FRAMOS, a global partner for vision technologies, now offers the new ECX335S microdisplay series from Sony Semiconductor Solutions. Featuring outstanding brightness, contrast and resolution plus a wide viewing angle, this solution is suited to the fast-growing market of augmented reality (AR) devices. These include head-mounted displays (HMDs), electronic viewfinders (VFs), and small monitors. The ECX335S is an OLED panel module with active matrix color design, exceptional brightness of up to 3,000 cd/m², Full HD resolution with 1,920 x 1,080 RGB pixels, and a diagonal of 1.8 cm (0.71 inch). Its power consumption is low even at a frame rate of 60 fps.
AR applications require brightness in excess of 1,000 cd/m². This means the OLED microdisplay must have a nominal value of at least 3,000 cd/m², to allow for transmission losses during projection. Through a clever combination of enhancements, Sony Semiconductor Solutions has increased the brightness of the new ECX335S microdisplays by a factor of three compared to previous models, while maintaining the same operational life. With its brightness characteristics, extremely small form factor (21.44 mm x 15.62 mm) and a contrast ratio of 100,000:1, this module will continue to spur innovative AR solutions. Information levels in the HMD or VF are rich in contrast and blend seamlessly into the real world, creating a “real” AR experience.
With a code size of 1KB on an ATtiny13A MCU, this tiny module measures voltages up to 22 volts and current up to 5 amps. This project is published by Tirdad Sadri Nejad. He writes:
There are a lot of so-called “USB doctor” modules which are used for monitoring currents flowing through a USB connection. They are used for cable or charger testing, quick charge detection and load current consumption measurements. They’re cheap of course and someone may ask why should we build one? If you can do it better, then do it. So what’s better about my design?
Self-calibration: You don’t need to know the exact resistor values used for voltage dividers. Just use a proper divider to map your desired voltage range into 0~1.1v range (1.1v is the internal V-ref of ATtiny13. The feature we needed it for). after that all you need to do is to connect the module to a precise 5v supply while holding the onboard button. the device starts up and shows “C” character on the display, calculates the divider values itself and saves them in the internal e2prom. So you just need to do it once.
Various display options: Using the button, you can switch between current display, voltage display and both. It is possible to save the preferred display on e2prom for startup.
A 1KB code challenge: Despite there are better options than using 2 chips (1 micro controller + 1 display driver), I like the discrete designs. I had to implement a display library too. The display driver is universal and you can use it for any other microcontroller that supports an ANSI C compiler! read the libraries provided below.
The design is based on an ATtiny13A microcontroller, a TM1637 LED driver and a 0.033ohms current sense resistor. the 1.1v ADC voltage reference on the ATtiny came quite handy for better precision.
I had to get rid of floating-point calculations. despite the voltage divider and the values shown on the display may seem to have radix points, they don’t. The values are calculated as mA and mV and then a point is placed in the display at proper location. so there was no need to calculate float values.
Self-Calibrating USB Voltage/Current Meter – [Link]
This small constant current LED driver Nano shield has been designed using CAT4104 IC from ON semiconductor. Its 4 channel LED driver. The board has provision to mount 20 SMD 1206 LEDs. The LED can be RED, GREEN, BLUE and WHITE. Reduce the number of LED to 12 if White LEDs are used, as white LEDs are 3-5V and total series voltage should not exceed 12V. CAT4104 provides four matched low dropout current sinks to drive high−brightness LED strings up to 175 mA per channel. The LED channel current is set by an external trimmer potentiometer connected to the RSET pin. The LED pins are compatible with high voltage up to 12V. The EN/PWM logic input supports the device enable and high-frequency external Pulse Width Modulation (PWM) dimming control. Thermal shutdown protection is incorporated in the device to disable the LED outputs whenever the die temperature exceeds 150°C. Nano LED shield can be used to develop intelligent lighting for Automotive and Architect since PWM pin of LED driver connected to D9 PWM pin of Arduino. The EN/PWM pin has two primary functions. One function enables and disables the device. The other function turns the LED channels on and off for PWM dimming control.
The device has a very fast turn−on time (from EN/PWM rising to LED on) and allows “instant on” when dimming LED using a PWM signal. Accurate linear dimming is compatible with PWM frequencies from 100 Hz to 5 kHz for PWM duty cycle down to 1%. PWM frequencies up to 50 kHz can be supported for duty cycles greater than 10%. PWM pin connected to D9 of Arduino.
Note: Replace D1, D6, D11, D16, D2, D7, D12, and D17 with 0 Ohms SMD 1206 Resistor in case of white LED used.
