Infineon Technologies introduces the new OptiMOS™ IR3826(A)M integrated point-of-load DC-DC voltage regulator. It is a fully integrated and highly efficient device in two versions (IR3826AM for 16 A and IR3826M for 23 A) for applications such as netcom router and switches, datacom, telecom base stations, server and enterprise storage.
The voltage regulator can operate from an input voltage of 12 V (5 V to 17 V) and provide up to 16 A or 23 A continuous current. It enables high-switching-frequency operations with enhanced efficiency and reduced power losses compared to previous generations of Infineon’s offering. Furthermore, the device supports high switching frequency of up to 1.5 MHz for small PCB size and less capacitors.
The IR3826 efficiency vs. output current. VIN = 12 V, FSW = 600 kHz, natural convection, TA = 25 °C.
Both current ratings are offered in PQFN package with 5 mm × 6 mm footprint for easy scalability. Parts are pin-compatible to the previous product offerings to allow risk-free efficiency upgrade with minimum design effort.
The IR3826(A)M solves the heat challenge without or with minimum airflow in thermally constrained application designs such us 3.3 V or 5 V supply voltages. Additionally, it supports applications that operate with high ambient temperature, e.g., 85 °C for telecom.
The state-of-the-art PWM Gen 3 engine of the devices allows operation with fixed frequency to reduce noise in multi-rail telecom or high-end Netcom applications, like base stations.
The devices are fully RoHS2 compliant without an exemption to accommodate future regulations.
Availability
High volume production has started. Evaluation boards are also available.
Texas Instruments’ power-path management solution features 20 mA termination and 1 A boost operation
Texas Instruments’ BQ25619 integrates charge, a boost converter, and voltage protection in a single device. It offers ultra-low termination current for switching chargers to charge wearable devices by full-battery capacity. The BQ25619 low quiescent current reduces battery leakage to 6 µA in ship-mode, which conserves battery energy to double the device’s shelf life. The device is a highly integrated 1.5 A switch-mode battery charge management and system power-path management device for Li-Ion and Li-polymer batteries. It features fast charging with high input voltage support for a wide range of applications including wearables and earphone charging cases. The low impedance power-path optimizes switch-mode operation efficiency, reduces battery charging time, and extends battery run-time during the discharging phase. The input voltage and current regulation, low termination current, and battery remote sensing deliver maximum charging power to the battery. The solution is highly integrated with input reverse-blocking FET (RBFET, Q1), high-side switching FET (HSFET, Q2), low-side switching FET (LSFET, Q3), and battery FET (BATFET, Q4) between the system and battery. A bootstrap diode is integrated for the high-side gate drive to simplify the system design. The I2C serial interface with charging and system settings makes the device a truly flexible solution.
The BQ25619 supports a wide range of input sources, including a standard USB host port, USB charging port, USB-compliant high voltage adapter, and wireless power. The charger is compliant with USB 2.0 and USB 3.0 power specs with input current and voltage regulation. The device takes the result from a detection circuit in the system, such as a USB PHY device. The BQ25619 integrates a buck charger and boost regulator into one solution with a single inductor. The boost-mode supplies 5 V (adjustable 4.6 V / 4.75 V / 5 V / 5.15 V) on the PMID-pin and is used to save BOM and charge another battery by the control of PMID_GOOD. The PMID_GOOD pin is used to drive the external PMOS FET to disconnect boost output PMID from the attached accessories. The power-path management regulates the system slightly above battery voltage but does not drop below the 3.5 V minimum system voltage (programmable) with the adapter applied. With this feature, the system maintains operation when the battery is completely depleted or removed. When the input current limit or voltage limit is reached, the power path management automatically reduces the charge current. As the system load continues to increase, the battery starts to discharge the battery until the system power requirement is met. This supplement-mode prevents overloading the input source.
Features
Single-chip solution to charge wearable accessories from an adapter or battery
Single input supports USB, high-voltage adapter, or wireless power
Narrow VDC (NVDC) power-path management
Flexible I2C configuration and autonomous charging for optimal system performance
High integration includes MOSFETs, current-sensing, and loop compensation
Low RDS(ON) 19.5 mΩ BATFET minimizes charging loss and extends battery run-time
Low battery leakage current in ship-mode (7 µA), system standby (9.5 µA)
High accuracy battery charging profile
Applications
Consumer wearables, smartwatches
Personal care and fitness
Headsets/headphones
Earbuds (true wireless or TWS) charging cases
Hearing aids charging cases
The BQ25619 initiates and completes a charging cycle without software control. It senses the battery voltage and charges the battery in three phases, including pre-conditioning, constant current, and constant voltage. At the end of the charging cycle, the charger automatically terminates when the charge current is below a preset limit, and the battery voltage is higher than the recharge threshold. If the fully charged battery falls below the recharge threshold, the charger automatically starts another charging cycle. The charger provides various safety features for battery charging and system operations including battery negative temperature coefficient thermistor monitoring, charging safety timer, and overvoltage and overcurrent protections. Thermal regulation reduces charge current when the junction temperature exceeds +110°C. The status register reports the charging status and fault conditions. With I2C, the VBUS_GD bit indicates if a good power source is present, and the INT output immediately notifies the host when a fault occurs. The device provides the QON pin for BATFET enable and reset control to exit low power ship-mode or full system reset function. The BQ2619 device is available in a 24-pin, 4 mm × 4 mm x 0.75 mm thin WQFN package for easy layout.
