The increased interest in IoT and electric automobiles around the world is driving an increase in the use of Lithium-Ion/Lithium-Polymer/NiCd/NiMH batteries as more devices and applications are using them, due to their high energy storage capacity to size ratio. This increased interest is, however, causing an increase in the number of batteries with “fake” ampere-hours ratings in the market. These fake ratings could lead to the failure of several projects, especially IoT projects in which developers factor in the Battery ratings in their On-time calculations. As such, to find a way of mitigating the failure-risks this problem poses, for today’s tutorial, we are going to build a battery capacity tester which can be used to get the correct energy storage capacity of any Lithium-Ion/Lithium-Polymer/NiCd/NiMH batteries (with voltage below <5v).
Battery (Lithium, NiMH, NiCd) Capacity Tester Using Arduino – [Link]
The increased interest in IoT and electric automobiles around the world is driving an increase in the use of Lithium-Ion/Lithium-Polymer/NiCd/NiMH batteries as more devices and applications are using them, due to their high energy storage capacity to size ratio. This increased interest is, however, causing an increase in the number of batteries with “fake” ampere-hours ratings in the market. These fake ratings could lead to the failure of several projects, especially IoT projects in which developers factor in the Battery ratings in their On-time calculations. As such, to find a way of mitigating the failure-risks this problem poses, for today’s tutorial, we are going to build a battery capacity tester which can be used to get the correct energy storage capacity of any Lithium-Ion/Lithium-Polymer/NiCd/NiMH batteries (with voltage below <5v).
Demo SPlash Screen
There are quite a number of battery testing projects on the internet, each with a different approach, but for today’s tutorial we will be chronicling the efforts of Instructables user: Sam Moshiri, due to the quality of his build and its standalone and compact nature. The goal of the project according to him was to build a compact, easy-to-build device, capable of measuring the capacity of almost any kind of battery (< 5V) using an adjustable constant load setup with an LCD on which the capacity of the battery is displayed.
The idea behind the constant load current setup is simple. If you draw a constant current from a battery over a particular period of time, you will be able to calculate the true ampere-hour capacity of the battery based on the amount of voltage that was dropped during that time. To achieve the constant load current, a resistor network with an LM358 operation amplifier and a MOSFET was used. The setup has two push buttons (+ and -) that allow users to set the load current before the process starts, and a third push-button to reset the board when it’s time to test another battery. The Battery’s voltage is fed into one of the analog pins on an Arduino Nano which monitors the voltage drop based on the preset current draw, calculates the battery capacity, and displays it on a 16×2 LCD Display.
At the end of this tutorial, you would know not only how to determine the battery capacity, but also how to design for constant load / constant current draw and use a 16×2 LCD display with the Arduino.
Ready? Let’s dive in!
Required Components
The components required for this project are provided below:
Arduino Nano
16 x 2 LCD Display
LM358N
Resistors – 4.7k(2), 47R(2), 1M, 10k, 3R
Capacitors 100nF(6), 100uf-16V, 1000uF-16V
Tact Switch (3)
IRF3710
Jumper Wires
Battery Holder
Variable Power Supply
Although the project was implemented on a PCB to make it compact, all of the components used are of DIP type to make it easy to solder for everyone, irrespective of the level of their soldering skills. The Arduino Nano was used because it can be easily soldered on a PCB, asides this reason, any other board could have been used.
Schematics
As earlier mentioned, the project was implemented using a PCB to make it portable. The PCB was designed using Altium and all the files are attached under the download section of the tutorial. The components are connected as shown in the schematics below;
A comprehensive BOM showing how each component fits into the schematics above is shown in the table below:
To create the PCB, Sam used the SamacSys component libraries, because of features like the industrial IPC standards which they follow and the fact that they are free. The Libraries were installed using the Altium Library plugin. The PCB after development is shown in the image below along with the assembled version of the board.
assembled PCB
Code
The code for this project is quite straightforward. We will basically monitor the time it takes for a battery to get to a predefined “low” value, and calculate the battery’s capacity using the depletion rate and the preset constant load current that was drawn from it. The whole process is displayed on an LCD in an interactive manner.
To reduce the amount of code to be written, we will use the Arduino Liquid Crystal library along with the JCbutton library. The liquid crystal library which comes preinstalled on the Arduino will be used to interact with the 16×2 LCD, while the JCbutton library, which can be downloaded from the attached link, is used in processing the state of the tact buttons, determining when it has been pressed, long pressed, etc., while also handling things like debounce.
As usual, I will do a quick explanation of how the code works with a focus on sections that I feel might be difficult to follow.
