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Questions tagged [low-power]

Low-power refers to electronics that are designed to use less power than their common counterparts. This is often a requirement because of limited available power, as in battery operated devices, or in cases with limited cooling capabilities, as in notebooks.

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23 views

Low power flashing led with phone battery

I want to make a circuit that flashes a series of leds and that lasts as long as possible from a tablet battery. The battery has a voltage of 4.2 when fully charged and 3.8 when discharged, and has a ...
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1answer
88 views

Where do I place the on/off switch in a multi voltage circuit?

I've got a simple Arduino setup where I need to supply a 3.3V Arduino with adequate power - and at the same time provide higher voltage to a sensor which needs 5V. The Arduino is powered by bypassing ...
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1answer
85 views

DC Current Measurement (resolution of ~ 1 uA)

I haven't worked with electronics in a long time, and now have the task of measuring the power consumption of a low-power device I'm writing firmware for... When the device is drawing very little ...
7
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4answers
850 views

What's causing this power spike in STM32 low power mode

I'm using an STM32L073RZ on a bare board with just the CPU and decoupling caps. I'm powering the board straight from an Otii Arc and measuring current consumption. I'm running MbedOS 5.11.2. When I ...
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3answers
285 views
+100

How to debug current consumption with STM32 Nucleo board?

I'm trying to configure an STM32L011-Nucleo developement board to consume about 600 uA of current or so. It uses an STM32L011K4. The datasheet states that this should be possible if I drive the MCU ...
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3answers
78 views

Power small microcontroller from motherboard RJ45 ethernet port

I'm wondering if it's possible to power a microcontroller (e.g. ATmega328) from a Ethernet RJ45 motherboard port. Unlike USB, there is no power line, all pins/lines seem to be data only. I am ...
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0answers
31 views

STM32 L0 wake from STOP mode with WAKEUP pin

I am attempting to wake an STM32L073RZ from stop mode using WAKEUP_PIN_1. I'm running MbedOS 5.11. Unfortunately throughout all of the documentation (Mbed/STM) I ...
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0answers
35 views

stm32f4 low power mode [closed]

I am using stm32f4 discovery mode with FreeRtos 2. Two task are implemented: uart task which interrput on some data receive from uart second task is sd card which write data every after 15 min ...
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0answers
29 views

Data communication in power harvesting project

I want to design a wearable gadget for elderly to detect falling. This gadget should work by energy harvesting. Now I want to find the best effitient way of power consumtion to send data to a station ...
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1answer
39 views

Low power device with high current peak

I'm creating power supply for controller that usually operates with very low power consumption, but sometimes needs high power. To make the situation harder there is "sometimes" external power present ...
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1answer
40 views

Harvest energy from ultra low current and high voltage source?

I have a sensor which can produce voltage upto 10 V but can only produce 50 nA of current. I tried to harvest energy using TI's BQ25570 evaluation board but the current is too low to kickstart the ...
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0answers
25 views

Power off detection circuit to close opened latching solenoid valve

The image above is referred from this SO link. My use case is the following: A latching solenoid valve, which would be run using 4 AA batteries (6V) Solenoid Valve (9 Ohm) operates at 6V under 40ms ...
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1answer
46 views
+50

MSP430FR5994 SVSH Interrupt from LPMx.5

Background: I plan to use lpmx.5 under cap power but need a way to save the rtc registers to FRAM when the super-cap runs down. Plan: Use SYSRSTIV SVSH interrupt to wake up and save the counter, or ...
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1answer
97 views

Lithium thionyl chloride for GSM application

I'm trying o use a LiSoCl2 battery in a low power GSM application. When the system is in standby only the microcontroller(MSP430) is powered(3.3v) and the GSM(5v) and sensor(5v) is turned off. The ...
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0answers
54 views

Ultra low power battery

I am currently in the middle of a project and I am quite unsure of what type of battery and battery charger I should be using. To be honest I have never worked with battery or battery charger yet. In ...
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2answers
88 views

Can transformerless power supplies be UL/CSA certified and is there any specific standard they must meet?

