SCK-915 Explorer Kit

Overview

The SCK-915 Explorer Kit is a complete RF communications development kit based on the open-source OpenLST radio platform originally developed by Planet Labs. The kit includes two CC1110-based radio boards operating at 437 MHz and a Windows ground station application for commanding, monitoring, and imaging.

With the Explorer Kit you can:

• Send and receive commands between a ground station and a remote radio board over RF
• View real-time telemetry including uptime, signal strength, and ADC readings
• Trigger a remote Raspberry Pi Pico to capture images with an Arducam OV2640 camera
• Transfer JPEG images from the remote SD card back to your Windows PC over RF
• Build and flash custom firmware to the remote board
• Provision new boards with the bootloader and hardware IDs

What's in the Box

Installation

First Launch

When you first launch the application you will see the main window with tabs across the top. Settings are automatically saved between sessions including your COM port, baud rate, HWID, firmware directory, and AES key.

Hardware Connections

Board 0001 — Ground Station Radio

Board 0001 connects to your Windows PC via the USB-serial adapter and relays all RF commands to board 0004.

Board 0004 — Remote Radio

Board 0004 is the remote unit. It communicates with board 0001 over RF at 437 MHz and optionally connects to a Raspberry Pi Pico for imaging.

Power Requirements

Raspberry Pi Pico Wiring

The full imaging setup requires a Raspberry Pi Pico with an Arducam OV2640 camera and SPI SD card adapter. All three share the Pico's SPI0 bus with separate chip select pins.

Connecting to the Radio

The connection controls are in the header bar at the top of the application window.

1. Select your COM port from the dropdown (click ↺ to refresh the list)
2. Baud rate should remain at 115200
3. Set the HWID to the board you want to address (e.g. 0001)
4. Click Connect

The status indicator in the header turns green when connected. The application will begin receiving any data from the board immediately.

Home Tab

The Home tab shows live telemetry from the currently addressed board, updated automatically every 5 seconds when connected.

Telemetry Panels

Commands Tab

The Commands tab provides quick access to all standard SCK commands.

Available Commands

All commands are sent to the HWID shown in the header bar. To address board 0004 remotely, set HWID to 0004 — board 0001 will relay the command over RF automatically.

Custom Commands Tab

The Custom Commands tab lets you send any opcode with any payload to the addressed board. Commands are saved to a JSON file and persist between sessions.

Pre-loaded Pico Commands

On first run the following commands are automatically available for controlling the Raspberry Pi Pico payload:

Sending a Command

1. Select a command from the left panel, or fill in the Name, Opcode, and Payload fields on the right
2. Set HWID to the target board in the header bar
3. Click ▶ Send

Responses appear in the main log panel. Pico ASCII responses are decoded automatically:

Files Tab

The Files tab provides a complete SD card file manager for the remote Pico. It allows you to list, download, and delete files stored on the Pico's SD card — all over RF.

Refreshing the File List

Click ↺ Refresh List to request the current list of files from the Pico's SD card. JPEG and text files are shown. The request is sent over RF to board 0004 which forwards it to the Pico.

Downloading a File

Deleting a File

Select a file and click ✕ Delete File. A confirmation dialog will appear before the file is permanently deleted from the SD card.

Firmware Tab

The Firmware tab is used to build, sign, and flash custom firmware to the radio boards. This tab is primarily for developers — standard users do not need to use it.

Build

1. Set the Project Dir to your SCK firmware source folder (the folder containing the top-level Makefile)
2. Click ⌧ Clean + Build to ensure a fresh compile
3. Build output appears in the log. A successful build ends with Build succeeded: openlst_437_radio.hex

Flash OTA

1. Set HWID to the board you want to flash (e.g. 0004)
2. Ensure the HEX file path is correct (auto-filled after a successful build)
3. Verify the AES key matches the key used when provisioning that board
4. Click ▶ Flash OTA

The flash process has three phases: entering bootloader mode, writing pages, and sending the end signal. Progress is shown in the log with page numbers and attempt counts.

Provision Tab

The Provision tab is used to program the bootloader onto a fresh CC1110 board using the Texas Instruments CC Debugger hardware programmer. This is a one-time operation required for new boards.

Requirements

• Texas Instruments CC Debugger connected to the board's programming header
• SmartRF Flash Programmer installed (included with the CC Debugger)
• The bootloader HEX file (openlst_437_bootloader.hex)

Provisioning Steps

1. Connect the CC Debugger to the board and your PC
2. Enter the desired HWID (e.g. 0001 for the ground station board)
3. Enter the AES signing key (default: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
4. Browse to select the bootloader HEX file
5. Click Flash Bootloader

Log Format Reference

The main log panel uses a consistent color-coded format:

Troubleshooting

No reply to Get Telem on board 0001

• Check the USB-serial adapter is connected and the correct COM port is selected
• Verify TX→P0_5 and RX→P0_4 (not swapped)
• Confirm the external 5V power supply is connected to board 0001
• Check the board LEDs — rapid double-flash indicates bootloader mode; flash the radio app

No reply to Get Telem on board 0004

• Confirm board 0001 is responding first — it must relay commands over RF
• Ensure the boards are at least 2 feet apart — too close causes RF overload
• Check board 0004's power supply
• Try sending Get Telem 2–3 times — the first packet after boot is sometimes missed

PICO commands return no reply

• Wait 5–10 seconds after the Pico boots for camera initialization to complete
• Verify UART wires between board 0004 and Pico (P1_5→GP1, P1_4→GP0)
• Check the Pico is running main.py (connect Thonny to verify)

SNAP returns error

• Check camera wiring — must be direct wire, not breadboard
• Verify SD card is inserted and formatted as FAT32
• Ensure SD card adapter VCC is connected to VBUS (5V), not 3.3V

File transfer shows wrong image

• Click Refresh List before downloading to ensure the file list is current
• Check the Images folder path shown in the transfer status log

Board resets during RF transmission

• The external 5V power supply must be connected — USB power alone is insufficient
• Add a 100µF electrolytic capacitor across the board's power supply pins to absorb the transmit current spike

Specifications