Features
Input supply 12V DC
LED Load 750mA (4 Channel)
Constant Current Adjustable with help of Trimmer Potentiometer
Thermal Protection Shutdown
PR2 Trimmer Pot Provided to Adjust the Constant Current 80mA to 750mA
D9/PWM Of Arduino Connected
PR1 Trimmer Pot Connected to A0 Pin of Arduino Nano for Dimming Application
Nixie tubes are always fascinating. Nowadays they are mostly used for clock displays, such as the project in the May/June 2016 issue of Elektor. The ‘Nixie’ bargraph tubes for analogue readout in the form of a column of light are less well known. Strictly speaking, they are not Nixie tubes because they do not display numerals, but they have the same warm retro allure because they are also filled with neon gas. The thermometer described here uses a Russian IN-9 tube and is a nice alternative to the usual clock projects.
Original publication: Elektor Magazine 5/2018 (July & August) on page 30
Author: Ilse joostens
Original article production number: 160705
Semi kit available, see PRODUCTS below
Free download expires: Friday 27 March 2020
Like what you’re seeing? Then go to the article page and download a pdf copy of the full, original article. Downloading is free from Friday 20 March to Friday 27 March 2020.
In the DC regime, only one definition of the value of a voltage is possible, this value is unambiguous and is determined by the difference between the reference value 0 V and the flat line figure of the DC signal.
In the AC regime, however, it can lead to confusion to speak of only one value for the voltage. From a simple sine waveform, we can at least list indeed four different definitions of voltage:
fig 1: Illustration of the peak, Average and RMS values
The peak value corresponds to the difference between the reference (which is the value where the AC signal oscillates around) and the maximum value of the signal. The peak-to-peak value is the peak value multiplied by a factor 2, it corresponds to the total vertical width of the signal.
In Figure 1, we have also highlighted the Average and RMS values in red, which we will be focusing on in the following of this tutorial.
The two sections developed in this article will separately present the Average and RMS values, we will see how they are defined, how to determine them and finally we will see what is special about the RMS value.
Average Voltage
For an elementary symmetrical sine, triangle, square or sawtooth waveform (see Figure 2 and AC Waveform tutorial), it is unclear to speak of the average voltage value, that we will note A in the following. Indeed, these types of signals are during half of their period positive and negative during the other half. In other words, the signals are 50 % of the time above the horizontal axis and 50 % under it.
From that observation, it is easy to understand that if we consider the average value of any of these signals on a full period, it is equal to 0, regardless of the peak value, and therefore not relevant.
fig 2: Elementary sine, triangle, square and sawtooth waveforms
We can demonstrate this result by explaining how to calculate the average value. For a finite set of values, the averaging process consists of summing all the values (V1, V2, V3…) and dividing them by the cardinal number N of the set (how many values there are in the set):
For an analog signal, however, it is impossible to sum all the instant values, also called mid-ordinates, that the signal takes during a period simply because there is an infinity. Instead of summing, we use the integration operation:
eq 1: Average of an AC signal V(t) taken for a full period
Equation 1 is the average of the signal V(t) taken between the times 0 and T, that is to say, a full period. The term ∫V(t)dt gives the value of the area between the curve V(t) and the reference of 0 V. Because the integration operation is linear, this term can be split in two:
For an elementary waveform such as presented in Figure 1, we can see that the first and second terms of this formula are equals but of opposite signs, therefore the average value is equal to 0.
In order for the average value of such signals to make sense, we prefer to consider separately the half positive and negative periods, which some their values are respectively highlighted in red and green in the following Figure 3:
fig 3: Some instant-values for the positive half-period (in red) and negative half-period (in green) of a sine waveform
Similarly to Equation 1, we can define separately the average values for the positive half-period (A+) and negative half-period (A–):
eq 3: Averages of an AC signal V(t) taken for the positive (+) and negative (-) half-periods
The value of A+ and A– depends on the signal we are dealing with and their respective peak values (Vp). We list below the absolute value |A| of A+ and A– for the most common elementary and symmetrical AC signals:
Sine waveform: |A|=0.637×Vp
Triangle waveform: |A|=0
Square waveform: |A|=Vp
Sawtooth waveform: |A|=0.5×Vp
We can conclude this section by saying that when we want to average a signal, we need to give the precision if the process is done on a full period or a smaller value. For the elementary and symmetrical AC signals, averaging on a full period always gives the result 0 V regardless of the frequency, peak value or period. For this reason, it is more appropriate to average these signals during their half-periods.