Despite their differences, we have seen in the previous tutorials about class A, class B and class AB amplifiers, that these three classes are linear or partially linear since they reproduce the shape of the signal during the amplification process. This is due to the fact that they use at least 50 % of the input signal, therefore a combination of two transistors in a push-pull configuration reproduces 100 % of the signal.
However, some amplifiers can be biased in such a way that they are not linear at all, this is the case of class C amplifiers that this tutorial focuses on. In the first section, the structure of such a configuration will be presented in detail since the output stage of class C amplifiers differs radically from the regular linear classes. Generalities will be also mentioned in this paragraph. In the following part, we will see how this type of amplifier works by focusing on the output/input characteristic. A third section will deal about the efficiency of the class C biasing architecture. Finally, a last section will show how this special amplifier can be used in modern electronics.
Presentation of the Class C amplification
As we have seen for class AB amplifiers, class C are not defined by a single operating point but rather an operating zone. This fact is illustrated in the Figure 1 below :
fig 1 : Operating zone of class C amplifiers
Since this operating zone extends beyond the class B operating point, which represents a 78.5 % efficiency and a 180° conduction angle, class C amplifiers are therefore characterized by a very high efficiency between 78.5 % and 100 % as we will detail more in the third section. Moreover, their conduction angle is very low, between 0° and 180°, which means that they conduct less than half of the signal. As we will see later on, it is precisely this fact that makes them non linear.
Class C amplifiers are mostly used for high frequency applications, they generate many harmonics that must be filtrated in order to faithfully reproduce the input signal. This filtration can be done for example with an RLC circuit as presented in the Figure 2 that represents the basic structure of class C amplifiers :
fig 2 : Basic structure of a class C amplifier
The aim of the RLC circuit, also known as “circuit stopper” is to eliminate the undesired frequencies and to only keep the fundamental frequency f1 of the input signal.
In practice, the load is coupled to the resonant circuit with a transformer as presented in Figure 3.
fig 3 : Transformer-coupled class C amplifier
As already presented during the class A amplifier tutorial, this transformer-coupled configuration ensures that the load is isolated from the power supply and it is also used to realize an impedance matching. Moreover, the base is biased through a voltage divider network. In the following section, we will always refer to the Figure 3 circuit.
Class C functioning
The first goal of this section is to graphically represent the output current IC. In order to do that, we will use the transfer characteristic IC=f(VBE) where VBE is the base-emitter voltage difference.
We will admit that this transfer characteristic is approximately linear by segment such as shown in Figure 4. The first segment is between the origin and a threshold value VT and has a slope of zero. The second segment continues from VT and has a slope of gm (the transconductance).
fig 4 : Graphical representation of the output current
As we can see from Figure 4, the output current can be described as “pulsed”. It can be characterized by two important parameters : the peak current ICM and the δ values that delimits the pulse signal. It is interesting to note that the conduction angle is equal to 2δ and represents the electrical angle in which the output current is not equal to zero.
If the output stage of the class C amplifiers does not have a circuit stopper but only a load, both the current and voltage are pulsed such as shown in Figure 4, this functioning mode is called the untuned mode. As explained more in detail in the last section, a proper choice of the value of the product L×C can lead to a functioning mode in tuned mode. In this mode, a particular frequency of the pulses is filtrated by the RLC circuit in order to regenerate the sine of the input signal, therefore performing a faithful amplification.
If we consider the input signal to be of the form Vin(t)=VI×sin(2πf1t), an important formula can be given in Equation 1 and links the maximal value of the output current ICM to the amplitude of the input signal VI :
eq 1 : Expression of the maximal value of the output current
From this equation, we can understand that the conduction angle influences greatly the amplification process. The graph below represents the evolution of ICM for a conduction angle in the class C interval ]0° ; 180°[, that is to say for a δ value in the range ]0° ; 90°[.
fig 5 : ICM=f(δ). Plotted with MatLab®
We can clearly note a fast decrease of the maximal value of the output current when the conduction angle increases. This graph gives an overview of the efficiency of the class C configuration : the smaller the conduction angle, the higher the output current.
