Tag Archives: CR2032

ATtiny85 Game Console


webboggles.com has designed a SSD1306 OLED Screen based game kit using an ATtiny85 microcontroller. They also sell it as a kit to assemble it yourself.

The new snap case has been updated to allow enough height for the screen header as well as a factory made CR2032 battery holder.
The buttons have been concealed to prevent spontaneous button presses inside bags and pockets.

ATtiny85 Game Console – [Link]



by Rusivan @ instructables.com:

In this article I will try to tell you about the gift I made for my girlfriend!

The basis of the scheme is a microcontroller Atmega8, 1K resistor, selected in such a way as not to overload the microcontroller ports. SMD resistors and diodes, size 1206.

On the reverse side of the board, there are two batteries CR2032, two capacitors, voltage regulator LM7805, and the power button with latching.

DIY SMD LED heart – [Link]

How Much Energy Can You Get From A Coin Cell?


Embedded legend Jack Ganssle tackles the question of how much juice you can pull from a coin cell. He writes:

About a year ago I wrote of my on-going experiments to determine how coin cells behave. This was motivated by what I consider outrageous claims made by a number of MCU vendors that their processors can run for several decades from a single CR2032 cell. Some vendors take their MCU’s sleep currents and divide those into the battery’s 225 mAh capacity to get these figures. Of course, no battery vendor I’ve found specifies a shelf life longer than a decade (at least one was unable to define “shelf life

Datalogger in an Altoids can


karllunt @ www.seanet.com writes:

This is pretty much one of those required projects; everyone builds a datalogger in an Altoids can. But each is different and I enjoyed making mine.

Uses ATmega328P (low power, 32K flash for lots of program space)
Uses Maxim/Dallas DS1337 Real Time Clock (uses I2C)
Logs data to microSD flash card, readable on PC (uses FAT32)
Runs on two AAA alkaline batteries
Low power draw (exact consumption varies based on SD card used)
Supports RS-232 for entering commands
Uses CR2032 lithium coin cell for RTC backup
Uses Analog Devices TMP36 for temperature sensor (not shown, it gets wired to the green four-position terminal shown below)
Uses SparkFun 3.3VDC boost converter to provide stable voltage even as batteries die

Datalogger in an Altoids can – [Link]

Simple capacitance meter bins parts


This Design Idea describes a simple two-chip CMOS circuit that can sort capacitors into 20 bins over a wide range (100pF to 1μF), using 10 LEDs to display the value range. The circuit is power efficient and can be run using two CR2032 cells. As such, it can be built into a handheld probe. by Raju Baddi

Simple capacitance meter bins parts – [Link]

Understanding Coin Cell Limitations

Planning on powering that next über-low-power board of yours from a measly CR2032 coin cell?  Read this app note to understand exactly what the limitations of coin cells are: [via]

When designing a small wireless sensor node to be powered by the popular CR2032 coin cell, some sources claim there is a 15mA “limit

Digital clock with backup battery

Sergei Bezrukov writes:

A digital clock with a LED display should be designed for being powered from a wall power supply, as the display draws a lot of current. However, such clock needs a reset after every power outage if no backup battery is provided. Usually commercial clocks use a 9V backup battery. Such batteries take a lot of space and are relatively expensive. If the clock electronics works from 3-5V, a lot of battery energy is dissipating for nothing.

This clock uses a cheaper and much smaller CR2032 battery as a backup. It is based on a Texas Instruments MSP430F2101 16-bit microcontroller, which can be purchased just for $1.50. If the display is off, the microcontroller itself draws about 14 μA in average due to being kept in sleep mode for most of the time. The input voltage in the range 5 – 15V is converted into a 3.6V by a linear voltage regulator MIC5209-3.6. The average current drawn from an external power supply is about 35 mA, depending on the digits shown on the display.

Digital clock with backup battery – [Link]

The impact of high pulse drain on CR2032 coin-cell battery capacity

If you design circuits powered by CR2032 batteries here’s an article located by Joe Desbonnet which you should consider: [via]

This is an interesting article on how the performance of a cell/battery under pulsed loads can vary dramatically depending on period, peak current, duty cycle and other factors. The article discusses the performance of a CR2032 button cell driving low power wireless protocols such as ANT+ and Bluetooth v4.0.

The impact of high pulse drain on CR2032 coin-cell battery capacity – [Link]

Mini sound annoyer

This “Annoyer” basically emits a high pitched “beep” randomly every 2-15 minutes. The beep is very high pitched so it is impossible to find where this beep is coming from. No matter where you walk around the room, because of the pitch of the beep, you cannot tell if you are closer, farther, or even what direction it is coming from. The beep is just loud enough to annoy anyone near it -just ask my wife 🙂 It runs off of a 3v cr2032 coin cell battery. I don’t know exactly how long the battery will last, but mine has been going for 2.5 months in my co-worker’s office and is still going strong (yes, I am evil :0) The Annoyer is based on a Pic10f202 microcontroller. This is a very cheap uController (about $.50). This project has very few parts as most of the work is done in software.

Mini sound annoyer – [Link]