RMS Voltage
RMS stands for Root Mean Square, is it a similar operation to the average value presented previously but the instant values are instead squared and the total fraction is rooted:
For the same reasons as stated previously, we use the integration operation to define VRMS for an analog signal:
eq 4: RMS value of an AC signal V(t) of period T
Unlike the average value, the RMS value is always defined for a full period of the signal, there is indeed is no possible confusion to determine this value.
As an example, let’s determine the RMS value of a sine waveform of peak value Vp and angular pulsation ω V(t)=Vp×sin(ωt). We note f the frequency that satisfies f=ω/2π and T=1/f the period.
First of all, we compute the integral term that we note I:
We use the trigonometric identity sin2(x)=(1-cos(2x))/2 to continue:
Evaluating the bracket term between 0 and T gives 2π/ω=T. Therefore, the integration term is finally equal to (πVp2)/ω. From Equation 4 we can see that we still need to multiply by 1/T which leads to [(πVp2)/ω]×[ω/(2π)]=Vp2/2 for the term under the root.
Finally, after taking the root, the final expression for the RMS value of a sine waveform is given by:
We list below the RMS values that can be computed by the same method as the sine example above for the elementary and symmetrical signals stated in the previous section:
Sine waveform: VRMS=Vp/√2
Triangle and Sawtooth waveform: VRMS=Vp/√3
Square waveform: VRMS=VP
It is important to note that VRMS>|A|, the RMS value is always greater than the absolute value of the average.
What is fundamental to understand the RMS value is that it creates a link between the DC and AC regimes according to the following Figure 4:
fig 4: Similarity between the AC and DC regimes
The RMS values of voltage and current are the values that develop the same power across a resistance in a DC regime.
Conclusion
The average and RMS values can easily be measured by modern voltmeters or oscilloscopes and provide information about an AC signal.
The numerical approach for the average consists of summing all the values of a signal and divide the sum by the number of values. For real signals, we prefer to use the integration operation which is an extension of the sum for an infinite set of values.
Two definitions are possible for the average value, depending on if the average is done on a full period or a half-period. Symmetrical signals are characterized by an average value of 0 on a full cycle. The average value on a full cycle is different from 0 only if a DC component is present in the signal or if the signal is not symmetrical around a horizontal reference. Averaging on a half-period can also be done in order to characterize differently symmetrical signals.
The RMS value is defined similarly to the average value but each value of the sum is instead squared and the final result is rooted. The root-mean-square value is always higher than the absolute value of the average and established a link between the AC and DC regimes, which is why it is particularly used by engineers.
Beetle is one of the smallest Arduino Leonardo board. It derives its core notion from minimalism without compromising functionality.
It comes with Atmel AtMega32u4 ( datasheet) @16MHz clock time and has expanded amounts of interfaces: 10 digital pins, 5 analog pins, and 4 pwn pins. To further make it user-friendly, it is compatible with Micro USB so that direct programming and testing is no longer a headache. Select “Arduino Leonardo (tools >board > Arduino Leonardo in Arduino IDE), the ATmega32U4 comes pre burned with a bootloader that allows you to upload any new code that is applicable to Arduino Leonardo.
As the smallest Arduino Leonardo, it enjoys similar powerful functionalities. Beetle aims to solve problems of the low-cost controller, ease-of-using properly, and to provide a low-cost solution for disposable projects, such as DIY projects, workshops, gift projects, E-Textiles and educational. For students and makers who can not afford too much on hardware purchasing, Beetle can be a great solution for them.
Features
20mm X 22mm compact size
Direct downloading and testing via Micro USB
V-shaped large-size gold-plated IO ports make it convenient for the user to twist wires upon, and can also be directly sewn on clothes with conductive thread.
Two honeycomb shape gold-plated power interface
Magic light blue soft BLINK indicator
Specification
Microcontroller: ATmega32u4
Clock Speed: 16 MHz
Operating Voltage: 5V DC
Digital I/O Pins: 10
PWM Channels: 4
Analog Input Channels: 5
UART: 1
I2C: 1
Micro USB: 1
Power Ports: 2
Flash Memory: 32 KB of which 4KB used by bootloader
The project published here is based on SSM2019 IC which is a latest-generation Pro audio preamplifier. A female XLR connector is provided to connect differential Micro-phone. Circuit also provides Phantom power input, combining SSM preamplifier design expertise with advanced processing. The result is excellent audio performance, the attached trimmer potentiometer helps to adjust the output gain. The SSM2019 is further enhanced by its unity-gain stability. Key specifications include ultra-low noise (1.5 dB noise figure) and THD (<0.01% at G = 100), complemented by wide bandwidth and high slew rate. Applications for this low-cost device include microphone preamplifiers and bus summing amplifiers in professional and consumer audio equipment, sonar, and other applications requiring a low noise instrumentation amplifier with high gain capability. Z1 to Z4 provide transient overvoltage protection for the SSM2019 whenever microphones are plugged in or unplugged. Gain level adjustable 0 to 60dB. CN2 connector for supply input and audio output, CN4 Female XLR connector for Micro-Phone input, CN1 Phantom Power input.
