"low-power" refers to components and circuits which are designed to have a lower power consumption than their common counterparts. This is most often a requirement because of limited available power, as in battery operated devices.
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Why does a faster clock require more power?
If you overclock a microcontroller, it gets hot.
If you overclock a microcontroller, it needs more voltage.
In some abstract way it makes sense: it is doing more computation, so it needs more energy ...
16
votes
3answers
1k views
Making a battery last a long time in a microcontroller circuit
I'm hoping to power an ATtiny85V for a nice long time on some small battery, probably a coin cell.
I've looked into the software side, and my code is watchdog timer driven, has unused analog and ...
10
votes
11answers
755 views
Low power radio + microcontroller recommendation?
I'm searching for a low power system-on-chip that combines:
A processor (any achitecture)
A radio (any frequency/bitrate/tx power)
2 or more I/O pins (ADC would be a bonus)
Can anyone recommend a ...
10
votes
5answers
4k views
How can a let my atmega328 run for a year on batteries?
Scenario
I have created a nice electronic door lock for my dorm room. It is currently an Arduino Diecimila with a servo [un]locking the door. It has a numerical keypad with 3x4 buttons and 5 LED's (2 ...
10
votes
3answers
285 views
Microcontroller Sleep Race Condition
Given a microcontroller that is running the following code:
...
9
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7answers
2k views
LEDs on a (battery) budget! – How can I lower the current through a LED without using up the battery?
EDIT: Here is a much brief version, the meandering motivated version is probably subsumed in the parent question on general battery life optimizations.
How can I lower the current into a LED ...
8
votes
1answer
248 views
Is the Cortex M0 really low-power?
I'm using the NXP LPC1100 series CPU, which is their most low-power Cortex M0 offering. However, in the datasheet it states that under the most optimal conditions (sleep-mode + all peripherals ...
8
votes
1answer
186 views
LED current while off
I have a vague recollection that while off, a LED can actually receive light and generate a small current (in uA).
Is that correct? How does that work? What is the best way to prevent this?
8
votes
3answers
491 views
Do batteries last longer with constant current draw or spiky current draw?
Do batteries last longer with constant current draw or spiky current draw?
Or, as is implied by the accepted answer to
"Making a battery last a long time in a microcontroller circuit",
do some ...
7
votes
4answers
330 views
Do Linear regulators have a minimum current to maintain their output voltage?
When I was searching Digikey for a ~6V to 3.3V Linear regulators, there was a minimum current column in the listing results. This kind of threw me because I didn't know that there was such a thing, or ...
7
votes
2answers
393 views
Autonomously-powered (battery-less) wireless pushbutton
What would be a feasible approach/circuit-design to make a self-powered wireless pushbutton, assuming it is even realistic?
This is what I mean by each of the three terms:
Self-powered: Power ...
7
votes
3answers
151 views
How do I find energy leaks?
I'm in a process of writing software for eZ 430 Chronos watch using TinyOS. I want it to be as low-power as it is possible.
Unfortunately, my measurements show power consumption of about 350uA @3.3V ...
6
votes
4answers
1k views
Low power design - switch out voltage divider using transistor?
I have a very simple voltage divider circuit for measuring the resistance of a platinum 100 Ohm resistor.
I want to be able to switch out the voltage divider circuit from the power supply in order to ...
6
votes
4answers
530 views
How to cut power off when a certain voltage from a sensor is reached?
I've built a simple Ni-Cd charger (basically a 0.1C current source) for some 1300mAh cells, that I want to stop when a certain voltage is reached on the cell. I tried to design the switch with an Op ...
6
votes
1answer
3k views
Some advice on charging circuit used in simple UPS
I have looked around for some way of having a 5 volt power supply that acts like a UPS.
Basically want to use a micro usb connector for +5 have a battery and li-ion or other charging circuit that ...
6
votes
1answer
687 views
Minimum ATMega328 speed with UART
I am looking at designing a low-power project that will have an ATMega328 running at a low speed for lower power consumption.
The current plan is to have the UART hooked up to a RF Link Receiver for ...
6
votes
2answers
1k views
Bluetooth power saving mode for ArduinoBT
I'm trying to get my ArduinoBT to be a bit more power friendly, I have it running in a sensor network and it is constantly drawing power. I want to be able to turn off or put the Bluetooth module to ...