The code starts by importing the two libraries that will be used.
#include <LiquidCrystal.h>
#include <JC_Button.h>
Next, we create a variable to hold the minimum level to which the battery is allowed to drop, and several other variables to store different values. The Current array is a series of value which is matched to the rotation of the R7 potentiometer which determines the load current.
After initializing the LCD, display a splash screen of some sort with the name of the project and the version. After 3s, the display is cleared and it displays the Load Adj: up/Down button showing it is waiting for the user to set a load current.
Each time the Up button is pressed, it adds 5 to the Pwm_Value variable which is used as the load current indicator. The inverse is true for the Down button. For each of the button pressed, the user is provided with visual feedback of the increase or decrease in the PWM_value, on the Display.
If the Up button is long pressed (indicated by 1000ms), the system switches mode as it assumes the user has selected a load current that satisfies them. The mode switch involves invoking the timer interrupt() function which handles all the calculations involved with determining the capacity of the battery. This cycle is repeated as the loop continues.
The timerInterrupt() function handles most of the project’s heavy lifting. It continuously monitors the battery voltage and as long as it’s not yet at the preset Low_BAT_Level, it increments the time. As soon as the measured battery voltage becomes less than the Low_BAT_Level, it stops the time increment and uses it to estimate the capacity of the battery. At this point, the buzzer is turned on and off in a pattern to indicate the completion of the process.
With the code completed and your PCB ready, connect the Arduino Nano to your computer and upload the code to it. After the code upload, you should see the LCD come up with the splash screen as shown in the image below.
Demo Splash Screen
With the code uploaded, we then need to power the board via an external power supply and connect a battery to it as shown in the image below. Based on this current design, you should only power the board with a maximum of 9V.
With the power supply and battery connected, set your desired load Current using the up and down buttons then press and hold the up button till you hear the buzzer beeps, to kick start the process.
Set the desired Load Current
As the process proceeds, an update will be provided on the screen, showing the time that has elapsed and the voltage of the battery.
Capacity Determination in Progress
At the end of the process, the battery’s true capacity is displayed as shown in the image below.
Battery Capacity.
That’s it. For the demo, a battery rated 8800mAh was used but at the end of the test, the battery was discovered to only have an energy capacity of 1190mAh.
That’s it for this tutorial guy’s thanks for reading. As usual, you can reach out to me via the comment section if you have any questions or difficulties replicating the project.
Within a period of 10 years at the end of the 19th century, many technological achievements allowed to extend the use of alternating current and overcome the limitations of direct current for the distribution of electricity to the public.
In 1882, the transformer is invented in France which eases the distribution of the alternating current as we will mention in the first section. Only six years later, Tesla created the first prototype of the synchronous machine which as we detail in the main core of this tutorial, generates a particular form of alternating current from a primary form of energy.
This particular alternating current can be described by a mathematical function and is commonly known as a sine or sinusoidal waveform. In this tutorial, we will refer to several previous articles to regroup information and give more details about the sinusoidal waveform.
First of all, a short presentation will define the important parameters of a sine function and why it is so important in electronics.
In a second section, we investigate their generation process with alternators which includes an understanding of electromagnetic phenomena. We focus on the architecture of the rotor and stator which are the two most important parts involved in electricity generation.
Presentation
Sine waveforms are found in many domains of maths and physics and they can be mechanical or electrical for example. They describe a periodic and smooth oscillation of a certain parameter (current, voltage, movement …etc).
The electrical sine waveform is described mathematically by the sine function y(t) and the general formula is given below :
eq 1 : Sine function expression
The parameter A is the amplitude which unit is in Amps (A) or Volts (V), f is the frequency of oscillation in Hertz (Hz) or the angular velocity ω in radians/second (rad/s) and Φ is the instant phase of the signal in degrees (°) or radians (rad). The oscillation speed can also be given by the period T=1/f which represents the time duration of a cycle.
We also remind the reader that Equation 1 can be transformed into its complex equivalent for simplification and compaction purposes, such as detailed in the tutorial about Complex Numbers.
The conversion between radians to degrees can easily be done knowing that 2π rad=360°. Moreover, the frequency and angular velocity are linked by the identity ω=2πf.
An illustration of these parameters is given in Figure1 that compares two different sine functions.
fig 1 : Illustration of sine functions
In order to know if the phase is different from zero, we can look at the variation of the sine around the origin of time. A sine wave with no instant phase should have an amplitude of 0 at t=0 and increase right after, which is the case of the blue sine function y2(t).
