The battery-operated tag has no wiki summary.
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How to properly turn off a Raspberry Pi when instant plug-out is a criteria [duplicate]
I want to create a stand-alone internet radio device. Therefore I want to use an existing subwoofer box with connected speakers. Inside the subwoofer box there is the electronics for the sound system. ...
3
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2answers
84 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 ...
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3answers
89 views
Estimate current draw for battery replacement
Trying to revive an old electronic keyboard. It is labelled to take 9-12V and I have an appropriate connector, but don't have an idea of how much current to allow for.
It can also be powered by 6 D ...
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1answer
146 views
Rechargable power for arduino
What is the best way to provide rechargable power for an arduino based portable device? So far I've found the following options:
1: Use removable batteries and include an external charger with my ...
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4answers
185 views
Options for getting 3.3v @ 220mA from small batteries
I have a system running at 3.3v requiring 70mA at most times and 220mA at peaks (roughly 20% of the time). I'd like to find a way to power this from coin cell batteries or other small portable source. ...
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1answer
75 views
Spec'ing an always-on alarm/tracker for a car battery
What is the specification of a standard car battery (e.g. of a 2008 Jetta)?
Say, I want to connect an always-on alarm or a tracker to the electrical system of the car.
Is it likely to deplete the ...
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5answers
213 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 ...
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1answer
136 views
Active 433Mhz RF tag battery life question
I am exploring the world of RTLS system and trying to produce one on my own. I chose 433Mhz frequency for its penetration capabilities and I produced a PCB mounting CC430 TI family MCU-transceiver, ...
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3answers
252 views
A separate MCU to cutoff LiPo on low voltage?
I'm designing a project that is going to work on a flying quadcopter. It features an ATmega328P MCU in the main 5V circuit, and is powered by a small (<500 mAh) 1-cell LiPo battery. I want to ...
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1answer
146 views
Battery monitor gauge for embedded development
For one of our upcoming projects, we have a battery pack consisting of 12 Energizer L91(Lithium /Iron disulphide AA Battery).
We divide this battery pack into three sets of 2 ,5 and 5. In order to ...
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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 ...
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2answers
89 views
battery lifetime with self discharge
I want to calculate the lifetime of a battery operated device. Without self discharge of the battery, it is easy to calculate the lifetime, it's just the battery capacity \$Q\$ (given in mAh) divided ...
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0answers
74 views
Making a Plug In or Lead Acid for a Cordless 28v DC Milwaukee Bandsaw [closed]
i have a Milwaukee bandsaw (model # 0729-20) v28 that uses an imperfect Li-Ion battery technology that's pretty well documented to suck. i have four batteries and they all barely hold a charge but ...
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1answer
118 views
LED properties for throwies
A throwie is a small LED attached to a coin battery and a rare earth magnet. In quantity, they are used for creating non-destructive graffiti and light displays. Singly or in small quantities they ...
2
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1answer
160 views
Battery powered sensor node power down circuit
I am using the BQ24079T to control power for a wireless, battery powered sensor node. The MCU will operate in one of two modes: periodic sample mode where it takes sensor readings and then sleeps, or ...
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1answer
143 views
If I turn a AA around will it drain or damage electronics?
I have an Apple Bluetooth keyboard. The thing turns on all the time when I put it in my backpack. This is bad because it blocks the soft keyboard on my phone. It runs on 2 AA batteries. Lately, I ...
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1answer
140 views
Battery powered vending machine. Possible or a pipe dream?
Is it possible to power a vending machine with some form of battery power for a 24 hour period!
Info I have on vending machines:
Most run on 115 V at 10.5 A.
Power usage is estimated at 3.1 - 4.4 ...
6
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1answer
437 views
LiPo vs. NiMH for kid's toy
I've been researching here and on google regarding potential battery technologies for a toy that I want to make for my kids. I was hoping to get others' perspectives on this, keeping in mind that ...
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1answer
188 views
How does range affect Xbee's power consumption?
I am using Xbee ZB SMT in a module, with a microcontroler and sensor, all powered by a battery.
Are there any studies on how range affects the power consumption of the Xbee module?
And as I would very ...