In the tuned functioning mode, the output voltage can simply be written under the form Vout=Vsupply+k.Vsupply×sin(2πf1t+π). It is amplified by a factor k.Vsupply, phase shifted of π rad and presents an offset equal to Vsupply. Note that k is called the transformer coupling factor and is in the range [0;1]. This factor highlights the quality of the transformer used, for example a perfect transformer has a coupling factor of 1.
Efficiency of class C amplifiers
The method and steps to demonstrate the formula of efficiency η for class C amplifiers involves integral calculus and is not shown in this tutorial. The formula linking the efficiency to the parameters δ and k is given in the Equation 2 below :
eq 2 : Efficiency of a class C amplifier
It is interesting to visualize the dependency of the efficiency on both parameters in a graph given below :
fig 6 : Efficiency of class C amplifiers. Plotted with MatLab®
Best efficiencies are achieved with an ideal transformer where k=1. Moreover, we can highlight that if k=1 and the conduction angle is 180° (δ=90°), we are in a class B configuration and we recognize the maximal efficiency of 78.5 %.
A theoretical maximal efficiency of 100 % could be reached with k=1 and a zero conduction angle. However, for such values, the useful power delivered to the load is zero and therefore such efficiency cannot be achieved.
An application of class C amplifiers : the frequency multiplier
An interesting aspect of the circuit shown in Figure 3 is that the resonance circuit can be matched to the frequency of the input signal but as well to one of its harmonics. An harmonic is a multiple of the frequency f1 of the input signal of the form n×f1 with n an integer.
In order to realize this frequency match, the product L×C must satisfy the relation proposed in Equation 3 :
eq 3 : Frequency match relation
Since the collector current, as seen in Figure 4, is a pulse signal, its frequency spectrum already includes the fundamental frequency f1 and the following harmonics f2=2×f1, f3=3×f1, … If a frequency match is established for a certain harmonic, for example f3, this particular frequency will prevail over all the others. In this case, the voltage output is a sine signal of frequency f3 and amplitude RL×IC.
The Figure 7 below summarizes this function of frequency multiplier :
fig 7 : Frequency multiplier principle
Conclusion
Class C amplifiers present higher efficiencies than class A, B or AB. However, their conduction angle is very low between 0° and 180°, meaning that they conduct only a fraction of the signal. This fact leads to a poor linearity of the amplifier, both voltage and current outputs are very distorted because they present a high number of harmonics.
In order to overcome this problem, the output stage of a class C amplifier must be wired to what is commonly known as a stopper circuit. This filter consists of a parallel RLC arrangement that selects only the desired harmonic to be amplified, if a faithful amplification is needed, the RLC circuit is matched to the fundamental frequency of the input signal. The inductance is generally replaced by a transformer in order to properly isolate the load from the supply and to match the impedance.
We have seen in the second section that two functioning modes can appear :
If the stopper circuit does not match any particular harmonic of the initial signal, the output signals are pulsed : this is the untuned mode.
If the stopper circuit is tuned to the fundamental frequency or any harmonic, the class C amplifier becomes linear and the output signals are sine waves : this is the tuned mode.
Later on, the efficiency of class C amplifiers has been discussed and we concluded that high efficiencies are more likely to happen for ideal transformers with coupling factors that tend to 1 and low conducting angles that tend to 0. However, no useful power can be delivered to the load with such a conducting angle. In practice, a good compromise is to set the angle to 120° to obtain both a good efficiency and a high enough fraction of the input signal conducted.
Finally, we have seen that class C amplifiers can be tuned to any higher harmonic of the input signal in order to realize a frequency multiplier circuit. For this reason, class C amplifiers are appropriate in the design of frequency synthesizers and telecommunication applications.
Specs for Intel’s NUC 8 rugged mini PC and 3.5-inch dashboard have been released. The fanless NUC 8, code-named Chaco Canyon, runs Windows or Linux on low-power (6W TDP) dual-core and 1.1 GHz/2.4GHz Celeron N3350 from Apollo Lake with dual HDMI ports, 4GB RAM, soldered down 64GB eMMC, and M.2 22 x 80 key M slot for PCIe x4 NVMe.
The recently revealed mini PC designed for greater reliability has a ventless design for minimizing particle intrusion, a wide-range DC input (12-24V) with transient voltage suppression, compliance with EMC/RF standards, a delayed AC start and DC over-voltage protection. It offers ACPI power management and hardware monitoring. According to Intel, the PC was designed to fit for round-the-clock tasks “…the Intel NUC 8 Rugged is built to last and qualified for 24×7 sustained operations – a critical feature for IoT and commercial operations. Fanless and ventless, the Intel NUC 8 Rugged isn’t afraid to get a little dirty”.