I am trying to bias a linear optocoupler on the AC mains side of a circuit, in order to transfer analog information to the secondary side of the circuit. I have designed the following capacitive power ...
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0answers
38 views

Ultra Low Power, LDO Enable from RTC vs. deep sleep MCU interupt

I have a question regarding optimising design for ultra low power consumption device. I'm trying to develop a remote sensor node that should measure and send data every few hours. Currently I have an ...
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2answers
71 views

Low idle power consumption for USB PSU

I'm trying to find out how "good" 5V power adapters can be with respect to power consumption if: there's no attached power consumer, and/or the consumer takes very little power, such as an ESP32 in ...
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0answers
37 views

Measure low AC Power consumption (oscilloscope? MCU?)

I would like to measure AC power consumption of devices such as AC/DC charger, AC LED bulb or an electric circuit in the main box of a house. However, their power consumption are quite low and the ...
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0answers
45 views

ESP8266-01S OFF State (CH_PD at LOW) Draining too much current

I have this project in which the life of the battery is imperative, after various designs i came up with this one: As you can see the pushbutton labeled START puts the CH_PD pin on HIGH for a brief ...
0
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1answer
63 views

USB and coin cell battery switching

I'm trying to do a simple, low power, low cost power "switch" for a custom board (I know, it will be complicated). The device will be powered by default by a coin cell battery (3V3 and lower) and can ...
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3answers
80 views

74HC4060 lower frequency limit

I need to sequence some micropower (low-microamp range) logic at a once-per-several-minute rate, and am falling back on the good ol' 4060 as my timebase (plus a 138 and a 534 for the sequencing). I ...
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2answers
91 views

Very low current (<10 microamps) darkness detector circuit that turns off in light

I've made a device that lights an LED at a very low current (<10 microamps) as a very dim indicator for use in the dark. At its simplest, the circuit is a 3V coin battery + resistor (300K-1M ...
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2answers
73 views

Avoiding DC voltage drop for surveillance cameras over long distances

Trying to power 2 HD-TVI cameras 800 ft away from my home office. The wall mounted adapter provides 12v DC at 1 amp. I am looking for a good solution at the lowest possible cost. There are ...
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1answer
52 views

How to condition supply voltage for project

I am working on a circuit that is powered by a regulated 5V external power supply. However, since I will be directly powering a Micro-Controller from this 5v supply, I was wondering how I should '...
2
votes
1answer
80 views

ATSAMR21 sleep high current draw

I have an ATSAMR21B18-MZ210PA, which is an ATSAMR21E18 packaged with MX25L2006E flash. The SAMR21 is itself a SAMD21 paired with an AT86RF233 wireless module. So that's a SAMD21 + low power wireless + ...
2
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1answer
50 views

Reset pulse generated by UART break condition

I'm trying to create a reset pulse triggered by external inputs to my circuit. My circuit is connected to an external 5V supply and TTL level UART (actually a half-duplex single line). I would like ...
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2answers
96 views

Power consumption NeoPixels vs. direct control?

At Maker Faire Berlin 2018, an electrical engineer looked at my project which was shown with NeoPixel LEDs (WS2811). He mentioned that the NeoPixels waste a lot of energy. It would be better to build ...
2
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0answers
63 views

Arduino-like microcontroller with more ram for image processing [closed]

I want to build a device to perform image acquisition and processing, but I don't know which kind of board/microcontroller to use. My idea is to use a low-res camera, take a shot, analyze it and ...
2
votes
1answer
70 views

Low-Power over USB [closed]

I have a small custom 5V 2mA device which is powered over USB. To be specific, it will be powered over USB by connecting it to an Android smartphone or an iPhone. There is no data transfer. I ...
0
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1answer
50 views

How to safely connect USB to TTL (FTDI) adapter to device and also use bench power supply?

I'm trying to flash new firmware onto an ESP8266EX chip. The chip requires 3.3v and 80 mA (average). My USB to TTL programmer (FTDI chipset) can supply 3.3v but only at 50 mA. Here is what I'm ...
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3answers
67 views

digital current monitor/sensor for monitoring ~0.1 uA to mA current from a MCU and sensor [closed]

Hello I am in need of a current monitor/sensor like INA219 for monitoring current in the range of 0.1 uA to ~ mA. Kindly suggest a way to monitor current in such lower range. I have a microcontroller ...
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2answers
59 views

