by Jim @ jimlaurwilliams.org:
I got a couple of cheap ($1.29) 1A USB LiPo chargers since I’m doing more and more LiPo/LiIon powered stuff. I mostly discharged a recycled 18650 cell for a test load and it looks like it does charge at nearly 1A. Two LEDs – red charging, green (mine is blue) fully charged. Seems like a pretty ideal cheap device.
Cheap USB LiPo charger notes - [Link]
Josh Levine writes:
It can be nice to know how much battery power you have. It becomes critically important with LiPo batteries since you can permanently damage them by running the voltage down too low. Typically battery voltage detection requires adding a circuit with extra parts and their associated power requirements. Wouldn’t it be great to be able to do this using nothing but software? Read on for a no parts, no pins, no power solution…
Battery fuel gauge with zero parts and zero pins on AVR - [Link]
When you think Raspberry Pi and camera you probably already know the score; a small camera board that plugs into the Pi’s CSI connector fitted with a fixed-focus wide-angle lens. This versatile setup has been the basis of all sorts of homebrew applications. The SnapPiCam takes the Pi down a different route and converts it into a 5 MP digital camera with interchangeable lens.
Gregory L Holloway is the brains behind this idea, he developed it as an entry into an Instructables competition (which he won) and the response he got encouraged him to launch it on Kickstarter. The design uses the lower spec RPi A without an Ethernet port and with 256 MB of RAM. The camera includes a LiPo battery and DC-DC converter to make it truly portable and different versions allow you to add a rear touchscreen and various interchangeable, magnetic-mount lens ranging from wide-angle to telephoto zoom.
SnapPiCam, a DIY Digital Camera - [Link]
Perhaps the most frequently used rechargeable batteries on the market nowadays – Lithium-Polymer (Li-Po) can be found also in our offer.
From the beginning of electronics, the world searches for an “ideal” rechargeable battery. So far such a battery doesn´t exist (maybe supercapacitors in the future), but Li-Po (Li-Pol) cells are quite near to an ideal in some aspects.
Very low self-discharge (approx. 5% / month), high voltage of a cell (3,7-3,8V average), high energy density and a low weight, considerably stable discharge voltage and a possibility to recharge anytime are one of the main advantages of Li-Po cells. Another benefits are advantageous flat shape, high variability in dimensions and a long lifetime. No wonder, that Li-Po cells have become no. 1 in consumer electronics, hand tools and in many industrial devices.
Perhaps the only drawback of these cells is their lower chemical stability at overcharging (in a corner case ending up with a fire). But that´s the case which is practically eliminated at a common operation with a suitable charging circuit (chip or a charger intended for Li-Po).
Basic principle at usage is not to exceed approx. 4.25V charging voltage and the battery is almost discharged at a voltage below approx. 3.0V (2.75V). On the very end of a discharge cycle, the inner resistance slightly increases, what can cause a slight heating of a battery at higher currents – it is a normal behavior. Charging is usually based on a method constant voltage/ limited current. In principle it´s possible to use the same chargers and charging circuits for Li-Ion as well as Li-Po cells.
At a usual usage and discharging to say 20-80%, Li-Po cells will reward you by a reliable operation and a long lifetime. Flat shape is ideal for various handheld equipment, as well for usage in flat enclosures. In respect to a low self-discharge it´s possible to use Li-Po cells even as a backup energy source.
In our offer can be found several several Li-Po types from company EEMB with a capacity of 130 mAh to 2000 mAh. Exact list of available types and datasheets can be found below this article. Upon request, we´re able to provide you also many other types.
Try the most favorite type of batteries - [Link]
Jianan Li made this LiPo Booster project, that is available at Github:
LiPo Booster is a breadboard-friendly boost converter board based on the TPS61230 IC from Texus Instrument. It has an output voltage of 5V, and is designed to be used with a single cell LiPo battery.
LiPo Booster, a breadboard-friendly boost converter board based on TPS61230 - [Link]
LiPo Booster –
LiPo Booster is a breadboard-friendly boost converter board based on the TPS61230 IC from Texas Instrument. It has an output voltage of 5V, and is designed to be used with a single cell LiPo battery.
For normal and half size breadboards, the LiPo Booster can be plugged into the power rails without blocking the vertical 5-pin strips. It can also be used with a tiny breadboard or breadboard of any sizes as shown below.
LiPo Booster - [Link]
This page is related to the yamppPod (yPod) MP3 player project of Jesper Hansen at www.yampp.com The hardware of this player is based around an Atmel ARM7, here AT90SAM7S128 and the VLSI VS1033 MPEG3 codec. Powered by a single LiIo/LiPo battery, the player also includes a color LCD, a 5-way switch for user inputs and a TWI EEPROM to store settings. A Micro SD card slot provides access to the music and system files stored a simple Micro SD card. Recharging the battery as well as data exchange with a PC is done by the USB interface available via mini-USB connector. A 3.5mm stereo jack provides the audio signal for headphones or any kind of amplifier. And everything located on a tiny 4-layer PCB.
yamppPod MP3 Player - [Link]
Xose Perez of Tinkerman has written an article detailing the build of his weather station:
Arduino FIO based weather station with a DHT22 temperature & humidity sensor and a BMP085 barometric pressure sensor. The whole sensor will be powered by a solar panel (doubling as irradiance sensor) and backed by a LiPo cell.
Weather station - [Link]
Digital pins 0-7, Analog 2-5, and a RST, V+, and GND pin are broken out to two rows of pins, maintaining about half the pins in a familiar shape and organization. A JST connector for LiPo batteries like the ones available through SparkFun and Adafruit and an MCP73811/2 charger circuit makes the Demiduino well suited for portable applications. On the back, I’ve also included CR1225 clips for ~3v3 power from easy to find coin cell batteries, and a power switch to save battery life.
Demiduino, another tiny Arduino compatible board - [Link]
Paul Asselin has written a description of his design of a USB Lithium Polymer battery charger – [via]
I wanted to build a cheap USB LiPo charger and didn’t like the unavailability nor the price of the Maxim’s MAX1555. Searching for something better, I stumbled upon the Microchip MCP73831. It is still way too expensive in single quantities but there ain’t too many options.
The board is intentionally small and has a status LED. There really isn’t much more to it, it’s a single purpose device and just does the job. It is proudly Open Source Hardware.