Before talking about the production of such signals, it is worth mentioning why they are so interesting and why they are used in so many applications.
First of all, as we will see in the next section, sine signals can be naturally produced with generators in power plants. Moreover, as already detailed in the AC Waveform tutorial, they are the building blocks of any other period signals such as squares, ramps … Finally, the entire distribution network is based on the use of sine power waveform because their current and voltage amplitudes can easily be adjusted to specific needs with the help of transformers, the transmission power losses are as well decreased.
Generation
The reader is encouraged to refer to our previous articles about AC Waveform and AC Inductance in order to get a preview of what this section will detail in the following.
The generation of an electrical sine signal is done by a synchronous electric motor also known as alternator. The goal of such a device is to transform mechanical energy (rotation) into electricity.
The following Figure 2 presents the schematic architecture and the functioning of a single pole-pair alternator :
fig 2 : Illustration of the functioning of an alternator
The alternator consists of two parts : a stator and a rotor. As the name refers to, the stator is a stationary coil in which the AC electricity is induced and harvested. The rotor is a rotational magnet that generates a magnetic field inside the stator.
The rotation of the rotor is maintained by a primary form of energy : combustion of coal or nuclear material, wind, movement of water in a dam etc … It can be a permanent magnet in which the magnetic field is constant or an electromagnet in which the magnetic field can be tuned depending on the electricity supplied to it. Often, the second option is chosen because a variable amplitude of the magnetic field allow to change the amplitude of the output electrical signal.
The stator is where the induced electric signal is generated thanks to the induction phenomenon. The electric signal produced is naturally a sine waveform because of the circular symmetry of the configuration.
Indeed, according to the induction law, the electric signal e (either the current or voltage) is proportional to the variation of the magnetic flux ΦB within the stator: e=-dΦB /dt. If AS states for the area of the stator coil, we can define a surface vector given by AS=AS.n with n being the unit normal vector to the same surface as shown in Figure 3 :
fig 3 : Illustration of the surface vector of the stator coil and magnetic field
The magnetic flux is simply given by a vectorial product of the field B and the area vector of the stator coil AS :
eq 2 : Expression of the magnetic flux
If we set the angle θ to be at 0° when the axis of the rotor and stator are aligned, we can understand that ΦB=Φmax×cosθ with Φmax=B×AS, the variations of the flux is, therefore, also a sine waveform since the derivative of a cosine is a sine and the angle θ is a function of time. Finally, we can say that the electric output will be as well a sine waveform.
Rotor pole-pairs
An important relation between the frequency of the electric sine output (f) can be given and the rotation speed of the rotor (in RPM) : RPM=60×f. In order to obtain a 50 Hz signal, which is the distribution norm in Europe, the rotor must rotate at 3000 RPM. This high speed can be achieved in a nuclear power plant but in dams, for example, the rotation is much slower.
To maintain a frequency of 50 Hz, a solution consists of increasing the number of pairs of poles of the rotor such as illustrated in Figure 4. With this configuration, a faster variation of the magnetic flux is achieved for the same rotation speed.
fig 4 : Illustration of a double pole-pair alternator
For this example, a 50 Hz output can be observed with a rotation speed of 1500 RPM instead of 3000 RPM. In the general case, if P states the number of pole-pairs, the relation between the rotation speed and output frequency is given by the Equation 3 :
eq 3 : Expression of the rotation speed as a function of frequency and rotor pole-pairs
Stator pole-pairs
In the previous illustrations, the stator consists of only 1 pair of the pole which gives a single-phase current. For high-power applications, however, such as high-voltage distribution, a 3-phase current is more suited since it presents fewer power losses and a more constant average power.
The architecture of such a stator is presented in the Figure 5 below :
fig 5 : Illustration of a 3 pair-pole stator with a single pair-pole rotor
Each phase is separated 120° from the rotation center of the rotor and one pole of each phase in grounded. The total output is, therefore, a combination of 3 sine waves phase-shifted 120° such as presented in the Figure 6 :
fig 6 : Total output of a 3-phase alternator
Most of the modern alternators consist of a 3 pole-pair stator which allows the production of 3-phase sine waves and provides better efficiency. Moreover, a multi pair-pole rotor can be combined in this configuration in order to obtain the required frequency even if the mechanical rotation is slower than 3000 RPM.
Conclusion
Sine waveform plays a major role in many physics domains and especially in electronics since they are present in our daily life, supplying households for more than a century, worldwide.
In the first section of this tutorial, we mathematically described what a sine wave consists thanks to the sine function and explained the amplitude, frequency and phase parameters. We also briefly explain the importance of such signals.
