Monthly Archives: March 2018

What is E-Smog and How to Detect it?

Many people claim advancement in technology and the proliferation of electronic devices is creating a sea of electromagnetic waves around us, and this eSmog is actually a cause for many of the illnesses we are afflicted with nowadays. While eSmog causing bad health is up for debate, some people seem to be more sensitive to it than others are. However, the presence of electromagnetic waves around us cannot be ruled out, with greater concentrations around devices such as computers, mobile phones, Wi-Fi routers, cordless phone bases, and in fact, anything electronic and powered up. Therefore, an instrument that measures the level of electromagnetic fields around it is in order.

Today, it is practically impossible for us to live life without our electronic devices and everyday technology that produce electromagnetic fields. Although we cannot see the electromagnetic fields that surround us, an instrument that can measure its presence is useful for us to know, say, whether a brick wall has reduced the level, and to what extent.

We all need our Wi-Fi, Zigbee, Bluetooth, television, radio, mobile phones, and other gadgets. To know the level of eSmog each of them is producing, you can use the kit TAPIR—an eSmog detector. You can assemble this tiny instrument from the seven small PCBs in the kit. TAPIR comes with an antenna and two types of electromagnetic detectors.

The kit has a PCB panel, actually made of seven parts. You can assemble the PCBs and make them form the enclosure for TAPIR. The PCBs are numbered—starting with the top piece, the left sidepiece with a switch, the bottom piece with the components, the right side piece with the headset connector, the negative battery connection piece, the positive battery connection piece, and the end piece. A headset plugged into the connector allows the user to hear the device detecting eSmog. The intensity of sound increases with the level of eSmog TAPIR detects. You need a single AAA battery to power the kit.

TAPIR—acronym for Totally Archaic but Practical Interceptor of Radiation—is a wideband ultrasensitive eSmog detector. Once you have connected it to the antenna and the headphones, and switched it on, you can move it around an electronic device. This allows you to hear different noises depending on the type and frequency of the field the device is emitting.

Making the two antennae for the TAPIR is important for it to function properly. All around us, there are two types of electromagnetic fields—the E-field or electrical field, and the H-field or the magnetic field—and two separate antennae are necessary to allow TAPIR to detect the two fields.

The E-field antenna consists of a length of solid insulated wire. The kit includes the wire, and you will need only half of it to form the antenna. Insulate one end of the wire with heat-shrink tubing and bend it to form a loop. At the other end of the wire, solder the cinch connector shell to complete the antenna.

A coil is enclosed with the kit, and you can solder this coil to two pieces of insulated wires. Solder the free ends of the wires to the second cinch connector, and your H-field antenna is ready.

Accurate Power Monitoring with LTC2992

Linear Technology Corporation, now a part of Analog Devices, Inc., has recently placed on the market a power monitoring IC, LTC2992, which offers a wide-range, dual monitoring system for current, voltage, and power for 0-100 VDC rails. The IC is self-contained and does not need additional circuitry for functioning.

Users get a variety of options for operating the LTC2992. For instance, they can derive power from a 3-100 VDC monitored supply, or from a 2.7-100 VDC secondary supply, or from the shunt regulator on-board. Therefore, when monitoring the 0-100 VDC rail, the designer does not have to provide a separate buck regulator, a shunt regulator, or an inefficient resistive divider.

Within the LTC2992 are a multiplier and three Analog to Digital Converters (ADCs) of the delta-sigma type. Two of the ADCs provide measurements for current in each supply, while the third ADC measures voltage in 8- or 12-bit resolution and power in 24-bit resolution. The wide operating range of the LTC2992 makes it an ideal IC for several applications such as blade servers, advanced mezzanine cards, and 48 V telecom equipment.

Users with equipment using negative supply or supply greater than 100 VDC can make use of the onboard shunt regulator. The LTC2992 has registers that one can access with the I2C bus, and it uses these registers to store the measured values. It can measure current and voltage on-demand or continuously, using these to calculate the power, and stores this information along with maximum and minimum values in the registers.

The LTC2992 has four GPIO pins, which the user can configure as ADC inputs for measuring neighboring auxiliary voltages. Over its entire temperature range, the LTC2992 takes measurements with only ±0.3% of the Total Unadjusted Error (TUE). For any parameter going beyond the thresholds programmed by the user, the LTC2992 raises an alert flag in the specified register and on the specified pin. This is according to the alert response protocol of the SMBus.