The project published here is a high-voltage adjustable regulator with an output 48 V DC from an input supply of 125V DC. The circuit is capable to drive load current up to 500mA. This regulator circuit designed for use in high-voltage applications where standard bipolar regulators cannot be used. Excellent performance specifications, superior to those of most bipolar regulators, are achieved through circuit design and advanced layout techniques. As a state-of-the-art regulator, the TL783 device combines standard bipolar circuitry with high-voltage double diffused MOS transistors on one chip, to yield a device capable of withstanding voltages far higher than standard bipolar integrated circuits. Because of its lack of secondary-breakdown and thermal-runaway characteristics usually associated with bipolar outputs, the TL783 maintains full overload protection while operating at up to 125 V from input to output. Other features of the device include current limiting, safe-operating-area (SOA) protection, and thermal shutdown.
Even if ADJ is disconnected inadvertently, the protection circuitry remains functional. Only two external resistors are required to program the output voltage. An input bypass capacitor is necessary only when the regulator is situated far from the input filter. An output capacitor, although not required, improves transient response and protection from instantaneous output short circuits. Excellent ripple rejection can be achieved without a bypass capacitor at the adjustment terminal. Output voltage fixed 48V DC but it is adjustable by changing the value of resistor value R6, refer to datasheet for the formula to choose the appropriate value of R6. LT783 and transistors require a large size heat sink.
This is an ESP8266 based coronavirus tracking project from “Volkan Unal” on github.com. The tracker can be configured to display the details of your own country.
Instructions
1- Change your wifi information from WifiConnect.h file
Micsig’s STO1000E 2/4-channel oscilloscopes include 70Mpts memory, 1GSa/s sampling, 130,000wfm/s refresh rate, and a 7.5Ah Li battery for extended field use.
Saelig Company, Inc. has introduced the Micsig STO1000E PLUS series of two- and four-channel battery-powered portable oscilloscopes, which offer bandwidths of up to 150MHz. The three models in the series are: STO1102E PLUS 2-channel 100MHz, STO1152E PLUS 150MHz 2-channel, and STO1104E PLUS 4-channel 100MHz. Each oscilloscope includes 70Mpts memory, 1GSa/s sampling (single channel), 130,000wfm/s refresh rate, and a 7.5Ah Li battery for extended field use.
These innovative portable instruments are a development of Micsig’s range of tablet oscilloscopes and combine an 8” touch screen (touch, drag, and swipe) with ‘button & knob’ operation. An external USB mouse can also be connected for additional control choices, with an internal software pop-up keyboard provided for data entry. The built-in HDMI output adds educational and demonstration possibilities, and an auto-calibration function ensures measurement accuracy. Sophisticated waveform triggering techniques include: Edge, Pulse Width, Logic, Video, Runt, Time Out , Nth Edge, Slopetime, and Serial Decode. A screen capture button provides a quick way of saving waveform images for later review or report writing.
Included as standard are two P130A 200MHz x10 passive probes and an external 12V power adapter. STO1000E PLUS oscilloscopes can make 31 types of automatic measurements, and decode a selection of serial protocols, including UART, CAN, LIN, SPI, I2C, 1553B, and ARINC429. I/O provisions include Wi-Fi, LAN, HDMI, USB Host, USB Device, DC Power, and Aux out. 8GB of internal data storage is included for data files that can be transferred to a PC via a USB connection, LAN, or WiFi.
The oscilloscope features a built-in prop stand for easy viewing. When the oscilloscope is connected to a LAN or WiFi network, live screen images can be transmitted to an external projector. The scope can also be remotely PC-controlled via WiFi, LAN, or USB, and also via an Android mobile device.
Made by Shenzhen-based Micsig, a leading provider of battery-powered portable and handheld oscilloscopes since 2004, the STO1000E series of oscilloscopes are available now from Saelig Company, Inc., Fotric’s authorized North American distributor.