The system is equipped with dual HDMI ports – HDMI 2.0a port (that supports up to 3840 x 2160 pixel display resolution, 7.1 multi-channel digital audio) and HDMI 1.4 port with CEC and EDID. It has an internal 4-lane eDP display connector, an analog audio jack, multiple mounting options including VESA mounting holes, zip-tie indentations, and 3rd party DIN-rail bracket. It has support for eight USB connections with dual rear USB 2.0 ports, front and back USB 3.0 ports and additional headers (1 x 3.0, 2 x 2.0). It also has support for a Kensington lock with base security, an internal RS-232 interface and a front-panel header. There is an M.2-based Intel Dual Band Wireless AC 3168 module, GbE ports, internal antennas, Bluetooth 4.2, Intel Gigabit LAN for wireless connectivity, and available punch-outs for adding external antennas.
The products are aimed at applications in edge analytics, quick service restaurants, hospitals, medical clinics for mobile pedestrian computing, operator consoles in manufacturing environments, digital signage and IoT. The mini PC, as well as the NUC8CCHB baseboard-based SKU with a 3.5-inch form factor, is due to ship by the end of the month.
The full kit is available for pre-sale at various locations for $248 plus $10 shipping but pricing or availability info has not been listed yet for the NUC8CCHB baseboard model. However, the 146 x 102 mm baseboard model adds a 19VDC, 65W power adapter and like the mini PC kit, offers a warranty of 3 years. For full specs check out the NUC 8 Rugged product brief (PDF) and the Ark page.
The internet as we knew it, a few years back, was being run by humans; the majority of everything that happens over the internet – the messages, the data, the communication was between people. But this is changing gradually; a new category of devices that do not have any communication between humans is beginning to take over the internet. These machines talk to other machines and are just simply being referred to as “Things”.
However, as the need to connect these devices arises, there becomes an increasing demand for a place to store, process and send information within these devices. With millions of devices connected to the internet, we see an increasing potential of tapping and processing efficiently the data acquired from them.
Cloud computing has become a generally appreciated way of running and developing tech solutions especially the IoT which depends directly on the internet. Cloud platform for IoT brings together the capabilities of cloud platform and IoT devices as service over an end-to-end platform.
There are already plenty of cloud services available for the Internet of Things, many tech companies now capitalize on providing options for deploying IoT applications on the go. Here is a list of the top 5 IoT cloud platforms that exist today:
1. Amazon Web Services IoT platform
No matter the kind of cloud-based project you have in mind, the AWS platform guarantees almost a 100% probability of supporting it. Because they have put in a lot of effort into innovation and building features over the years, the AWS platform probably has the most comprehensive set of tools available. The platform supports HTTP, WebSockets and MQTT. Amazon Web Services owned by Amazon allows users to host and manage services on the internet. It gives users much ease with collecting data from internet-connected devices.
The AWS offers a lot of benefits for users of this platform which includes database management, infrastructure management, cloud base data storage solutions, and application transfer. The major features of t his platform are:
Authentification and encryption
Device management
Device shadow
Secure gateway for devices
It is open-source and flexible and has good integration with IAAS offering but the AWS platform is not secure for hosting critical enterprise applications and there is a heavy learning curve for AWS. Pricing, however, is a bit on the high side here.
2. Microsoft Azure IoT hub
Microsoft is another giant in the IoT space taking cloud services very seriously. The Microsoft Azure has multiple services for IoT solutions that enhance productivity and profitability with pre-built connected solutions. It can also easily analyze untapped data or act on new data to transform business. It supports HTTP, MQ Telemetry Transport, and Advanced Message Queuing Protocol. Its features include:
Rich integration with SAP
Dashboards and visualizations
Easy device registry
Real-time streaming
While the Azure is secure, scalable and highly available, it does not have supports for bugs and also requires heavy management.
3. IBM Watson IoT Platform
IBM Watson is another giant for IoT cloud service. They provide easy apps and interfaces that make their cloud services as accessible as possible to beginners. The IBM platform has a secure communication connection, cognitive systems and offers a real-time data exchange. Recently, it added data sensor and weather data service to what to improve its customers’ service. Again, while it can handle huge quantities of data, it takes a lot of time for integration. It also has a high switching cost and needs a lot of maintenance.
4. Google Cloud Platform
Google’s IoT cloud platform is also one of the best platforms we currently have with a focus on making things fast and easy. It has an end-to-end- platform for IoT services to help scale your business. You can take advantage of Google’s heritage of machine intelligence, analytics, and web-scale processing to build IoT initiative.
Google provides efficient and scalable services, has huge storage capacity for data and cuts costs for server maintenance. It also has the ability to analyze big data and create business through a fully responsive, intelligent and protected IoT data. It takes lesser access time and gives the fastest input/output. However, the cons of this platform are that it has a limited programming language and most of its components are Google technologies.
Pricing is usually cheaper here than in Amazon and a few other platforms.
