New! WXLink Product Released for Mini Pro LP Arduino Board

The WXLink Wireless Weather Sensor Link product has been released and available for sale on the SwitchDoc Store.   Contains Grove Connectors so there is no soldering required.

What is the WXLink?

The issue is sometimes you don’t want to run a wire all the way from the Weather Station to the wind and rain sensor.  Using the Mini Pro LP, we built a WeatherRack reader and then we use a transmitter to send it back to the GroveWeatherPi station inside.

The WXLink product kit contains two Min Pro LP Arduino boards, a WXLinkWR Weather Rack Interface board, two transceivers and one DS3231 RTC Board.

The system has a bi-directional serial link between the two Mini Pro LP Arduino Boards.    The software below only supports a one way link, but you can modify the software code to transmit anything you would like.   The boards come preprogrammed with the Rx and Tx software so you can get up and testing quickly!

The Rx board has an I2C interface built in so it can be easily read by many computers without consuming the standard serial port.

WXLink Wireless Range

The Serial RF Pro is rated for 600 meters in free air.  Free air means with no obstruction and line of sight.   Anything in your way reduces the received power and reduces the range.   To test the range, We took the solar powered transmitter system on a walk down to the Spokane River.  We ran two tests.  One with the receiver behind three interior walls and one exterior wall and then repeated the test with the receiver only behind one interior wall.   We specifically looked for continuous data flow.   We found we could go about 5% or 10% further and still get a packet now and again.

Table 1 – Maximum Transmission Distance

Receiver Condition	Maximum Transmitter Distance
Behind 3 Interior / 1 Exterior Wall	220 meters / 720 feet
Behind 1 Exterior Wall	438 meters / 1437 feet

 

Downloads

• Specification and Assembly Manual
  
• Receiver Software – https://github.com/switchdoclabs/SDL_Arduino_WXLink_Rx
• Transmitter Software – https://github.com/switchdoclabs/SDL_Arduino_WXLink_Tx

Wiring Diagram

No soldering needed!  Plug and Play.

 

Data Format

Transmitted Data Format
Value	Format	Notes	Byte Value Start	I2C Block Number
Start Byte #0	0xAB	Constant	0	0
Start Byte #1	0x66	Constant	1	0
Wireless ID/Software Version	Byte	WIRELESSID is changed if you have more than one unit reporting in the same area.  It is coded in protocol as WIRELESSID*10+SOFTWAREVERSION	2	0
TimeStamp	long – 4 bytes	Approximate Seconds since reboot of TX unit.  Only guaranteed to advance with time.	3	0
Wind Direction	int – 2 bytes	degrees	7	0
Average Wind Speed (KPH)	float – 4 bytes	KPH	9	0
Wind Clicks	long – 4 bytes	clicks since last packet generation	13	0
Total Rain Clicks	long – 4 bytes	Since boot up	17	0
Max Wind Gust	float – 4 bytes	KPH – Not Implmented	21	0
Outside Temperature	float – 4 bytes	Degrees C	25	0
Outside Humidity	float – 4 bytes	%	29	Split between 0/1
Battery Voltage	float – 4 bytes	Volts	33	1
Battery Current	float – 4 bytes	mA	37	1
Load Current	float – 4 bytes	mA	41	1
Solar Panel Voltage	float – 4 bytes	Volts	45	1
Solar Panel Current	float – 4 bytes	mA	49	1
Aux A	float – 4 bytes	For future use	53	1
Message ID	long – 4 bytes	Increments from 0 at boot up sequentially per message packet generated and sent	57	1
Checksum High	Byte	High byte of CRC 16XModem checksum of message – see code for generation	61	1
ChecksumLow	Byte	Low byte of CRC 16XModem checksum of message – see code for generation	62	1
Fill byte	Byte – 0x00	constant	63	1

The Arduino Mini Pro LP Board

Features

• – Really Low Power Usage (for Solar applications!)
• – Grove Connector Compatibility for IOT Prototyping
• – ATmega328P Processor
• – Arduino Pro Mini Compatible Pinout
• – Under 1mA sleep current
• – DS3231 Real Time Clock Included
• – 3.3V – 5V
• – Arduino IDE Compatible
• – Thousands of drivers available
• – Compatible with Hundreds of Grove Sensors

And this is why we are building the Grove Pro Mini LP.

We redesigned the Arduino Pro Mini LP board to be very low power.   We removed the regulating power supply, modified the circuit to run the processor at 8MHz and provided 3.3V and 5V compatibility. Whew!  And the engineering prototypes work!  We have about another week of testing and we should be able to release to production.  That means we will should ship this Kickstarter on time!

A Low Power Arduino Board – Designed for Solar!

The Arduino family of processors is a fabulous prototyping and building system for Makers.   The combination of the Arduino IDE with its thousands of available drivers for sensors and the ATMega line of processors have spawned a tremendous burst of creativity around the world.

At SwitchDoc Labs we have been building and writing about Arduino projects for years.   From Project Curacao in the tropics to specialized Arduino based solar powered weather stations, we have extensively used these devices in many ways.

Low Low Power

The Grove Mini Pro LP is designed to be low power.   Especially when sleeping.   It can be awakened in a number of different ways.   The included DS3231 Clock can be programmed to wake up periodically, the Arduino can be programmed to sleep for a while then wake up and the board can be programmed to wake up on a GPIO line changing thus causing an Interrupt.  Very flexible.