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Monitor battery voltage arduino8/19/2023 I'm using a 2000mAh LiPo battery and a LOLIN32 board (ESP32 based), but you can use any microcontroller you'd like, including an Arduino. Here's a simplified schematic that should work regardless of the breakout board you have: Wiring it upĬonnecting this breakout board to your microcontroller is easy: connect the power output to the VIN of your board and connect the SDA and SCL pins for i2c connectivity. Other brands have similar boards: SparkFun / AliExpress. It also has an interrupt pin, so you can have it wake your microcontroller when the battery dips below a certain level.Īnd even more good news: it's available as a breakout board for DIY projects, such as this one from DFRobot: It works through an i2c interface, and it can report the battery's percentage and voltage. It doesn't require resistors or calibration. This tiny chip uses the ModelGauge algorithm to measure a battery's capacity. Fuel Gauge: MAX17043Ī better solution is to use a "battery fuel gauge," such as the Maxim Integrated MAX17043 ( datasheet). It's challenging to convert a measured voltage into a battery percentage. The voltage drops off quickly in the beginning, stays very stable for a long time, and then suddenly drops low at the end of its life: And secondly, the voltage of Li-ion or LiPo batteries doesn't drop linearly. First up: it continuously drains the battery (depending on the resistors you use). Usually with a voltage divider to bring down the voltage so that an ADC can read it.īut this method is not ideal. Show us what you make by tagging on Instagram, Twitter, or Facebook so we can feature it.Many websites tell you to measure the battery level by measuring its voltage. If you have any questions or feedback, feel free to email us or make a post on our forum. Note: The voltage will be accurate to within about 0.1V, but you can calibrate this difference by measuring the voltage at full charge and accounting for that discrepancy. Your screen is probably prettier than mine This is what your program results should look like on the TinyScreen+: You can use this program to do some testing and find out what works for you and your projects that need careful power monitoring. This code does not directly print out the state of charge (%) of the battery because that must be established on a case-by-case basis depending on the hardware you're using and the intensity of your program. Plug your MicroUSB cable into your TinyScreen+, and use the Arduino IDE to upload this program: To get an estimate of the right voltage to be referenced as the "battery is about to die" voltage, you will have to do some testing and use your own discretion based on the current draw of your project.Īll you have to do is insert the battery into the TinyScreen+ and use a MicroUSB cable to connect the TinyScreen+ to your computer, it's that easy.Īll you need is the Arduino IDE and the TinyScreen library, which you should already have if you have completed the TinyScreen+ Setup Tutorial! This can serve as a rough estimate for how much time a program can be sufficiently powered if you know the amount of current your program is drawing.įun Fact: batteries will have a longer lifetime if only 90-95% of their charge is used at a time rather than continuously draining a battery down until it completely dies. If you want to estimate how long a program you're running will last on the battery you have, pay attention to the mAh value on the battery. So while this tutorial reads out the voltage of a battery, the voltage will pretty much stay the same for the life of the battery. Once enough current has been drawn over enough time, the voltage will drop as the battery is dying. You can see that the voltage of a battery over time will pretty much stay the same for most of its life with a gradual decrease. This diagram doesn't exactly match up with our batteries, but it serves as a good discussion piece for lipo batteries. So why can't we get an exact reading and how do we estimate the imminent death of a battery?Ī graph of a battery's rate of discharge at different capacities(C) While it is probably not possible to get an exact reading of the percentage of a battery, you can get a pretty good approximation using the voltage reading of the battery and the time the program has been running. TinyScreen library (You can download this from the Arduino Library Manager, find out how in our Installing Arduino Libraries Tutorial).With this knowledge, you can (very approximately) keep track of how much life your TinyScreen+ project has left. This tutorial will show you how to read out the voltage of your battery using a TinyScreen+. TinyScreen+ Windows 7/8 Driver Installation Large/Small Button & Switch Wireling Python Developing a Game for the Tiny Arcade & Pocket Arcade
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