The I2C bus on the LTC2992 operates at 400 kHz and features nine device addresses, a reset timer for a stuck bus, and a split SDA pin for simplifying the opto-isolation for the I2C. Another version of the IC, the LTC2992-1 offers users an inverted data output pin for the I2C. This makes it easy for the users to interface the IC where the opto-isolator has an inverting configuration.

The ICs, LTC2992 and LTC2992-1, are both available in automotive, industrial, and commercial versions. Their operating temperature ranges are -40°C to 125°C for automotive, -40°C to 85°C for industrial, and 0°C to 70°C for commercial applications. Linear Technology Corporation makes both versions of the IC in packages of 16-lead MSOP and 16-lead 4 x 3 mm DFN, and both versions are RoHS-compliant.

Most electronic applications require monitoring of current, voltage, and power at board level. Knowing the key system parameters provides valuable feedback, allowing users to monitor the health of their systems and make intelligent decisions. They help in determining whether a system is operating properly, efficiently, or even dangerously. Users can choose for various types of monitoring ICs, ranging from hot-swap dedicated power ICs to temperature monitors.

It is Time for Chip Speakers

So far, speakers have been electromechanical devices, with a coil moving within a magnetic core, attached to a baffle or driver to move the air for producing the sound. With devices going down in size, manufacturers have been facing difficulties in producing electromechanical speakers in smaller sizes. Piezoelectric speakers are available, but they operate on a very narrow bandwidth.

Now USound GmBH, from Graz, Austria, has presented an audio speaker based on micro-electro-mechanical-system (MEMS) technology. This chip-sized speaker is suitable for small equipment such as Internet of Things (IoT) devices, wearables, smartphones, and earbuds.

By the end of the current year, USound expect to reveal Megaclite, a reference design using its MEMS speaker, Ganymede. So far, USound has fitted Ganymede to sunglasses at the high end. According to USound, Ganymede is suitable for mobiles, earbuds, and high fidelity, multidriver speakers playing above ear levels.

According to Mark Laich, senior adviser for business development at USound, making the diminutive MEMS drivers sound good across the audible spectrum was a huge challenge for the engineers. The major difficulty they faced was from the sound related physics, as it dictates the diaphragm size to push the air to be proportional to the wavelength of the sound emitted. That is why high-fidelity speaker systems use 12- to 15-inch drivers for producing low frequency bass sounds, 3- to 6-inch midrange drivers for the mid-frequency sounds, and 1 or less than 1-inch tweeter speakers for producing high-frequency sounds.

For the tiny speakers used in wearables, the size of the driver has to be some small portion of the wavelength of the sound it emits. Usually, some electronic or mechanical frequency equalization is necessary to make them sound high fidelity. Highest fidelity, as some headphones at the high end provide, is achievable only with multiple drivers. Typically, most of the reasonably priced earbuds have to sacrifice fidelity as they use a single driver, while adding electronic equalization to sound better.

As it is not possible to circumvent the sound related physics, MEMS speakers from USound are similar. Their low-end model has a single driver along with electronic equalization within a chip-scale package, and this bonds directly to the MEMs die. The MEMS frame is actually a longish actuator that moves a diaphragm using suspension beams made of piezoelectric material. The surrounding diaphragm also seals the entire chamber.

According to Laich, this arrangement achieves high-speed actuation, with a response time in microseconds. The company says this will help in noise cancellation in models to come, when they build them with a MEMS codec partner. At present, the air-pushing cone or diaphragm lies at the bottom side of a cavity, with thin piezoelectric drivers suspending it by the corners. The drivers supply the necessary energy to move the diaphragm in synchronization with the audio signal.

Listeners describe the sound from the MEMS speakers as digital, similar to the sound from a CD in comparison to that from a vinyl record. Of course, even when fortified with electronic equalization boosting the low frequencies, the sound from a single driver design does not match the high fidelity demonstrated by multidriver design.

Pro-HAT & GPIO-Zero for the Raspberry Pi

HATs or Hardware Attached on Top are very popular with the Raspberry Pi (RBPi) community. They plug on to the GPIO pins on the RBPi, providing additional functionality to the single board computer. The Pro-HAT puts the GPIO ports of an RBPi in numerical order, and labels them clearly. The user gets a female socket for each port into which, they can plug their wires or component leads.