Buck Boost Battery 3.6V (Lithium-thionyl Chloride) to 5V

I hope this question has not been asked and it's not as far as I have seen. I am developing an IoT project which uses almost no current (< 100uA) when sleeping and up to 80mA when running. The ...
2
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3answers
152 views

Driving a LED in the most energy efficient possible way [duplicate]

I got into a bit of a challenge with myself, just for the sake of learning something about low power stuff. I want to build a device that has basically two requirements: blink an LED every 5-10 ...
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1answer
118 views

Ver2.0 SDHC Card long response time after ACMD41 during initialization

I would like to implement a very low power SD card handling with MSP430 processors. I would like to log measurement data onto SD card without a file system. I want to turn on and off the SD card power ...
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1answer
78 views

Which is most used Barrel Connector ID? 2.1m or 2.5mm?

I'm working on an project which will be given to some friends and will be open-source too. I need to choose the power supply connector (5V or 12V @ 3A) and I'm thinking to barrel connectors. I found ...
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0answers
39 views

Help required to design a suitable energy harvester for TENG

So I am in the process of desgining a scalable Triboelectric Nanogenerator(TENG) through which I can easily harvest and store electricity in a battery or a capacitor. A TENG can be modelled as voltage ...
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1answer
117 views

3W infrared LEDs not living up to 500mA-700mA - not even close

Here are the specs: Emitted Color: 850nm Forward Voltage (VF): 1.5-1.7V DC Forward Current (IF): 500-700mA Maximum Pulse Voltage: 2.2V List item But after hooking to power supply (which I first ...
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1answer
44 views

Deep power down mode in LPC17xx

I am currently working on a home project. I want to put my LPC1769 in deep power down mode. this is the code I have so far: ...
3
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4answers
289 views

Do voltage dividers waste battery?

I am attempting to make a battery powered alarm clock with an Arduino, and I would appreciate some help on the circuitry part. I am very inexperienced with electrical engineering. I am using a ...
0
votes
1answer
77 views

Low voltage LCD glass displays

I have a simple circuit I built using a 7-segment LCD glass display and an ATTiny (just a simple timer for now). I was hoping to use the setup in a low power, single coin cell device (3.3V - 2.7V), ...
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1answer
83 views

Simple way to create a disturbance on DC power

First of all, i must say that I am a software engineer, with very-low to no experience in circuits designs, and a very rudimentary understanding of electrical engineering and circuits. 101 really. ...
9
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1answer
1k views

Why does this microswitch datasheet specify a minimum load current? [duplicate]

The Omron VX series datasheet mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro ...
2
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2answers
175 views

Powering a circuit from either USB or LIPO

I have a small hobby project which includes MCU and some peripherals. It is powered by 3.3V power source and consumes 200mA-800mA for up to a minute. However, most of the time it's in deep sleep mode ...
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5answers
9k views

How could have Banksy kept an RF receiver running for 12 years? [closed]

I'm talking about Banksy's "Girl with balloon" painting that shredded itself at auction. I think the general consensus is that he didn't, and that it was set up before the auction (or a couple years ...
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1answer
46 views

How to wire together 3 power supplies for 3 different pd rails with the same reference 0v

How would I wire together 3 bench power supplies to get potential differences of +12, +24 and -6V, all with respect to the same 0V? All 3 of the bench power supplies have positive, negative and ground ...
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9answers
3k views

In which scenarios is it important to measure microampere?

With the situation of finding a new multimeter, I found myself lost to the number of available devices on the market. For sure, to find the most suitable device I have to set some requirements. While ...
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0answers
69 views

Make a double-tapping button (ideally without ICs or keeping ICs to a minimum) for a small “tiny cell” powered device

Conditions: small device, extremely space constrained (large caps are a no-go) Powered by a small battery (something like under 120 mah) Thus, adding a few more ICs like the 555 or "TimeBlox ...
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1answer
140 views

How to program STM32L011

I tried to program specific STM ultra-low power series (STM32L011D4-tssop14). JLink programmer doesn't support this type of STM32 MCUs. so I tried to program this MCU by STLINK-V2 (SW mode). to do ...
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1answer
78 views

Increased current consumption of micro-power devices

I've been working with microwatt and nanowatt power consumption devices for a while and I've mentioned that sometimes, due to unknown reason, current consumption increases in order of magnitude. ...