://gadgets.sh/og/kiisu-v4.jpg",
 "shops": [
  {
   "merchant": "Rainwalker OÜ",
   "label": "Preorder from Rainwalker OÜ",
   "kind": "preorder",
   "orderable": true,
   "url": "https://store.rainwalker.ee/products/kiisu-v4b?utm_source=gadgets.sh&utm_medium=referral&utm_campaign=kiisu-v4&utm_content=api",
   "note": "Taking orders now; the maker sets the ship date."
  },
  {
   "merchant": "Lab401",
   "label": "Buy from Lab401",
   "kind": "shop",
   "orderable": true,
   "url": "https://lab401.com/products/kiisu?utm_source=gadgets.sh&utm_medium=referral&utm_campaign=kiisu-v4&utm_content=api",
   "note": "In stock at Lab401 when checked on 2026-09-29."
  },
  {
   "merchant": "Rainwalker OÜ",
   "label": "Source repository",
   "kind": "repo",
   "orderable": false,
   "url": "https://github.com/kiisu-io/kiisu4?utm_source=gadgets.sh&utm_medium=referral&utm_campaign=kiisu-v4&utm_content=api",
   "note": "The maker publishes this as a project, not a product listing."
  }
 ],
 "specs": [
  {
   "group": "Cores and interfaces",
   "rows": [
    {
     "label": "Main and aux MCU",
     "value": "STM32WB55RGV6 main MCU (up to 80 MHz) and STM32G431CBU6 auxiliary MCU (up to 170 MHz)",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "Sub-GHz",
     "value": "CC1101 transceiver with an internal 433 MHz antenna and a pad for an external SMA antenna",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "NFC",
     "value": "ST25R3916 reader and emulator with a built-in antenna",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "RFID and iButton",
     "value": "125 kHz RFID reader and emulator with a built-in antenna, plus iButton reader/emulator pins",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "Infrared and Bluetooth",
     "value": "Infrared receiver and transmitter, Bluetooth LE, and a Flipper-Zero-compatible GPIO header",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    }
   ]
  },
  {
   "group": "Display, sensors and power",
   "rows": [
    {
     "label": "Display",
     "value": "128x64 OLED, SSD1306-compatible in SPI mode",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "Sensors",
     "value": "GXHTC3C temperature/humidity fitted; LSM303AGR accelerometer/compass, BME680 gas sensor and a VL53xxx ranger are user-solderable",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "Power",
     "value": "LIR2032 rechargeable cell (never CR2032), USB Type-C, or a user-wired external Li-ion with a MCP73831 charger",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    }
   ]
  },
  {
   "group": "Firmware and compatibility",
   "rows": [
    {
     "label": "Firmware",
     "value": "Ships pre-flashed with Kiisu firmware and can run most Flipper Zero firmware; a Kiisu fork and an aux-MCU companion firmware are published",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/README.md"
    },
    {
     "label": "Limits",
     "value": "It lacks Flipper Zero secret keys, so some sub-GHz protocols and U2F may not work; the maker is not affiliated with Flipper Devices",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
    },
    {
     "label": "Schematics",
     "value": "V4b schematics are published as a PDF in the repository",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20schematics.pdf"
    }
   ]
  },
  {
   "group": "Buying and licence",
   "rows": [
    {
     "label": "Price and stock",
     "value": "€95 including VAT on the official Rainwalker store, in stock when checked on 2026-09-29 (the store prices by visitor country; an earlier reading of €330 was its UAE-dirham price). Direct US shipping was disabled when checked on 2026-09-17.",
     "source": "https://store.rainwalker.ee/products/kiisu-v4b"
    },
    {
     "label": "Field kit",
     "value": "A V4B(R) field kit with board, 433 MHz SMA antenna, SMA and LiPo interfaces and a keychain is listed at €469",
     "source": "https://store.rainwalker.ee/products/kiisu-v4b-field-kit"
    },
    {
     "label": "Hardware licence",
     "value": "Hardware design files under CERN-OHL-S v2; documentation under CC BY-SA 4.0",
     "source": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/LICENSE"
    }
   ]
  }
 ],
 "docs": [
  {
   "label": "Maker documentation repository",
   "url": "https://github.com/kiisu-io/kiisu4"
  },
  {
   "label": "README at the reviewed commit",
   "url": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/README.md"
  },
  {
   "label": "V4b user manual and quick start (PDF)",
   "url": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20manual%20and%20quick%20start.pdf"