Pro-HAT is actually a 72-point breadboard with the arranged GPIO ports and includes plenty of power and GND sockets, which every experimenter looks for when playing with some electronics. For instance, when plugging in LEDs, one does not need any current-limiting resistors, since these are already built-in.

Pro-HAT provides a protection circuit on each GPIO port. This protects the GPIO ports from any incorrect wiring, which happens during experimentation. However, you must still be careful not to short the 3V3 or 5 V pins directly to GND, as this can do serious damage.

However, it is still possible to bypass the 330 Ohm resistors on the Pro-HAT board. The board has an unprotected side where the ports are available as through-holes, without protection. This is especially useful for buzzers, which usually require more than the 10 mA current limit to operate than the resistors impose.

Created by Dave Jones and Ben Nuttal, the GPIO-Zero is the ideal way to start with Python GPIO programming. The user finds it very simple, as there is nothing to install when using it to start with the Pro-HAT. The GPIO-Zero kit has plenty of components, making it realistic for individuals and schools in discovering the joys of controlling the world with the RBPi, the Pro-HAT, and the GPIO-Zero kit.

The GPIO-Zero kit contains an MCP3008 ADC Chip, a TMP-36 analog temperature sensor, a single-channel relay, a PIR motion sensor, five 10 mm LEDs, a 10 K potentiometer, a 40-way male header, a large button, a 10 k resistor, 20 male-to-male jumper leads, and 20 male-to-female jumper leads.

The Pro-HAT protects ports by using a 330 Ohm resistor in series with each port, which does not allow currents over 10 mA into or out of the port. There is also a 3V3 Zener diode on the port, which saves the port from any overvoltage. Further, GPIO pins 2, 3, and 26 have hardware pull-ups, which means each of these pins are pulled up to 3V3 by resistors or 2 k value. This makes the default state of these pins to remain high, until an external signal pulls them low. Likewise, GPIO pins 2 & 3, which are also the I2C ports, are pulled down to zero volts through resistors of 2 k value. This keeps these pins grounded, but an external signal can pull them high.

Pulling the pins high and low through resistors on the Pro-HAT works well for experiments the GPIO-Zero kit allows. However, the resistors and the protection circuitry may not work well with high-speed SPI devices, such as the PiTFT and other small SPI LED color screens. In such cases, simply unplugging the Pro-HAT will solve the problem.

What is ReRAM?

DRAM is a popular memory technology regularly in use in almost all computers and smartphones today. However, resistive RAM or ReRAM is an upcoming parallel technology of high-density storage class memory, whose performance, researchers claim, has now reached very close to that of DRAM.

According to 4DS Memory Limited, who patented their Interface Switching ReRAM, have made substantial changes to the architecture of their product. They claim this has resulted in substantially improving read access so that the speed of ReRAM is now comparable to that of DRAMs. According to Guido Arnout, company CEO and Managing Director, the development has presented the company with several opportunities.

So far, most memory technologies have faced inherently high errors of bit rates. This includes ReRAMs as well, with randomly large cell current fluctuations to blame. Although manufacturers do include techniques for error correction to retrieve data reliably, the activity is time consuming and affects read access times negatively and cripples read speed.

After making the changes, 4DS could not find any large fluctuations with their Interface Switching ReRAM even with an extensive study. They claim this indicates the memory needs minimal error correction. Therefore, the high-density storage class memory how has effective read speeds comparable to that of DRAM. According to Arnout, the company has also scaled their memory products to 40 nm, with a significant increase in endurance.

Initially, 4DS was trying to create a storage class memory to compete with NAND flash. However, with prices of NAND flash dipping fast, the opportunity for ReRAM is now stationed between DRAM and flash. With the difference in price between DRAM and flash growing regularly, the opportunities for 4DS are also getting larger.

4DS uses a different approach for developing their Interface Switching ReRAMs. Rather than use the regular filamentary technology, 4DS uses a technique that allows cell currents to scale with geometry. According to 4DS, they use smaller cells that yield lower cell currents, and these currents can flow more reliably through narrow on-chip wires, which are necessary for achieving higher densities. However, lower cell currents also means the memory suffers longer latency, and 4DS, through extensive measurements and analysis, had to optimize the cell currents so that the latency matched that of DRAM in a high-density storage class memory.

Even short cell latency is not adequate. In reality, latency is actually made up of the sum of the inherent memory latency added to the time required to detect and correct any read errors.