5. Oracle
This seems to be focusing on logistics and manufacturing operations but they also help to get your products to the market faster. They offer endpoint management, real-time IoT data analysis, and high speed messaging where for real-time message notifications. Its service to users includes an integrated secure and scalable service with real-time insight.
Meanwhile, like every IT system or service, each solution comes with its own advantages and disadvantages. When trying to choose the best platform for your IoT project, the end-to-end requirement and cost-benefit analysis between open-source and commercial solutions need to be considered.
Over the past years, live video streaming has undergone major technological advancements, triggering large scale implications in various commercial and industrial applications such as security surveillance system and online video broadcast. Advancements in video compression standards such as H.264 (AVC) and H.265 (HEVC) have made it possible for users to stream Full HD and 4K videos in real-time with high quality and detail, while taking up less bandwidth and processing time.
An application-specific processor does not provide the necessary compute resources to implement real-time encoding or multi-stream encode/decode at the highest level.
Implementing proprietary algorithms in programmable logic provides the flexibility and future enhancement to address the emerging market needs. These types of implementations typically have a programmable processor to handle application-level tasks, video codecs and manage the flow of data to the programmable logic devices.
Zynq UltraScale+ MPSoC is an ideal hardware platform to overcome all the challenges faced by the ASIC platforms. Unlike typical application processors, Zynq UltraScale+ MPSoC integrates heterogeneous high-performance ARM® multicore Cortex A53 CPU, Real-Time Cortex R5 CPU, Graphics Processor, Video Codecs, multiprocessing system with programmable logic cells. Quad-Core application processor equipped devices to deliver maximum scalability and are capable of offloading critical applications such as graphics and video pipelining, to dedicated processing HW codecs, along with a full complement of integrated peripherals, connectivity and a space for the programmability in FPGA.
The MPSoC supports the following various hardware codec features;
Simultaneous Encode and Decode through separate cores
H.264 high profile level 5.2 (4K@60fps)
H.265 (HEVC) main, main10 profile, level 5.1, high Tier, up to 4K@60fps
8 and 10-bit encoding
4:2:0 and 4:2:2 Chroma sampling
Low Latency Mode
Zynq Ultrascale+ MPSoC development Kit
SOM Solution offered by iWave:
iWave Systems have devised a SOM solution for implementing these advanced hardware Codecs using the latest FPGA integrated SoC technology which offers a lot of flexibility to the user by having the high-end ARM cores, graphic cores together with varying programmable logic density.
SOC: Xilinx Zynq UltraScale+ ZU4/ZU5/ZU7
Quad/Dual Cortex A53 @ 1.5GHz
Dual Cortex R5, ARM Mali 400 MP2
265, H.264 Video Codecs
ZU4, ZU5, ZU7 (CG/EG/EV) devices
Up to 504K Logic Cells
16 x FPGA transceivers @16.3Gbps
4 x PS transceivers @6Gbps
24 LVDS Pairs/48 SE IOs + 48 SE IOs
Memory:
2GB/4GB DDR4 for PS with ECC (Expandable)
1GB DDR4 for FPGA (Expandable)
8GB eMMC Flash
Form Factor: 95mm x 75mm
BSP Support: Linux 4.14.0
Temperature: Industrial Grade Operation
iWave Systems has the stock of various ZU4, ZU5, ZU7 MPSoC based SOMs and also provides the comprehensive development board for immediate evaluation.
Analog and mixed-signal semiconductor company MagnaChip Semiconductor (Cheongju-si, South Korea) has announced the release of a 100-V mid-voltage MOSFET with a new thermal package designed for the fast-growing electric bike (e-bike) market.
The MOSFET is housed in a M2PAK-7P package suitable to meet the particular requirements of electric bike (e-bike) systems, which are powered by electric motors running on lithium-ion batteries. The 100V MOSFET, says the company, features a best-in-class thermal package and is an essential electronic device that controls the speed of the motor and supplies a stable current of electric power to the lithium-ion Battery Management System (BMS).
“The emergence of e-bike is a highly attractive opportunity for MagnaChip,” says YJ Kim, CEO of MagnaChip. “Our 100V MOSFET product in a specially-designed thermal package is designed for the particular needs of motors and lithium-ion batteries that power e-bikes like electric scooters. MagnaChip plans to launch new Mid-Voltage MOSFET products with M2PAK-7P to meet the evolving needs of this rapidly-growing consumer sector.”
The company’s 100V mid-voltage MOSFET is said to be especially suitable for e-Bikes requiring high power systems. With its M2PAK-7P package, says the company, the new MOSFET achieves a best-in-class thermal performance and a lower Rds(on) compared to other MOSFET products currently on the market.
The device also increases the maximum operating current to 240 A. These features enable a high level of operational efficiency and a secure supply of power, both of which are necessary for high-powered e-bikes.