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1answer
238 views
Really loud, yet compact, long(-ish) duration, battery operated — hooter / siren
Is it possible to design a small / compact, hand-held siren (i.e. with a loud hooter), that is battery powered and fits into something like a 3"x3"x2" box ?
The requirements in more detail:
Hooter ...
1
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1answer
90 views
Whitenoise Signal from Microcontroller Amplification IC Advice
I'm looking to hook up a piezoelectric PZT to a microcontroller that will be providing a white noise signal. However, the 5ish volts that the microcontroller can spit out isn't strong enough to ...
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1answer
221 views
6x UV-leds in parallel turning on and off when they should be on all the time
I have 6x UV-leds in parallel driven by a 6V source. The problem I have is that they glow for a little while, then they
are completely off for a little while, then glows and then they are off ...
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5answers
842 views
Coin Cell Battery for Arduino/Microcontroller
Excuse the lack of electrical engineering knowledge but I have an Arduino Uno microcontroller that I want to power with a coin cell battery.
The project will have 6 LED lights that will flash for a ...
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0answers
29 views
Building an AUTOMATIC MUSIC BOX - HELP! [duplicate]
Possible Duplicate:
Automating music box with electric motor
I am a music composer and total noob. So please excuse my lack of engineering knowledge.
I am attempting to build a music box ...
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2answers
145 views
What Components might these Be?
I've been researching on backup power system for embedded devices that must run uninterrupted on mains or backup.
I was trying to study an energy meter board i have with me and came upon a circuit i ...
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1answer
2k views
Why don't my rechargeable AAA batteries work in my cordless phone? [closed]
I'm trying to replace the AAA batteries that came with my BT cordless phone, as they are terrible quality and have quickly degraded (they now only last about 20 minutes after full charge). They are ...
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2answers
376 views
What kind of computer do I use to program an atmega?
What kind of computer (Mac OS X, Ubuntu linux, or Windows) Would I need to compile an program/operating system for an atmega microcontroller? I want the microcontroller to be stand alone at some point ...
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3answers
152 views
How long would this battery device last?
How long could this device be expected to last before needing a new battery?
If that is too subjective, is there some kind of calculation that can be done from the given information (draw, battery ...
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3answers
621 views
Most efficient way to achieve 3.6V or less from NiMH or Li-Ion batteries (when fully charged)
I have a micro and RF module both which I'd like to power from either 3 AA NiMH cells or a single 18650 Li-ion cell. Haven't decided which I'll use yet. My current requirements aren't that much (~2mA ...
1
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1answer
202 views
How to provide stable power to RF receiver when operating on small batteries with blinking LEDs
I have a very simple circuit design (simple to keep cost low) consiting of a super-regenerative (or super-heterodyne) RF receiver, a Microchip PIC and 3 LEDs. These are powered on 3 or 4 AG13 ...
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2answers
123 views
Powering Nerf Gun With Wall Adapter
I have the Nerf Stampede gun that i am planning on making an automated turret from and need some help running it from a wall adapter, so here is where i stand:
The gun normally requires 9V (6 ...
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1answer
376 views
Battery powered light curtain of 100-150 LEDs
I have a hobby project of putting together a light curtain of 100-150 LEDs (3V, 20mA). It is meant to be used in an event outdoors without mains power. It could be operated with bunch of ordinary ...
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1answer
44 views
Do I need the battery to be present if notebook connected via Car Universal Laptop Power Adapter? [closed]
I am going for holiday and I want to use my old old Acer. The battery lasts for about 10 mins if not connected to the electricity outlet.
If the notebook is connected via Car Universal Laptop Power ...
3
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1answer
567 views
Automating music box with electric motor
I recently purchased a DIY music box kit from a website which I will not link to here. If you watch this video you can see that it has a serious design flaw: it has a tiny hand-crank, and it's thus ...
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2answers
178 views
Accepting a Range of Input Voltage that Straddles Operating Voltage
I want to design a system that runs at 5V and about 350mA. I want that system to accept an input voltage between 1.8V and 15V. How can I achieve that goal with a minimum component cost in my input ...
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1answer
316 views
Sensing a USB device plugged in without having to supply 5 volt power all the time
I am designing a device using the PIC32MX795 processor that will act as a USB host. Since it is a battery operating device, I would prefer to not supply 5 volts all of the time on the USB port (the ...
