JJY transmitter for Raspberry Pi Pico W

Overview

This project is JJY transmitter for Raspberry Pi Pico W in proximate usage

This project supports:

• Fetch JST time by NTP
• Generate JJY signal
• JJY carrier frequency is configurable for 40 KHz or 60 KHz

About JJY, please refer to https://jjy.nict.go.jp/jjy/trans/index.html

Supported Board

• Raspberry Pi Pico W

Pin Assignment

Pico Pin #	Pin Name	Function	Note
3	GND	GND	Ground
4	GP2	PIN_MOD_P	JJY modulation differential output Pch
5	GP3	PIN_MOD_N	JJY modulation differential output Nch
6	GP4	PIN_CTRL	Control Output (option for external carrier generator)

• If single-ended output is required, use GP2 and GND.

Connection Diagram

How to make the program work

• Use Thonny or similar MicroPython IDE (Confirmed with Thonny 4.0.2, Python 3.10.9)
• Install MicroPython (Raspberry Pi Pico) interpreter firmware on Raspberry Pi Pico W by Thonny
• Confirmed with MicroPython v1.22.2
• Add secrets.py to include your WiFi configuration and put it on the storage of Raspberry Pi Pico W

# secrets.py
secrets = {
  'ssid': 'xxxx',
  'password': 'xxxx',
}

• Excecute pico_jjy_tx.py from Thonny
• For stand-alone application, please rename pico_jjy_tx.py as main.py and store in the storage of Raspberry Pi Pico W

Tips for emitting JJY

• The easiest way to make the clock detect JJY emulated singal in small room environment, is just to connect wired earphone between PIN_MOD_P and PIN_MOD_N pins and put the clock near the earphone cable. (This could damage the earphone. please try with cheaper one.)
• For the more proper way, round ferrite rod bar antenna with appropriate driver would be suitable.