low power computing
reduction of consumption
- low power components
- less moving parts.. , etc+
- electron conservation
power
microcontrollers
- atmel “PicoPower” range: http://www.atmel.com/products/AVR/picopower/Default.asp
data transmission
for remote sensors, recent technologies like wifi (802.11) or bluetooth are often considered. some examples of power consumption:
- this power optimised 802.11 module aimed at mobile devices, consumes 150mA (http://www.analogzone.com/hfp_0627.htm)
- this bluetooth module consumes “less than 30mA” (http://www.ezurio.com/products/at/)
- a module supporting zigbee, a low power bluetooth-like protocol consumes ~18mA in tx or rx mode. possibly to be in both modes at once it takes double? (http://atmel.com/products/avr/z-link/)
however, when only transmission is required, there are RF transmitters that seem much more efficient
- this RF AM transmitter module draws only 6mA while transmitting. (http://www.abacom-tech.com/data_sheets/ATX-433-IAuser.pdf) however, there is often only a choice of 3 or so different frequencies, which will raise problems when there are multiple sensors transmitting at once. the transmitters used in remote controlled cars somehow get around this (multiple channels per car, multiple drivers per race), how? (as in, is it possible to use get the modules on their own?)
cables vs air
- microchip (makers of the PIC) have a single chip ethernet driver IC (ENC28J60) that can do 10mbps. surprisingly, this consumes 250mA during normal operation. so, over the kinds of distances where cables appear to be a possibility, wireless is probably going to use less power.
- on the other hand, if you can handle doing serial, the max232 serial driver IC consumes about 10mA.
measuring
any research into low power electronics would need some method of measuring power consumption. a simple multimeter can measure current drain at an instant, but with most computing devices, the drain varies over time (changing sleep modes etc). what would be good is either a device that can measure the average current drain over a longer period of time, or even better, to graph the power drain. there are many digital multimeters with rs232 interfaces and some that are supported under linux.
- the cheapest i have found so far is the McVoice M-345pro. this is supported under linux by the latest version of QtDMM (according to the Changelog » http://www.mtoussaint.de/qtdmm.html#changelog).
- also the Voltcraft VC-820 (and other, more expensive Voltcraft models) are comparatively cheap and supported by QtDMM? (i have one now, thus ending my loggable-dmm acquisition obsession).
Libarynth > Main Web > LowPowerElectronics r9 - 31 Mar 2007 - 22:40
nik