The main core of this article refers to the production of sine signals through the use of alternators. They consist of a rotational part (the rotor) that creates a variable magnetic field in a static coil (the stator) surrounding it. According to the electromagnetic law of induction, an electric sine wave is produced in the stator.
We have pinpointed that the number of pole-pairs of both the stator and rotor can be modified in order to maintain a 50 Hz output with a slower rotation of the rotor or to achieve a 3-phase signal for high-power applications.
Strange Parts visiting a giant factory in China that makes lipo iPhone batteries, aka lithium polymer batteries, and seeing how they are made from start to finish. This is by FAR the coolest and biggest factory I’ve been to date.
Inside an iPhone Battery Factory – in China – [Link]
Advantech VEGA-320 m.2 Edge AI Module is an ultra-compact and low power consumption module with one onboard Intel® Movidius™ Myriad™ X VPU. This module is scalable for multiple video streams edge inference. The VEGA-320 module includes a built-in Edge AI suite. This Edge AI suite features OpenVINO™ toolkit, pre-trained modules, deployment wizard, and third party AI SDK. The VEGA-320 module supports Windows 10 Enterprise, Ubuntu 16.04.3 LTS, and CentOS 7.4. This module operates at 0°C to 45°C temperature range. The VEGA-320 also features passive cooling and hardware acceleration for common deep neural networks. This module is ideal for use in facial detection, pedestrian tracking, human pose estimation, vehicle detection, and optical inspection.
Features
Built-in Edge AI Suite:
OpenVINO™ toolkit
Pre-trained models
Deployment wizard
3rd party AI SDK
TensorFlow and Caffe framework support
Intel® Movidius™ Myriad™ X VPU onboard
Ultra-compact and low power consumption
Hardware acceleration for common deep neural networks
Scalable for multiple video streams edge inference
Take a look at Seeeduino XIAO. What a small size and cute looking! It is the smallest member of the Seeeduino family. Seeeduino XIAO still carries the powerful CPU-ARM® Cortex®-M0+(SAMD21G18) which is a low-power Arduino microcontroller. On the other hand, this little board has good performance in processing but needs less power. As a matter of fact, it is designed in a tiny size and can be used for Arduino wearable devices and small projects.
Apart from the strong CPU, Seeeduino XIAO is excellent in many other functions. It has 14 GPIO PINs, which can be used for 11 analog PINs, 11 digital PINs, 1 I2C interface, 1 UART interface, and 1 SPI interface. Some PINs have various functions, A1/D1 to A10/D10 Pins have PWM functions and Pin A0/D0 has a function of DAC which means you can get true analog signals not PWM signals when you define it as an analog pin, that’s why 14 GPIO PINs can realize more I/O PINs and interfaces. Moreover, Seeeduino XIAO supports the USB Type-C interface which can supply power and download code. There are power pads at the back of the XIAO which support battery and make it designed for wearable devices to become realistic. Except for the power LED, we add a user LED on board for your better coding experience. Usually a Dev. Board as small as this size will use the chip’s inner crystal oscillator for time fixing, in order to make the clock more accurate, Seeeduino XIAO layouts an extra 32.768KHz to make the clock more stable.
Seeeduino XIAO is perfectly compatible with Arduino IDE, you can easily develop some small projects with the help of the large and comprehensive Arduino library. So get one and you will soon love it!
The STM32Fo30 is one of the most popular microcontrollers in the STM32 family. It’s relative low-power specification and high-resolution ADCs fetched it good followership among designers, as such, it was quite interesting to hear that Czechia-based electronics specialist and Tindie user, NiceThings, announced the launch of a new development board based on it, called the PINKY32.
The board was designed with the desire to make all the amazing features of the STM32F030, available to makers in an easy to use a form like the Arduino boards. According to NiceThings, the board was initially designed for a project that required slow dimming of more than one minute which couldn’t be achieved using the Arduino because its PWM is 8bit, forcing him to use the STM32F030 which has a resolution of 16bits.
The board comes with all the powerful features of the STM32F030 with 16kB Flash,4kB SRAM, and hardware I2C and SPI buses for communication with sensors and actuators based on them. It was designed with a low quiescent current LDO on board, which ensures the board only draws few uA in shutdown deep sleep, making it a good option for battery-powered (IoT) projects. According to NiceThings, the Onboard LDO will, however, perform best when the input voltage is 5V but you can feed up to 12V on VIN.