  },
  {
   "label": "V4b schematics (PDF)",
   "url": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/kiisu%20v4b%20schematics.pdf"
  },
  {
   "label": "Licence",
   "url": "https://github.com/kiisu-io/kiisu4/blob/340c8a0c78f4d86d2b8df69b8d3ea551057166c9/LICENSE"
  },
  {
   "label": "Official store listing",
   "url": "https://store.rainwalker.ee/products/kiisu-v4b"
  },
  {
   "label": "Field kit listing",
   "url": "https://store.rainwalker.ee/products/kiisu-v4b-field-kit"
  },
  {
   "label": "KIISU official site",
   "url": "https://kiisu.io/kiisu-v4br/"
  }
 ],
 "blueprint": {
  "openness": "schematics",
  "opennessLabel": "Schematics published",
  "summary": "Rainwalker publishes a schematic PDF and 3D case models (STEP/STL) for the KIISU V4B under a strongly-reciprocal open-hardware license, but no KiCad/Altium/Gerber PCB-layout source or BOM is included.",
  "files": [
   {
    "kind": "schematic",
    "label": "KIISU V4B schematics (PDF)",
    "url": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20schematics.pdf",
    "format": "PDF"
   },
   {
    "kind": "3d-model",
    "label": "KIISU V4B 3D model (STEP)",
    "url": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20model.step",
    "format": "STEP"
   },
   {
    "kind": "3d-model",
    "label": "KIISU V4B 3D model (STL)",
    "url": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20model.stl",
    "format": "STL"
   },
   {
    "kind": "manual",
    "label": "KIISU V4B manual and quick start (PDF)",
    "url": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20manual%20and%20quick%20start.pdf",
    "format": "PDF"
   },
   {
    "kind": "schematic",
    "label": "Previous revision KIISU V4A schematics (PDF)",
    "url": "https://github.com/kiisu-io/kiisu4/blob/main/previous/kiisu%20v4a%20schematics.pdf",
    "format": "PDF"
   }
  ],
  "repos": [
   {
    "url": "https://github.com/kiisu-io/kiisu4",
    "role": "hardware",
    "official": true,
    "license": "CERN-OHL-S-2.0",
    "stars": 146,
    "pushed": "2026-09-16"
   }
  ],
  "parts": [
   {
    "part": "STMicroelectronics STM32WB55RG",
    "role": "Main MCU (Arm Cortex-M4, BLE + 802.15.4 radio)",
    "datasheet": "https://lcsc.com/datasheet/lcsc_datasheet_1912111437_STMicroelectronics-STM32WB55RGV6_C401505.pdf"
   },
   {
    "part": "STMicroelectronics STM32G431CB",
    "role": "Auxiliary MCU (Arm Cortex-M4)",
    "datasheet": "https://lcsc.com/datasheet/lcsc_datasheet_2304140030_STMicroelectronics-STM32G431CBU6_C529356.pdf"
   },
   {
    "part": "STMicroelectronics LSM303AGR",
    "role": "Accelerometer/magnetometer (eCompass)",
    "datasheet": "https://www.lcsc.com/datasheet/lcsc_datasheet_1810010809_STMicroelectronics-LSM303AGRTR_C126671.pdf"
   },
   {
    "part": "Bosch Sensortec BME680",
    "role": "Gas/humidity/pressure/temperature sensor",
    "datasheet": "https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bme680-ds001.pdf"
   },
   {
    "part": "GXCAS GXHTC3C",
    "role": "Temperature/humidity sensor",
    "datasheet": "https://datasheet.lcsc.com/lcsc/2106071002_GXCAS-GXHTC3_C2837688.pdf"
   }
  ],
  "notes": "Verified via `gh api repos/kiisu-io/kiisu4/git/trees/HEAD?recursive=1`: schematics PDF, STEP/STL 3D models and a previous 'v4a' schematics PDF are present; no .kicad_*/.sch/.brd/gerber/BOM files anywhere in the tree. Repo license is CERN-OHL-S-2.0 (strongly reciprocal), confirmed via the LICENSE file. STMicroelectronics' own st.com datasheet pages could not be reached from this environment (connection hangs, not a genuine 404) despite being the canonical URL for these exact part numbers -- LCSC-hosted mirror PDFs used instead and confirmed with 200 responses. GXHTC3C datasheet is shared with the base GXHTC3 part (same silicon family) per LCSC.",
  "checked": "2026-09-27"
 },
 "sourceFiles": {
  "kicad": [],
  "models": [
   {
    "label": "KIISU V4B 3D model (STEP)",
    "format": "STEP",
    "url": "https://raw.githubusercontent.com/kiisu-io/kiisu4/main/kiisu%20v4b%20model.step",
    "page": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20model.step",
    "bytes": 15360025
   },
   {
    "label": "KIISU V4B 3D model (STL)",
    "format": "STL",
    "url": "https://raw.githubusercontent.com/kiisu-io/kiisu4/main/kiisu%20v4b%20model.stl",
    "page": "https://github.com/kiisu-io/kiisu4/blob/main/kiisu%20v4b%20model.stl",
    "bytes": 28662133
   }
  ]
 },
 "firmware": [],
 "chips": [
  "stm32wb55",
  "cc1101",
  "st25r3916"
 ]
}