The company says it also plans to introduce 80- and 135-V mid-voltage MOSFET products in the M2PAK-7P package. With this strategy, says the company, it plans to aggressively expand its presence within the e-bike market and become an industry leader for all power products within it.
Connectivity continues to be one of the most important features of any device in recent times, even for devices that are not directly connected to the internet, the need to send data from one device to the other is an important part of the ubiquitous world being built today. For designers, DIY hobbyist, and professionals alike, the choice of selecting the right communication module depends on the knowledge of the available options, as such, for today’s tutorial, we will look at the use of Long Range 315MHz RF Wireless Transceivers as a communication option for your Arduino projects.
315 Mhz transceivers
Short-range RF Transceivers like the 433MHz transmitters discussed in one of our previous post are very popular among DIY hobbyist and makers, however, their short-range was a bottleneck for users as they barely offer signal coverage for an area bigger than a standard room. To solve this and give makers more option and value, PMD Way developed these new 315/415 Mhz transceivers.
The new transceivers work the same way as the cheaper modules, maintaining the same pin configuration/layout, support the same libraries (like the VirtualWire library for Arduino) but the new modules, however, have a greater power output and a solid, convenient PCB antenna which increases range while also keeping things neat. The attainable transmitting power of the modules depends on the voltage applied at it’s VCC pin. For instance, when VCC is 5v, the modules are able to reach 150m range in open space, as such, the range can be improved further by increasing the supply voltage.
Some of the specifications of the long-range RF Modules are highlighted below:
Transmitter working voltage: 4~12VDC
Transmitter working current: 40mA
Transmit power: 27dBm @ 12VDC
Working frequency: 315MHz
Transfer rate: 4.8kbps (max)
Transmission distance: When supply power is 5V, the open area transmission distance is around 150 meters. To increase transmit range, you can increase the power to the transmitted up to 12V DC.
Antenna: Onboard 315MHz dedicated PCB Antenna.
Receiver operating voltage: 2~5.5V DC
Receiver current: 2mA
Sensitivity: -110db
For today’s tutorial, we will demonstrate how to use these modules by creating a simple sketch to send messages between two Arduino fitted with these modules. The first Arduino board will serve as the transmitter using a pushbutton such that when the push button is pressed, it sends an on/off data via the long-range RF modules to the second Arduino which serving as the receiver, which will turn the LED connected to it on/off in accordance with the signal received.
Required Components
The following components are required to build this project;
An external power supply for one Arduino. This can be an AC-DC wall wart, USB power bank, 9V battery, any power source to power the transmitter.
Two Arduino boards are required because we will build a complete system with a transmitter and receiver. If you don’t have an Arduino Uno available feel free to use any Arduino compatible board.
Schematics
As mentioned during the introduction, we will essentially build two projects. One will serve as the transmitter while the other will serve as the receiver as such, we have two schematics. The image of the short-range RF modules will be used since the connection is the same and the Long-range RF modules do not have a fritzing package.
Transmitter Schematics
The transmitter schematics is quite simple, we only need to connect a push-button and the transmitter of the 315MHz transceiver to the Arduino as shown in the image below.
Transmitter Schematics
The pin-to-pin connection between the Arduino and the RF transmitter module is described below:
Arduino – RF Transmitter
5v - VCC
GND - GND
D12 - Data
Receiver Schematics
For the Receiver, we will connect a LED to the Arduino in addition to the Receiver of the 315MHz transceiver as shown in the image below.
Receiver Schematic
The pin-to-pin connection between the Arduino and the RF Receiver module is described below:
Arduino – RF Receiver
5v - VCC
GND - GND
D12 - Data
Go over the connections once more to ensure everything is as it should then proceed to the code section.
Code
The Code for this project is heavily dependent on the popular Virtual Wire Library. The library can be installed via the Arduino library manager or by downloading the library from the attached link and installing it by extracting it into the Arduino Libraries folder. The Virtualwire library comprises functions that allow us to perform actions like set the transmission power of the RF modules, encode the data, etc., generally reducing the amount of code we need to write to interact with the RF Modules.
With the library installed we can now proceed to write the code. Just like the schematics, we will write two sketches for this project; one for the transmitter and the other for the receiver.
Transmitter Sketch
We will start with the code for the transmitter. As mentioned during the introduction the sketch for the transmitter will simply send commands (a for ON, b for OFF) to the receiver when off.
We start as usual by importing the libraries that we will use, which in this case, is just the VirtualWire library.
// Transmitter
#include <VirtualWire.h>
Next, we create variables that will be used to hold different data like the characters to be sent by the transmitter, the buffer length, and the buffer name. We also declare the pin of the Arduino to which the push-button is connected.
