Home About Blog

Radio Board v1

From Snowcap

Jump to: navigation, search

Status: Completed


  • One design, two applications
    • Application 1: Radio for Control board
    • Application 2: Standalone wireless sensor
  • Provide xBee replacement for Control Board v2
  • Standalone MCU with RF for home automation
  • Dash7, if suitable, for general interest (too complex for now)
    • CC430F5137 is supported by OpenTag M2 though.

Related docs


Radio board v1 gerbers
Radio board v1 3D view in Kicad
Radio board v1 schema


Ref Value Digikey ref
C1, C3, C5, C6, C8, C10, C11, C14, C15, C22 100nF 490-1318-1-ND
C2 470nF 445-4989-1-ND
C4 10 uF 445-1371-1-ND
C7, C9 30 pF 445-4902-1-ND
C12, C13 2 pF 445-4862-1-ND
C16, C18 3.9 pF 490-1272-1-ND
C17, C21 220 pF 490-1293-1-ND
C19 8.2 pF 445-4892-1-ND
C20 5.6 pF 490-3103-1-ND
L1, L2, L4 27 nH 490-2628-1-ND
L3 22 nH 490-2627-1-ND
R1 56 kΩ 311-56.0KLRCT-ND
R2, R3 4.7 kΩ 311-4.7KJRCT-ND
U1 CC430F5137 296-25330-5-ND
X1 26 MHz 535-11297-1-ND
CN1, CN2 2mm header N/A
CN4 antenna N/A

Application 1: Control Board Radio

Provide fast long range radio communication between two Control boards or between a Control Board and a standalone MCU with RF.


  • CC430F5137 with 433MHz (4K ram, 32K flash)
  • TMP275 not assembled on the board
  • Same socket as xBee, 2x 10pin with 2mm pitch
  • Power pins
  • Spy by wire
  • UART pins
  • SPI
  • Radio can wake up control board via WAKE-UP pin
  • Control board can wake up radio via several GPIOs

Application 2: Standalone wireless sensor

Provide a very low power wireless temperature sensor.


  • CC430F5137 with 433MHz (4K ram, 32K flash)
  • TMP275 assembled on the board
  • No regulators, no charging
  • Needs SW for monitoring input voltage and to sleep if below specified threshold
  • Sleeps >99% of time for power saving
  • Extra GPIO and analog pins for other use cases than the TMP275


  1. SMA antenna ground not connected to ground
  2. nRST doesn't have pull-up resistor
  3. Crystal ground not connected to the ground
  4. (enhancement) cc430 pads are too small for debugging purposes
  5. SMA antenna bottom side ground pads missing


Device Center Frequency Amplitude Notes
1st proto 433.994 -8.7dBm
2nd proto 433.997 -7.4dBm
#1 433.937 -6.2dBm
#2 433.941 -7.9dBm P1.2 broken
#3 433.940 -8.1dBm
#4 433.937 -6.7dBm Does not honour debugger anymore
Tx -> Rx
#3 #1 ok
#3 #2 ok
#3 #8 ok
#3 #9 ok