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The EEPROM recorder is addressing the need for a low cost high performance and very robust wind measurements. This is a need for small scale wind power deployment. Small scale wind power is already a volume market most likely it will continue to grow.

• Affordable
• Swedish Design

Wind speed is crucial to pay off wind power investments and is the most critical factor for wind power deployment. The wind power is proportional to cubic factor of the wind speed. See:

http://www.awea.org/faq/windpower.html

The design goal for this project is to be high and enough quality but still cheap enough to address the need for small scale wind power. It's an impossible equation to spend lots of money just to get an idea about wind potential. Still wind data is crucial the design and implementation process.

Key features

• Lastest Lowpower Low-Voltage Technology CPU, EEPROM etc
• Powered by only two NiMh type AA cells.
• Logger unit (no anemometers) power consumtion about 20 uA.
• Integated PWM charge controller. Can be used with small solar panel.
• Rugged IP65 industurial housing. Custom PCB form factor.
• Long lasting EEPROM soldered on PCB. No contacts.
• Verbose monitoring via firmware.
• Scientific grade anemometer using very low power Hall Elements.
• Anemometer using sapphire and improved teflon bearings.
• One logger unit can support two anemometers.
• Logger has an open API for logging direct over USB to computer
• Easy plotting. IE gnuplot.

System components

• The EEPROM recorder/logger w. Powerful Atmel processor
• Low-Power Hall Anemometer. Very low-power HALL sensor
• A Small Solar Panel (Battery charge and light sensor)
• Custom USB-cable TTL-USB (FTDI)
• Cabling

Basic functions

The logger collects and processes the wind data from a anemometer and stores this in the EEPROM memory. The logger has it's own real-time clock which should be accurate within some minutes per year. The logger also has an integrated charge controller under software control and can use solar panel to charge the two NiMH AA cells. Connection is done via USB via a special cable and the collected the data is transferred to a host computer for further analysis.

Logger format

SMHI logger REF[SHMHI] is designed be compact representation and should be easy to understand and export for deeper analysis and Wind Turbine selection.

Logger connections

• Solar Panel. (Max 5 Volts). Terminal block.
• Anemometer. 2 Terminal blocks.
• USB-cable TTL-USB 6-pin connector.

Installation

Monitoring

The logger is equipped with three very lowpower LED's that indicates the logger status

Via LED (from outside inspection)

• Green LED.

  • Battery voltage is ok.
  • EEPROM is not full.
  • Pulses seen from anemometer.
  • Loggins is enabled (via firmware).
• Red LED. Logging stopped or fault condition
• Yellow LED. Warning wait for GREEN or RED
• Fast LED blinking interval indicates battery is charging

Via USB

See command summary.

Trouble shooting Roadmap

• Check monitor diodes
• Check NiMH cells voltage
• Connect to USB

API for data collection and monitoring via USB

The logger can be used with serial port over USB. To log or monitor data directly to an attached computer. The communication follows an API as today of revision 1.2. Communication can be done with program's tty_talk (linux) open source. Latest API Revison

Firmware commands

Expert mode. To be written.

Anemometer calibration

It's recommended to calibrate the anemometer as it's are a very crucial part of measurement system. Normally this is a very expensive operation. Requiring a wind-tunnel. An cheap alternative might be calibration with a good GPS and the anemometer mounted on the car roof. It's need to mounted so turbulence from car does affect the measurement. Also of course there should be no wind besides the speed-wind.

Car calibration anemometer mounting proposed by Pekka Kumpula

Logging speed on high-way

Statistical analyses to get anemometers transfer function

Low-Cost Anemometer Efforts

Also to mentioned is many years of work to get a anemometer to match price and performance needs to match price and measurement accuracy for small scale wind-power. A compromise was to rework and improve bearing etc of existing American anemometer and also equip the anemometer with Hall Element sensors. The anemometer is servicable and can bushrings and bearings can be repalced. Link to a stress test

UPDATE --- It didn't work out. HALL element can't keep up with frequency. A new ultra low power version of the anemomter is under test. New Low-Power body w. PCB

References and other resources

NRG systems have some useful guidelines for lightning protection. http://www.nrgsystems.com

NRG makes very good anemometers but cannot match our low-power and low-cost needs.

Index

Examples