Pinky32 Back view
Staying true to the “ease of use” goals for the boards, Pinky32 comes with a MicroUSB connector and an onboard CH340 serial-to-USB chip through which it supports flashing/debugging by the Arduino IDE over USB. The board uses the same STM32duino Arduino core which enables the programming of boards like; STM32 Bluepill, with the Arduino IDE.
The board is currently available on NiceThings Tindie page for $7 with 64 orders and lots of good reviews so far, but should you want to make your own version of it, NiceThings made the design openly available and all the files can be found on the project’s GitHub page.
More information on the board, it’s price and shipping possibilities can be found on its Tindie Product Page.
As projectors grow more and more popular in home entertainment systems, so have the expectations of users. In addition to ever-higher resolutions, the focus is also on richer colors, contrasts and, of course, higher brightness. With the Ostar Projection Power family, Osram has succeeded for the first time in achieving projector brightness levels beyond the 3,000 ANSI lumen barrier using LEDs instead of conventional lamps, making them accessible to a broad market.
Depending on the ambient light conditions and the distance to the projection surface, requirements differ for the light source. With 12 new products, Osram is now able to offer three different power classes for RGB solutions in deep blue (440 nm), blue (456 nm), converted green (520 nm) and amber (614 nm). In the lowest power class, two chips of the same color per component provide projector brightness of up to 1,500 ANSI lm. In the mid-power class, four chips of the same color per component can achieve 2,500 ANSI lm. While in the highest power class, six chips of the same color per LED can achieve more than 3,000 ANSI lm. As a result, products from the Osram Ostar Projection Power family emerge as a clear alternative to the high-pressure discharge lamps previously used in projectors above 2,000 ANSI lm.
This leap in performance was achieved, among other things, by improved chip and package technology. The developers at Osram have fundamentally modified the individual LED chips allowing them to be electrically connected in a series on the copper board. The system designer benefits not only from a significantly lower operating current (with the same power consumption) and reduced complexity of the LED driver but also from the much simpler contacting of the component. In addition, direct coupling of the LEDs to a heat sink is possible – without additional isolation costs.
The mechanical design remains largely unchanged compared to previous products enabling fast and uncomplicated exchange of the products in existing projector systems.
“With products from the Osram Ostar Projection Power family, we have successfully crossed the 3,000 ANSI lumens barrier using LED technology,” explains Wolfgang Schnabel, Product Manager in the Visualization & Laser division at Osram Opto Semiconductors. “Our customers can easily integrate the new components in their desired power class into their system design and replace conventional lamps with state-of-the-art LED systems.”
MYIR introduces a cost-effective MYC-YA157C CPU Module powered by ST’s STM32MP1 microprocessor which features dual-core Arm Cortex-A7 operating at up to 650MHz and an embedded Cortex-M4 core operating at up to 209MHz. The module is ready to run Linux OS and targets a wide variety of applications like industrial control, consumer electronics, smart home, medical and more other energy-efficient applications which require rich performance and low power.
Measuring 45mm by 43mm, the MYC-YA157C CPU Module is a compact System-on Module (SoM) that combines the STM32MP157 processor (STM32MP157AAC3 by default), a dedicated Power-Management IC STPMIC1 also from STMicroelectronics, 512MB DDR3, 4GB eMMC as well as an integrated GigE PHY chip. A number of peripherals and IO signals are brought out through 1.0 mm pitch 164-pin stamp-hole (Castellated-Hole) expansion interface to make the module an excellent embedded controller for system integration.
MYIR offers MYD-YA157C development board for evaluating the MYC-YA157C CPU Module, its base board has explored a rich set of peripherals and interfaces such as RS232, RS485, USB Type-C DRP, USB2.0 HOST, Gigabit Ethernet, WiFi/Bluetooth, CAN, Micro SD Card Slot, JTAG, RGB888 based LCD/ HDMI, MIPI-DSI, etc.
The MYD-YA157C is delivered with necessary accessories, detailed documentation, optional MY-CAM002U Camera Module and MY-TFT070CV2 LCD Module which makes it ideal for evaluating and prototyping based on ST’s STM32MP1 microprocessor.
MYIR also offers design services to customize the base board according to customers’ requirements. Different SoM configurations such as other STM32MP1 CPU models, RAM or Flash configurations, industrial or commercial grade can also be customized.
Based on Linux 4.19.9 kernel, MYIR has provided abundant software resources for Yocto 2.6 based MYIR MEasy-HMI system, Yocto 2.6 based ST Weston system, Ubuntu 18.04 system and MYIR MEasy-IOT system including kernel and driver source code, STM32CubeProgrammer and STM32CubeMX tools to enable users to start their development rapidly and easily.
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