The Interface Switching technology from 4DS reduces the switching region from the influence of random irregularities. That makes the latency of the new Interface Switching ReRAM the dominant factor rather than the overhead of its error correction.

SanDisk had predicted a decade earlier that ReRAM would eventually replace the NAND flash. Now, with the Interface Switching ReRAM, 4DS is looking at a tier of storage class memory that will enable data centers to deliver more content on the Internet at a faster rate and efficiency. After proving the concept of its Interface Switching ReRAM, 4DS is now focusing on scaling it for achieving decent yields.

A Rain Alert for the Raspberry Pi

This Raspberry Pi (RBPi) rain alert will let you know when it starts to rain, so you can reel in the clothes you had let out to dry after washing. Although the kit uses an RBPi3, any model of the RBPi family can easily handle this project. A later extension can make it send tweets as well, but for now, it simply triggers a buzzer.

The primary sensor in this project senses falling raindrops. This raindrop sensor is actually a printed circuit board with two traces running across the entire board in an inter-meshed dual comb pattern. As the two sets of teeth of the comb traces remain separated by about a millimeter, they show high resistance when dry. Their resistance decreases when a drop of water falls across the traces, shorting them.

A sensor controller tracks the resistance between the traces, the resistance reducing as more drops of water fall on the sensor. A potentiometer on the controller allows the user to adjust the level of detection when the normally high digital out pin will go low. When the sensor detects rain, it changes the status of the pin. The RBPi, monitoring the status, sets off the buzzer.

Since it is essential to detect the start of rainfall, setting the potentiometer to trigger when a couple of raindrops have fallen on the sensor is adequate. Adjusting it is easy, which you can do when you have two or three raindrops collected on the sensor. Turn the potentiometer until the buzzer just stops, and turn back until you hear it going again.

Since it has to detect raindrops, placing the sensor such that it is always under an open sky is important. However, as electronics and rain do not work satisfactorily together, it is very important the rest of the circuitry remains protected from rain. The best way to achieve this is to have the RBPi and rest of the electronics inside a waterproof plastic case, with only the raindrop sensor hanging out. Run the Python program here and wait for the beeps to inform you everything is working properly.

Apart from the raindrop sensor and its control board, you need only a few other parts to get the kit working. A few jumper wires, an active piezo buzzer, and a mini breadboard are all you need. You can start by connecting the output of the control board to the GPIO18 port of the RBPi to read its status, and set off the buzzer from the RBPi’s GPIO13 port, while the sensor detects raindrops.

If you do not like sounding a buzzer, you can activate some LEDs instead when it rains. Else, program the RBPi to send an email, an sms, a push notification, or tweets a photo warning when it detects rain. Since the continuous sounding of the buzzer will become tiring after a while, you can tweak the code to stop it after a while.

Since the sensor is out in the open, you will have to run out and wipe it dry as soon as it stops raining, to prepare it for detecting the next shower.

Motion Tracking through the MC3672

This year, the MSEC or MEMS & Sensors Executive Congress had mCube exhibiting their incredibly small and low-power MC3672, an inertial sensor product. This is a three-axis accelerometer, and its size is only 1.1 x 1.3 mm. This tiny WLCSP packaged device is a low parasitic unit, with enormous possibilities of unobtrusive use as low power motion tracking in wearable design, and in a completely new set of applications in future.

Recently, mCube acquired Xsens and they were able to couple a sensor fusion software to their tiny accelerometer. This gave them the ability to sense body motion and capture solutions for health, entertainment, and fitness. The combination also allows them to control and stabilize inertial measurement units in industrial applications.

Almost all are aware of MEMS motion sensors, as tablets, smartphones, and wearables use them popularly. Use of the MC3672 accelerometer will generate more applications for these devices in the future. This could include new areas such as in the medical world, related to prevention and diagnostics of illness. For instance, when visually inspecting the throat, stomach, or intestines of a patient, physicians often need to perform invasive and unpleasant procedures.

In future, patients would be able to swallow a camera-pill that can wirelessly beam images from the inside of the body to a display for the physician to view. Miniature motion sensing incorporated within the camera-pill could allow medical practitioners to navigate the pill effectively by actuating and controlling it. This would allow them to monitor its location and orientation in real-time as it passed through the body. Images captured by the camera would enable precise diagnosis and investigation of any problems.

