Involving or pertaining to a circuit or device that is intended to be operated with cells or batteries (as opposed to mains power, for example).

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1answer
33 views

Led head light - preventing Battery contacts from rusting

I have a cheapo Asda headlight who'sbattery contacts keep rusting over. Even if you leave the bloody thing indoors it rusts after awhile. Is there any chemicals I can put on it to stop this from ...
0
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1answer
94 views

Decoupling a power supply

I'm building my first biped robot, using a Raspberry Pi as the brain. My problem is, I want to decouple the battery before I use it to power the Pi. The reason I want to decouple the battery is ...
0
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1answer
41 views

Solar Charge Battery Low Voltage Disconnecting

I have a 4.2V 120mA max solar panel and 3.7V 1200mAh battery. I'm trying to make a solar power system for my arduino. I search through battery management IC's and generally understand the charge ...
0
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1answer
72 views

24 Hr A Day Powered Aquatic Pump

I am looking to install a DC 12V 6W submersible aquatic pool pump for use in a small scale hydroponic setup. The location of the beds will be too far away from mains electrical, and I would like to ...
1
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1answer
56 views

Power Arduino Mini with 3 AA batteries

The arduino mini consumes 5V. The Voltage input is min. 7V. Is it possible to ignore that and attach 3 AA batteries (4.5V) or 4AA Batteries 6V between the GND and 5V pin of an arduino mini for long ...
0
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1answer
58 views

Wireless “Arduino” sensors - what is at least needed on circuit?

When I finished my Master Unit for Home Control, I want to attach some Wireless sensors via 433MHz Protocol. (At least 2 ones, 1 for Measuring the outdoor Temperature/Humidity with an DHT22 and ...
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0answers
41 views

Designing battery circuit for a custom tablet

I am designing a tablet with SOC computer. I am trying to figure out how the battery will interface with this. I know that I will need to use some Charging IC that can supply constant current and ...
1
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3answers
78 views

2xAAA battery => 3.3v/250mA step-up converter with logic-driven power control [superseded]

EDIT: The requirements in the question below appear to be practically unsolvable, but happily after a bit of digging I actually found an alternative equivalent RS232 device which runs off a 3.7V Li-Po ...
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3answers
186 views

Smallest, simplest possible (randomly) flashing 2-3 LED circuit

I am trying to randomly flash 2-3 LEDs using the smallest possible circuit using 1 or 2 CR2032 batteries. Can I power 2-3 3mm (3-3.4v, 20mA)(amber, white) flashing (slow 1Hz) LEDs using one CR2032 ...
1
vote
1answer
118 views

Switching Arduino/ATMega to sleep mode when on battery

I'm trying to make a small clock but want to ditch the need for a separate RTC chip with battery backup. What I would like to do, instead, is keep track of the time completely on the ATMega using the ...
4
votes
1answer
195 views

How good is the advice to run the car headlights before starting the car in cold weather?

I'll do my best to formulate this as a purely electrical problem so that it isn't claimed to be belonging to Vehicle Maintenance SE. We have a lead-acid starter battery (not a deep cycle fashion) ...
0
votes
1answer
265 views

switch between battery and usb power no microcontroller circuit

Following an earlier question about how to switch between battery and USB power, I would love to implement the TC2014 LDO as suggested by Russell McMahon. That way I could switch between 4AA ...
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1answer
88 views

Modding a charger into a power supply + charger?

I am making a handheld radio telescope which needs 13-18v to power and currently runs off 2 9V batteries. However it eats power like mad, drains them so hard that it actually needs to be recalibrated ...
0
votes
2answers
104 views

Convert Plugin Christmas decoration to a battery operated light

I have an old ceramic Christmas tree that I would like to convert to a battery powered source in order to get rid of the cord. Ideally I'd love to add a timer to it as well. I'm not sure what ...
1
vote
1answer
58 views

Power rail design from Li-Polymer battery chip output

Case: I am building a battery driven device and so far it seems like I will be using the MCP73871 to provide my device with battery power and charging via USB. I need to regulate the output from the ...
2
votes
2answers
575 views

Arduino: How can one control a 2-wire DC motor with PWM?

I want to control the speed of a two-wire DC motor using PWM. I already managed to control a 4-wire motor, but now I need to use a two-wire motor. I would connect it to the Arduino directly, but the ...
2
votes
3answers
223 views

Best way to reduce battery consumption for LED device?

I'm building a device that needs to "light up" to indicate status to the user. I of course want to use LEDs to light the device up, but I'm worried about battery consumption since I would like it to ...
3
votes
1answer
333 views

Battery powered device hardware design tips

I'm working on a prototype product(Wifi motion sensor) that will be powered from a battery source, it has a mega328(arduino bootloader, with sleep mode on and wake on interrupt,and WDT in case it ...
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votes
1answer
235 views

How to hack a battery powered device to use 1 Li-ion cell instead of 2 NiMH cells?

I want to hack a cordless computer mouse, so it can be used with 1 lithium ion cell (standard cobalt cathode to be extra precise) instead of the intended 2 nickel metal hydride cells. The main reason ...
1
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1answer
149 views

How to measure battery charge and depletion over time

When using my various electronic devices, they always seem to know how much charge is left in the battery. They also know when the battery is completely charged. Not exactly sure how this is ...
4
votes
1answer
68 views

Battery voltage regulation

I am designing a simple device that incorporates an LCD display that requires a 3V operating voltage, but I can only use a single 1.5V battery in my design. How can battery voltage be regulated ...
-2
votes
1answer
148 views

What battery is lightweight and has a lot of power?

I'm creating an Arduino project, for that project I'm looking for batteries like the ones used to power scooters or electric wheelchairs, so powerful that they can carry the weight of a human and last ...
1
vote
2answers
119 views

Best value Lithium ion/polymer cells/batteries

I've built a sound reactive, android controlled, wearable RGB LED matrix/suit which I'm currently powering with a rather heavy 12V 3Ah SLA battery. I'm looking to switch to lithium or ni-mh packs and ...
0
votes
2answers
190 views

Calculating the resistor needed to replace batteries with another power supply

The project I'm working on is going to use a LiPo Battery to run a Raspberry Pi, Arduino, and some LED's. I currently have all of that working. One final thing I want to do is have a "Speaker" plugged ...
1
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0answers
87 views

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
votes
2answers
177 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
108 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 ...
6
votes
1answer
2k 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 ...
1
vote
1answer
112 views

Power analysis of a simple circuit and battery lifetimes

I only do electronics stuff as a hobby so forgive my simple question. I have a simple IR LED/photodiode detector circuit hooked up to an arduino microcontroller. It's not important but the purpose is ...
0
votes
4answers
913 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. ...
1
vote
1answer
99 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 ...
4
votes
5answers
367 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
2answers
290 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, ...
6
votes
3answers
446 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 ...
0
votes
1answer
201 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 ...
6
votes
5answers
3k 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 ...
3
votes
2answers
129 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 ...
0
votes
1answer
149 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 ...
4
votes
1answer
284 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 ...
6
votes
1answer
165 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 ...
2
votes
1answer
213 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 ...
8
votes
2answers
734 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 ...
1
vote
1answer
331 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 ...
0
votes
1answer
303 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
vote
1answer
127 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 ...
6
votes
1answer
278 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 ...
5
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5answers
2k 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 ...
0
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2answers
172 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 ...
0
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1answer
3k 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 ...
0
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2answers
434 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 ...