NiRadio

NiRadio

Communication board with RPI2040 and SX1262 on base. Use low power to access long range.

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The NiRadio board consists of several parts and layers.

there are 4 copper layers.

1. GND filled layer
2. 3V3 filled layer
3. GND filled Layer
4. GNF filled layer

The core components of the board are SX1262 Radio Transceiver module and RPI2040 MicroController unit. Starting from SX1262 module. It required connection with crystall oscillator and 32MHz crystal was used and connected on pins SX_XTB and SX_XTA. Apart from that SX1262 frontend is done with low frequency pass filter for that reason PE4259 with combination 0900FM15K0039 parts were placed. Then there is an antenna. Next RPI2040 is connected to QSPI flash memory W25Q128JVS 128Mbit Apart from that it uses 12 MHz crystall oscillator. More about rpi2040 you can see in my NiroRPI-devboard repo The connection between SX1262 radio transceiver and RPI2040 is based on SPI protocol.

Another Important Aspect is powering. To get required 3V3 from 5V the AP2112K-3.3 stable regulator that allows to pass current under 600mA, which is more than enough for this board. The power delievered either directly through the board front copper layer 1, or through layer2 3v3.

To reduce the noise ferrite bead BLM15AX102SN1D was used. Power and data delivered through USB Type C receptable. Apart from than, Via fence and stitching can be seen all over the board. As it reduces the noise near the components, and provides stability.

Custom Features

• LiPo battery charging Using MCP73831 Chargin IC and Mosfet for power switching when USB C not connected, the mobility of pcb increased and it can be used by battery connected to JST 2pin connection.
• Oled I2C Support To output the incoming message or signal without external device as laptop, small display can be connected. For that 4 pin pinheader was added to pcb and GPIO 4 and 5 is accessible for I2C communication.
• Extra Push Button Finally, to make it really stand alone the extra input possiblity was added by push button. It can be coded for morse code or selection of static messages. Possibly, Bootsel button also can be used for input after loading the code.

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BOM

total: ~$51.3 (if bought seperate) and ~30 if to buy components in kit

Price doesnt include layer devboard production

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Scheme

• Pins and connections done using local labels.
• Scheme logically divided into 4 parts

1. SX1262 including its crystall oscillator, and pins
2. Frontend for SX1262 including antenna, Frequency filters etc
3. RPI2040 MCU including Flash Memory, crystall Oscillator, decoupling capacitors and buttons for run and reset.
4. Power including TYPE C receptable and 3V3 Regulator

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PCB layout

Front copper Layer and Back Copper Layer

( SilkScreen hidden )

front and back with silkscreen

3D view front and back

Thank you, hack club!