According to Dr. Sanjay Bhandari, Senior VP of mCube, a plethora of new applications will come into life based on the granular, precise measurement of motion, orientation, tilt, and heading of the sensor. For instance, some applications will be able to capture motion data to communicate it to cloud software services, and ultimately sharing it with networked systems for monitoring and analysis.

Achieving most of the envisaged applications is only possible with motion-sensing systems that are extremely small and drain very little power from an arrangement of energy harvesting or a battery.

Along with the low power consumption and small system size, all components in the system must adhere to the design features. The sensor interface uses Silicon and CMOS-based circuits that filter, amplify, and fit the analog to digital processors to work its magic.

The monolithic, single-chip design by mCube integrates both the CMOS and the MEMS within a clever extension using a standard CMOS-base process. This is a reliable procedure for handling high volumes and produces excellent yields. Within the chip, mCube has interconnected the MEMS and the CMOS very efficiently.

In future, mCube plans to integrate BLE or Bluetooth Low Energy into the MCU in its SIP package—they want to realize IoMT-on-a-Chip. They have protected their technology by 100 approved patents.

The acquisition of Xsens brought to mCube the 3D technology to track motion in the sensor world—a high-precision module for sensing motion in 9 degrees of freedom.

Oscilloscopes Lose their Faces

The word oscilloscope usually conjures up images of a box with a display. Earlier, oscilloscopes were bulky devices with a display made of a cathode ray tube, but later the models became sleeker, and came with a liquid crystal display. Another difference was in their method of measurement. Whereas there were analog units earlier, later models sported an analog to digital converter inside, which converted all analog signals to digital data. Nevertheless, the display continued to be a part of the oscilloscope.

However, Tektronix now has unveiled a low-profile oscilloscope that has lost its face—the display. The MSO5 series of oscilloscopes from Tektronix has a faceless version aimed at Automated Test Equipment (ATE) applications. It is a low-profile version competing with modular oscilloscopes and digitizers.

Suitable for automated tests or for monitoring machines, the low-profile MSO58 of the MSO5 series, is a rack mountable unit. All its specifications match those of its regular benchtop cousins. It has eight analog inputs with FlexChannel features, which allow eight digital channels to substitute the analog channel with a 1-GHz bandwidth on all of them. The real-time scan rate for all the channels is 6.25 Gsamples/sec with 12-bit ADCs on each channel, but a high-resolution mode allows the resolution to increase to 16 bits and 125 Msamples/sec. That makes the effective number of bits as 7.6 at 1 GHz, or 8.9 at 20 MHz, with a record length of 125 Msamples/channel.

Software within the faceless oscilloscope can help with jitter and serial bus analysis, channel math and Fast Fourier Transformations (FFT). For bench and debugging applications, the software also provides cursors. There are six USB host inputs, on USB input for a device, a LAN port, a Display Port, DVI-D port, SVGA output port. However, the device lacks GPIB connectivity.

As the internal hardware and functionality is identical in both the benchtop and the faceless versions of the MSO5 series oscilloscopes, any automation code for production for device validation and characterization works interchangeably. The six USB host ports may lead one to believe the low-profile oscilloscope could be useful as a system controller. However, the operating system of the unit is a closed Linux version, and a separate PC is necessary for automated use.

The six USB device ports can help in creating a network, to which, one can add more accessories such as an external storage or other instruments. If you have additional MSO5 low-profile units to work together, you can also add a USB hub or an Ethernet switch. Unfortunately, for those using GPIB primarily, these units do not come with a GPIB port.

It is very easy to configure any input of the low-profile faceless oscilloscope as one analog or 16 logic channels. Therefore, one can mix and match the configuration to change it as necessary. For instance, channels 1 and 2 can be analog, while the channel 3 caters to 16 logic inputs.

Bandwidths for the MSO5 series oscilloscopes are 350 MHz, 500 MHz, 1GHz, and 2 GHz. However, one can upgrade any model at any time to operate at any bandwidth.

Using Hall-Effect Type Sensors Effectively

We are familiar with appliances such as wine coolers, freezers, and refrigerators. They keep out beverages and food cold, extending their useful life. Most often, these appliances have lights that illuminate the insides when the user opens their doors. Since the lights only need to be on when the user opens the door, usually, the designer of such appliances place a sensor to detect the opening and closing of the door.