With that done, we then proceed to the void setup() function. Here we invert the enable signal of the transmitter, use the vw_setup() function to specify the speed of communication in bps, use the vw_set_tx_pin() to specify the pins of the Arduino to which the transmitter pin is connected and finally, set the pin mode of the pin to which the push button is connected as input.
void setup()
{
vw_set_ptt_inverted(true); // Required for RF Link modules
vw_setup(300); // set data speed
vw_set_tx_pin(12);
pinMode(Button, INPUT);
}
With that done, we move into the void loop function, which is where the real action happens. The void loop function comprises of two if statements which check the state of the push-button. The vw_send() function is called to transmit the appropriate data based on the state of the push button.
void loop()
{
if (digitalRead(button)==HIGH)
{
vw_send((uint8_t *)on2, strlen(on2)); // send the data out to the world
vw_wait_tx(); // wait a moment
delay(200);
}
if (digitalRead(button)==LOW)
{
vw_send((uint8_t *)off2, strlen(off2));
vw_wait_tx();
delay(200);
}
}
The complete code for the transmitter is available below and also attached under the download section of the tutorial.
// transmitter sketch
#include <VirtualWire.h>
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;
const char *on2 = "a";
const char *off2 = "b";
int button = 8;
void setup()
{
vw_set_ptt_inverted(true); // Required for RF Link modules
vw_setup(300); // set data speed
vw_set_tx_pin(12);
pinMode(Button, INPUT);
}
void loop()
{
if (digitalRead(button)==HIGH)
{
vw_send((uint8_t *)on2, strlen(on2)); // send the data out to the world
vw_wait_tx(); // wait a moment
delay(200);
}
if (digitalRead(button)==LOW)
{
vw_send((uint8_t *)off2, strlen(off2));
vw_wait_tx();
delay(200);
}
}
Next is the Receiver Sketch.
Receiver Sketch
The sketch for the receiver is quite straightforward. When data is received from the transmitter, the receiver processes the data and issue commands turns the LED ON or OFF depending on the command that was received.
We start the sketch as usual, by including the library that will be used, which is still the same virtual wire library used for the transmitter sketch. Next, we create variables buf and buflen that will be used to store the data received from the transmitter along with its length and also declare the pin of the Arduino to which the LED is connected.
With that done, we write the void setup() function.
We start the function by inverting the state of the enable pin, set the communication speed to 300bps to match that of the transmitter, set the rx pin as D11, start the receiver -> set it to listen for incoming traffic, and then specify the mode of the pin to which the LED is connected.
void setup()
{
vw_set_ptt_inverted(true); // Required for RF link modules
vw_setup(300);
vw_set_rx_pin(11);
vw_rx_start();
pinMode(ledpin, OUTPUT);
}
up next is the void loop() function.
The void loop() function is quite straight forward. We check if data was received into the buffer by calling the vw_get_message function. If data was received, a select case statement is then used to compare the data that was received. If “a” was received, the LED is turned ON and if “b” was received, the LED is turned OFF.
void loop()
{
if (vw_get_message(buf, &buflen))
{
switch(buf[0])
{
case 'a':
digitalWrite(ledpin, HIGH);
break;
case 'b':
digitalWrite(ledpin, LOW);
break;
}
}
}
That’s it! The complete code for the receiver is below and also attached under the download section of the project.
// receiver sketch
#include <VirtualWire.h>
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;
int ledpin = 2;
void setup()
{
vw_set_ptt_inverted(true); // Required for RF link modules
vw_setup(300);
vw_set_rx_pin(11);
vw_rx_start();
pinMode(ledpin, OUTPUT);
}
void loop()
{
if (vw_get_message(buf, &buflen))
{
switch(buf[0])
{
case 'a':
digitalWrite(ledpin, HIGH);
break;
case 'b':
digitalWrite(ledpin, LOW);
break;
}
}
}
Demo
Go over the connections once again to ensure all is correct then connect both devices to the computer and upload the sketch one after the other.
With the sketches uploaded, power both devices and press the push-button on the transmitter. You should see the LED connected to the receiver light up.
Demo
The long-range RF modules provide an alternative way to implement cheap communication over somewhat large distances as such, it is worth considering for your low-budget, local network of devices project.
That’s it for today’s project. Feel free to ask any questions you might have about this via the comment section.
A video of the project in action can be found on youtube.
Geniatech and Linaro announced a “SOM 3399” module that adopts the 96Boards SOM spec and runs Linux on a Rockchip RK3399. There’s also a “CBD96-3399” carrier for the module.
Linaro Ltd, the open source collaborative engineering organization developing software for the Arm® ecosystem, and 96Boards Manufacturing Partner Geniatech today announced the launch of another Rockchip RK3399 Board and Carrier Board.
