WindLcdMeter

intro

this is a simple interface to the windmill power storage. there is be a button that the user toggles to get the current voltage and percent charge on the stored energy in the windmill battery(s). to conserve power the unit is controlled by a toggle switch rather than always be on; we work hard to generate that power - no point in throwing it away. this meter interfaces to my brothers beta windmill and soon to his 400W windmill.

embedded

this system is centered around an ATmega32 which is also the core of the AvronicsKit. using the onboard ADC the system samples the voltage across the inputs (attached to the windmill battery). The voltage reading (as a hex number from 0x0 to 0x3ff) is converted into a binary coded decimal (BCD) percentage and voltage and then displayed on the LCD.

the LCD uses a common hd44780 compatible controller but requires 8+3 I/O lines (8 data, 3 control). in this case it's fine because the ATmega32 is much more powerful than what is needed.

• hd44780.h: hd44780 control functions in a retargetable format

hardware

the system will read an analog signal from 0 to 15V but the ADC actually sees 0 to 2.54V thanks to the on board voltage divider. this meter simplifies the useage of the pepito (Makeinze) windmill. the battery is wired up to the terminal block on the front allowing the meter to monitor the charge on the battery. the meter also aquires it's power from the battery and is thus entirely green fueled!

parts

vendor	part type	part number	price
Newark In One	enclosure	07H3027	$5
ebay	20x4 LCD	N/A	$10
avronics.com	avronics mainboard	N/A	?

result

the software is completed and works well. the case has been dremeled and assembled and only some minor tweaks will be needed from here on out.

see more pictures at flickr

-- ChristopherPepe - 22 May 2006