A sensor of the Hall-effect type can detect the position of the door. In refrigerators, the position of the sensor is within the frame, while a permanent magnet is placed on the door directly opposite the Hall-effect type sensor. For refrigerators with multiple doors, each door needs a magnet and for the detection, each magnet must have a corresponding sensor placed in the frame. The adjustment of proximity of each Hall-effect type sensor and magnet pair is such that the Hall-effect type sensor detects the magnet only as the door closes completely.

An electronic control unit inside the electronics assembly of the refrigerator monitors the output from the Hall-effect type sensors and turns the lights on or off as necessary. Hall-effect type sensors can detect a variety of proximity- and position-sensing applications such as when there is a need to discover the proximity of a moving part relative to a sensor placed in a fixed location.

For instance, Hall-effect type sensors can help to stop the motor opening or closing a garage door once the door has reached its desired position. Typically, this needs a system of two Hall-effect type sensors to detect the two dominant positions of the door—open or closed. Each sensor also needs a corresponding magnet to trigger it.

The position of one of the magnets on the drive chain of the garage door opener places it directly next to the sensor that detects a closed door. The position of the other magnet, also on the drive chain, is such that the drive chain brings it next to the other Hall-effect type sensor as the door opens completely.

Hall-effect type sensors are preferable to other sensors such as reed relays, as the former has no moving electrical contacts, resulting in long life and improved reliability. Other applications that use Hall-effect type sensors effectively are vending machines, security locks on doors, vacuum cleaners, washing machines, dishwashers, and similar applications requiring door- and lid-position sensing.

A flow switch is another application that benefits from the use of a Hall-effect type sensor, which detects the motion of a piston, paddle wheel, or a valve fitted with a permanent magnet. For instance, this arrangement suits tankless water heater units, where the flow sensor has a permanent magnet fixed to a piston. The increasing presence of water pressure in the system moves the piston and its associated magnet near to a permanently positioned Hall-effect type sensor. This causes the output of the Hall-effect type sensor to change and it signals the presence of flowing water.

Similarly, a turbine can have a magnet attached to its blades. As the blades rotate, the magnet passes by a fixed Hall-effect type sensor. The speed at which the blades rotate is proportional to the fluid flowing through the turbine.

A Bench-Top Reflow Soldering Machine

You can easily solder a board with leaded components if you have a hand held soldering iron. Another method of soldering several leaded components in a short time is to pass the board through a wave soldering machine. However, component manufacturers are moving away from leaded components to making more of leadless components, and the soldering technology has had to follow through.

Soldering leadless components or surface mount components requires a different technique than solder wire and soldering iron. Usually, this needs a reflow oven. The process of soldering surface mount components involves applying solder paste to the pads on the board, carefully placing the components in their designated places on the solder paste, and passing the mounted boards through a reflow soldering machine.

Using surface mount technology has its own advantages over the use of through-hole components. Apart from the several electrical, mechanical, cost, and size benefits of using surface mount components, the use of a reflow machine for soldering the whole board within about three minutes is enough reason for switching over totally to surface mount technology.

Selecting a bench-top reflow soldering machine requires looking at different aspects. A practical wide drawer type design makes it easy to load and unload boards. A large window on the side should allow you to see inside the machine when soldering. Modern reflow machines usually feature digital controls along with a touch controlled display panel. Some even offer a USB port allowing you to connect to a computer for a more detailed control.

Reflow soldering machines are available in different sizes, the larger ones allowing a large enough surface to solder several boards at a time. However, larger surfaces are only useful if the machine can distribute the heat evenly over it, since you would like to have all the boards soldered properly, and not just the ones in the middle. This is true for large boards also, and an even heat distribution helps to solder all the parts in the same way.

For evenly distributing the heat, reflow soldering machines use full-width quartz infrared lamps, followed up with an air circulation system. They are set up in a special way to enable a minimum temperature difference over the soldering area. Most manufacturers of soldering machines include PCB holders with brackets that do not influence board heating.

An important factor influencing soldering of surface mount components is the thermal profile. As the board passes through different regions of the reflow machine, it must gradually heat up to the proper temperature to enable soldering, and subsequently, cool down at a defined rate. As the board remains within the machine for only a definite time, the temperature variation over time defines its thermal profile.

Most modern reflow soldering machines are computer controlled and allow creation of elaborate thermal profiles by adjusting the speed at which the board traverses the entire length of the machine and the temperatures of different zones during its journey. Users can define up to three preheating zones, a reflow peak, and a cooling down phase. You can also store a few profiles so the machine can be operated in a stand-alone manner.