The module adopts the 96Board Computing SOM specification launched in April 2019. The SOM specification is based on a standard form factor and is compatible across SoCs. This means more choice and flexibility for developers, who can seamlessly plug and play between a range of different SOM solutions. The launch of the RK3399 provides yet another SOM solution, delivering low power consumption and high efficiency, with a CPU frequency up to 1.8 GHZ and excellent image processing ability. The RK3399 SOM can also be combined with the carrier board to form a complete industrial application motherboard, which can be applied in various embedded Internet of Things fields.
CBD96-3399 Rockchip RK3399 Carrier Board
The SOM 3399 includes the following features:
6-Core CPU provides high-speed processing capability
High performance Dual-core Arm Cortex-A72 MPCore and Quad-core Arm Cortex-A53MPCore processors. Big cluster with dual-core Cortex-A72 is optimized for high performance and little cluster with quad-core Cortex-A53 is optimized for low power.
3D Graphics Engine:ARM® Mali-T860 MP4 Quad-core GPU Support OpenGL ES1.1/2.0/3.0 and OpenCL 1.2, DirectX11.1. Supports AFBCEmbedded 4 shader cores with shared hierarchical tiler.
4Kx2K up to 60fpsHD Resolution
Supports 4Kx2K (VP9H.265/HEVC/H.264/AVC), 1080P @ 60fps multi-format video decoding (MPEG-1,MPEG-2,MPEG-4,VC-1),and video encoder for H.264 up to HP@level 4.1, MVC and VP8. Multiple video input and output interfaces
2 MIPI-DSI input interfaces with two ISP image processors, and Embed two VOPs. Supports dual-screen simultaneous/dual-screen display.
Ultra-high integration – ultra-small size
The core board integrates RK3399, CPU DDR, eMMC, a power management module, and Ethernet PHY chip. It has high integration, which greatly reduces the design difficulty of the application backplane and helps enterprises to quickly develop mass production specific application products.
Specifications listed for the CBD96-3399 carrier with SOM 3399 module include:
Processor (via SOM 3399) — Rockchip RK3399 (2x Cortex-A72 cores @ up to 1.8GHz, 4x Cortex-A53 cores at up to 1.4GHz); 28nm fab; Mali-T860 GPU
Memory/storage:
2GB (or optional 4GB) LPDDR4 RAM (via SOM 3399)
8GB (or optional 16/32/64GB) eMMC (via SOM 3399)
MicroSD slot
Networking:
Gigabit Ethernet port
802.11b/g/n/ac (2.4GHz/5GHz) with Bluetooth 4.2
GPS
Other I/O:
HDMI port for up to 4K UHD H265/H264/VP9 or 3x 1080p@30fps
No pricing or availability information was provided for the SOM 3399 and CBD96-3399. More information may be found in Linaro’s announcement and Geniatech’s SOM 3399 and CBD96-3399 product pages. More details should eventually appear on Linaro’s 96Boards SOM page.
A while back in May 2018 at the Maker Faire Bay Area, Arduino after a long year of legal battles announced the launch of two boards which were the MKR Vidor 4000 and the Arduino Uno WiFi Rev 2 which was designed to come up as a somewhat replacement for the legendary Arduino Uno.
This was at a time when several development boards like the ESP32 and NodeMCU which was WiFi enabled were becoming the darling of the maker community as such it quite made sense for Arduino to launch something similar for the beloved Arduino Uno.
The Arduino Uno WiFi Rev2 is basically an Arduino Uno Rev3 with more kick. Unlike the Arduino Uno, it is based on the ATmega4809 which is a microcontroller featuring the 8-bit AVR® processor with hardware multiplier – running at up to 20MHz and with up to 48 KB Flash, 6 KB SRAM and 256 bytes of EEPROM in 48-pin package. The Uno WiFi Rev2 was the first AVR device to feature Microchip’s Core Independent Peripherals (CIP) and it is one of the key features that make the Uno WiFi a bigger deal than it appears on the surface.
Asides from running on a different processor, the Uno WiFi Rev2 is beyond the Arduino Uno on so many levels as the board comes with more RAM (6KB) and Flash memory (48KB), three hardware UARTS allowing communication which means at least 3 serial devices can be connected, and 6 integrated high-speed Analog-to-Digital Converter (ADC). To show how high up the Uno WiFi is compared to the Uno, it also comes with a Microchip ATECC608A cryptographic co-processor which provides hardware-based security and hardware-based key storage which are super useful when connecting your projects to the cloud.
To compete with other WiFi boards dominating the Maker Market, the Chief feature for Uno WiFi is probably the WiFi Support as it comes with the NINA-W102 which is the same ESP32-based U-Blox WiFI module used by the new MKR WiFi 1010 announced during the Last Arduino Day.
It is important to note that the Uno WiFi Rev2 is quite different from the Arduino Uno WiFi which was essentially an Arduino Uno with an ESP8266 WiFi module slapped on it but it has since been retired and is no longer being produced.
The Arduino Uno WiFi Rev 2 is currently available for purchase from the Arduino Store.