6
votes
1answer
263 views
Bluetooth vs Bluetooth Smart (Low Energy)
Im trying to decide between Bluetooth and Bluetooth LE. My device needs to transfer 375 bytes per second. Bluetooth LE can send packets of 20 bytes max, so this boils down to about 20 packets per ...
6
votes
4answers
212 views
Protecting Microcontroller Input Pins from Soft Power Switch
I'm working on a soft power switch for a microcontroller where a momentary switch can turn the circuit on (including microcontroller), and then when the switch is pushed a second time, the ...
5
votes
2answers
2k views
Efficient low power regulation? i.e. 9 -> 5 Volts
For the sake providing as much current as possible to a small circuit, regulated down from ~9V to 5V (or 5V->1.5V), I have looked at some possible options. What I was originally going to do (maybe a ...
5
votes
5answers
1k views
simple, energy efficient circuit to make single IR LED blink
I'm using a 850nm IR LED (spec sheet), and in order to extend my battery life, I'd like to make the LED blink (UF 1.9 V, IF 100 mA).
I found a couple of links 1, 2, 3 but they either a) require two ...
5
votes
3answers
127 views
Powering an IC from a GPIO line
I've got a low power application which will be powered from a Li coin cell. I've achieved satisfactory seeping current with my chosen MCU.
The application ADC IC however is a different matter: 900µA ...
5
votes
2answers
389 views
Low battery detection circuit that can tell if temporary voltage dip or actual low battery
I am currently using a schmitt trigger to turn off power to non essential circuits when the battery voltage dips below a certain threshold.
The problem with this circuit is that it is dumb, i.e., it ...
5
votes
2answers
197 views
What is the most power-efficient way to generate vibration in a small area?
I'm trying to generate a perceptible vibration (as felt against skin) in a roughly 4x4mm area. What's the most power-efficient way to do that?
5
votes
1answer
994 views
Low power micro-SD card storage
We are building a low-power data logger based upon the ATmega328P, in order to make use of the Arduino boot loader and IDE, etc. Ideally power consumption should be less than 0.3mA @ 3.3V to get ...
5
votes
5answers
157 views
How to determinate a reasonable clock frequency for a MCU?
Currently my datalogger is running at 12Mhz, and sleeps 90% of the time. When it's active its mostly blocked by I/O like SD-card or UART.
I suspect the system would still work at 6 Mhz, but how do ...
5
votes
1answer
355 views
Turning a microcontroller on with a flip flop
I'm working on debugging a circuit that I've built and am trying to wrap my head around an issue.
I have the following circuit (74LCV is an inverting flip flop and the NCP1400 is a boost converter):
...
4
votes
6answers
479 views
Which low power microcontroller for short active periods at long intervals?
Regarding this question.
In the question was asked for a solution for monitoring a voltage over a long time. The question contains hints to a microcontroller solution, and a couple of answers also ...
4
votes
5answers
212 views
Does CW or SSB consume more power?
CW pumps out the full carrier but has a better SNR. On the other hand SSB suppresses the carrier, and one side-band but this suppression demands additional circuitry. There are probably additional ...
4
votes
6answers
851 views
How to build an ultra-low power time counter?
Inspired by this question I would like to know how low power you could go with a counter + 32 kHz oscillator (possibly made by yourself).
I found a nice oscillator circuit on a BJT reportedly drawing ...
4
votes
3answers
258 views
How would you detect vampire/standby power?
Is it possible to detect when a device is consuming power in a stand-by or nominally off state? For example if I leave my charger plugged in, detect that a small amount of current is being drawn and ...
4
votes
2answers
407 views
How to choose a low power Microcontroller?
Cortex-M0+ from NXP and Freescale claim they have world leading energy efficiency.
TI Wolverine also claim they cuts power consumption in half and have the lowest power in memory, peripheral, standby ...
4
votes
4answers
474 views
Efficient low-power buck (step-down) regulator IC for Li-Ion - 3.3V conversion?
It's not easy for electronics novice to find good element base, so I hope this suitable question.
Requirement: Efficiently power a lean, 3.3V-based MCU design from a Li-Ion battery. "Efficient" ...
