WaterRower Link+

Description

WaterRower Link+ is a bluetooth module designed for any WaterRower with the S4 monitor. It provides all the functionality of the official WaterRower ComModule as well as many additional features.

Features

• Replaces WaterRower ComModule and External ANT+ Module
  • External ANT+ connection Works on M1 when using recommended cable (unlike the official ANT+ Plugin-In module!)
• Bluetooth
  • Bluetooth Fitness Machine Profile
    • Rower Data
    • Indoor Bike Data
  • Supports BLE HRMs
• ANT+
  • Fitness Equipment Profile
  • Supports ANT+ HRMs
• S4 monitor heart rate provider
  • Sends captured ANT+/BLE HR data for display on S4 monitor
• ANT+ to BLE HRM bridge
  • WRL+ will broadcast ANT+ HR data over BLE for use in apps that only support BLE. e.g. SuperNatural

Tested Software

• WaterRower Connect
• Holofit
• VZFit
• ZWift
• Garmin Fenix 6
• SuperNatural (HR only)

Hardware

Hardware design is available in the KiCad projects in this repo. There are two versions, breadboard and PCB. With the breadboard version, everything can be assembled using dev boards and jumper wires. ¹ Both solderless and soldered breadboards were tested and work. The PCB version requires the design be sent to a PCB manufacturer.

Soldered Breadboard Version

PCB Version

Breadboard Bill of Materials

Qty	Reference	Part	Foot Print	Supplier
1	C1	1uF	THT
1	C2	0.1uF	THT
1	J1	AudioPlug3	2.54mm	Amazon
1	J4	USB_A	2.54mm	Amazon
2	R1, R2	10k	THT	Amazon
1	SW2	Button	12mm	Amazon
1	U1	ESP32-S3-DevKitC-1	DIP	Amazon
1	U2	LM3525M-H	SOIC-8	Mouser
1	U2	SOIC-8 TO DIP		Amazon
1	U3	D52QD2M6IA2	2x10_2.54mm	Digi-Key
1		PCB Breadboard	50x100	Amazon
1	Project Box	B07W78LN1V	100 x 60 x 25	Amazon
1	TRS Cable	CC0377	3.5mm	Amazon
1	USB Cable	3896	Mini USB	Monoprice

PCB Bill of Materials

Qty	Reference	Part	Foot Print	Supplier
2	C1, C3	1uF cap	0603	Amazon
8	C2, C4, C5, C6, C9, C10, C14, C16	0.1uF cap	0603	(See above)
2	C7, C11	C 10uF cap	0603	(See above)
4	C8, C12, C13, C15	4.7uF cap	0603	(See above)
1	D1	SK6812	5x5mm	Digi-Key
1	D2	1N5819	SOD-323	Digi-Key
1	D3	RED LED	0603	Amazon
1	J1	Molex_67643	USB-A	Mouser
1	J2	CUI_SJ-3523	3.5mm	Mouser
1	J3	Molex-105017-0001	Micro USB	Mouser
1	Q1	BSS138	SOT-23	Mouser
2	Q2, Q3	S8050	SOT-23	Amazon
7	R1, R3, R4, R5, R6, R8, R11	10K res	0603	Amazon
2	R2, R7	1K res	0603	(See above)
1	R9	47K res	0603	(See above)
1	R10	22K res	0603	(See above)
1	R12	5.1K res	0603	(See above)
1	SW2	Header	2x2.54mm	Amazon
1	SW2	Button	12mm	Amazon
1	SW4	RESET	2x2.54mm	(See above)
1	SW1	RESET	6x6mm	Amazon
1	SW3	BOOT	6x6mm	(See RESET)
1	U1	ESP32-S3-WROOM-1	ESP32-S3-WROOM-1	Mouser
1	U2	LM3525M-H	SOIC-8	Mouser
1	U3	D52Q	D52QD2M4IA	Digi-Key
1	U4	CP2102N-Axx-xQFN24	QFN-24	Digi-Key
1	U5	AP7361C-33E	SOT-223	Digi-Key
1	U6	SP0506BAATG	MSOP-8	Mouser
1	Project Box	B07W78LN1V	100 x 60 x 25	Amazon
1	TRS Cable	CC0377	3.5mm	Amazon
1	USB Cable	3896	Mini USB	Monoprice
1	Light Pipe		RA	Digi-Key

Cable Connections

1. Attach mini USB cable to S4 monitor and WaterRower Link+
2. Attach 3.5mm cable to S4 monitor and WaterRower Link+. The recommended cable will fit in the narrow gap of an M1 rower and the monitor.
3. Attach micro USB cable to USB power supply

Required Software

• Visual Studio Code
• Visual Studio Code Espressif IDF extension
• ESP-IDF Built using commit 0132079fa51f2c130513dd634e97ef9726f00e85

Equipment Used

• Soldering Iron: YIHUA 995D+
• PCB Hot Plate: MINIWARE MHP30M Mini Hot Plate
• PCB Holder: Stickvise
• Microscope: AMScope SM745NTP-B + DAB

Usage

Once power is provided, a red LED will illuminate on the board and should be detectable in apps. Press the button connected to SW2 turn on the S4 monitor. The NeoPixel will illuminate green when it detects it over the USB connection. It will power off automatically after 30 minutes of inactivity. When WRL+ is receiving data from the S4, the LED will turn cyan. When it detects a heart rate over BLE or ANT+, it will beat red. Note the software only supports one HRM. If multiple are detected, only the first one seen will be connected.

Known Issues

• The last update to VZfit displays HR in the HUD however the value does not appear correct. It may be a bug with WRL+ or VZfit.

Credits

This project was inspired by PiRowFlow

Footnotes

1. The LM3525M must be soldered to the SOIC-8 TO DIP first ↩

2. This part is EOL at Digi-Key. I do not know if there is a compatible replacement. ↩