4
votes
1answer
159 views
Power Needed For Bluetooth Transmission
I'm developing a project that has a bluetooth module transmit to an android phone. The project is extremely power limited (it's energy harvesting) and I'm wondering how much power am I looking at to ...
4
votes
1answer
230 views
Isolation for microcontroller that is off
I have a design where power savings is a huge issue and even the lowest power sleep mode of the \$\mu\$C is too much quiescent current (30 \$\mu\$A). I'm aware of many and have used \$\mu\$Cs in the ...
4
votes
3answers
165 views
ways to generate (small amounts of) electricity
I'm searching into ways of generating very small amounts of electricity, by small I mean enough to light a couple of leds, nothing more
The main idea is to have toys that my daughters (2 and 4) can ...
4
votes
3answers
486 views
What is the best low-power color indicator?
The project I am working on requires a color indicator which shows the current state (either red, green, or yellow).
Ideally the indicator would have a large surface area so you can quickly glance at ...
3
votes
3answers
374 views
Suggest a timer chip
I need to take voltage measurements separated by long delays (couple of hours) and beep a buzzer when voltage level is met.
Power consumption is important.
What i want is a simple timer chip like ...
3
votes
4answers
617 views
Recomendation for a digital inverter made of discrete components
I have a digital circuit in which I need only one logic inverter, and both PCB size and power consumption are serious constrains. So I thought about using a pair of complementary SMD MOSFETs (the ...
3
votes
3answers
751 views
Waking Up From Deep Sleep Modes
Most microcontrollers (e.g. AVRs,MSP430s, PICs, etc) support a number of different sleep modes. The "deepest" sleep mode is the one that purports the lowest power draw (e.g. "Power Down", "Shut ...
3
votes
2answers
945 views
USB / Battery Switchover Circuit
Background: I am a non-EE (an 0x11? :^) thrust into the world of embedded systems design. I started this project with a only college physics-level understanding of circuits, but I'm gradually ...
3
votes
2answers
83 views
Power switch for a dive computer
I am creating an open source dive computer (www.diydivecomputer.com) and I am having a little bit of a problem trying to figure out how to power the device on and off. The problem is that the device ...
3
votes
2answers
283 views
Are there any commercially available crystals in the sub 32 kHz range?
I'm looking for a low power clocking solution and it looks like crystals bottom out at 32 kHz. Are there any low power (nA) solutions (crystals/ceramic resonators/custom transistor oscillator ...
3
votes
4answers
92 views
What happens to other component's power consumption, when uC is switched to low-power mode
Currently, I am using a uC (Atmel ATtiny85-PU20), which will eventually run battery powered, and I am trying to reduce power consumption of entire circuit to maximise time between battery changes. ...
3
votes
3answers
285 views
ultra low noise reference and supply voltage with multiple ldo's in parallel
I need a very low noise power supply and ADC reference voltage for an 24 bit ADC measurement (I need noise level less than 5 uV peak to peak on both power supply and the ADC reference voltage. Supply ...
3
votes
1answer
316 views
What is the current draw of an Arduino Due board when sleeping?
I have application which requires 1 year+ operation on a small battery (2xAAA or coin cell). It will be spending 99.99% of the time sleeping only requiring an internal timer for periodic waking and ...
3
votes
3answers
406 views
Tips on parts for a very low power LED blinker
I'm looking into designing a badge for a tech conference and we're thinking of creating a small PCB with one or more LEDs on it.
Requirements:
Less than $5 per unit for 2500 badges
The PCB has to ...
3
votes
1answer
131 views
Can an unpowered 2.4ghz transceiver exist?
I just read an internal presentation from the company i work for announcing the release of a small consumer device with an embedded RFID tag and 2.4 GHz transceiver. The presentation made note of the ...
3
votes
1answer
108 views
Guidelines for sizing solar-powered electronics?
Does anyone know of sizing guidelines or calculators for solar powering electronics? i.e. given power consumption, latitude and allowing for bad weather, accumulated dust and bird poop etc, calculate ...
2
votes
2answers
106 views
How to disconnect a component with a microcontroller output?
I have a circuit that uses a PIC microcontroller and an OpenLog from Sparkfun (a microSD card logging module ). Everything is running at 3.3V.
In order to conserve power when it is not in use, I ...
