Sequential Timer for DC Motor Control

Most industrial processes require rotation of the motors in forward and reverse directions for desired periods. One good example is the automated bottle filling plant. Here the bottles move on a conveyor belt. When the bottles come under the filler, the filler comes down and fills the bottle, then it goes up and stops until the next bottle arrives.

A good domestic application is in washing machines. Once the timer is set to wash clothes, the motor automatically rotates forward and then backward for fixed periods 10 to 15 seconds with small pauses in between.

This is a sequential process, a sequential timer can be used to implement it. Sequential timer is a widely used circuit in industrial plants because most industrial processes are chain reaction type. That means as one process ends, it triggers the next. The ending of the last process triggers the first process.

Such sequence timers are micro controller-based, multi functional and programmable. But a very simple sequential timer can be developed using NE555 IC wired in mono stable mode. Cascading a number of these mono stable stages forms a sequential timer. The output of one stage is applied as the trigger to the next stage. So when the output of a stage drops, it triggers the next stage and the output of the next stage goes high, and likewise the chain reaction starts. Because here the process involves four steps forward→stop→reverse→stop,

four stages of NE555 ICs connected in mono stable multi-vibrator mode are used to form a four-stage sequential timer. The first stage rotates the motor forward. The second stage stops the motor. The third stage rotates the motor in reverse. The fourth stage stops the motor.

The block diagram of the sequential timer for DC motor control. The system consists of four blocks of NE555 timer ICs connected in mono stable mode. The output of each stage is connected to the trigger input of the next stage. The output of the first stage drives single-changeover relay RL1 and the output of the third stage drives relays RL2 and RL3 simultaneously. The second and fourth stages provide delay in between the first stage and third stage outputs.

The LEDs connected at the four stages indicate the status of the motor:

1. In the first stage, the green LED indicates that the motor is running forward.
2. In the second stage, the red LED indicates that the motor has stopped.
3. In the third stage, the blue LED indicates that the motor is running in reverse direction.
4. In the fourth stage, the red LED indicates that the motor has stopped.

The trigger input to the first stage is actually given through process start switch. The output of the fourth stage is fed back to the trigger input of the first stage through the SPDT switch. It decides whether the process continues in loop or one-time only.

Relay connections to the motor are made such that these provide reversible supply to the motor to rotate it forward and backward. As mentioned before, there are two single-changeover relays and one double-changeover relay. 

Circuit description

The circuit of the sequential timer. The first stage of the sequential timer is built around NE555 IC . IC1 is wired in mono-stable mode and its time period is determined by resistor R1, preset VR1 and capacitor C1. Preset VR1 is used to set the time from 4 to 45 minutes. This means you can rotate the motor from a minimum of 4 minutes to the maximum of 45 minutes. Maximum and minimum time limits can be changed by changing the values of the timing components as per the requirement.

Trigger pin of IC1 is pulled high with resistor R2. When switch S1 is pressed, it goes low and output pin 3 becomes high. The output of IC1 drives transistor T1 into saturation and relay RL1 energies. Also, LED1 connected with output pin 3 glows to indicate that the motor is running direction.

The output of IC1 is fed to the second stage through coupling capacitor C2. IC2 triggers when the output of IC1 goes low. Diode D1 acts as a free-wheeling diode. The second stage of the sequential timer is made around IC2. This stage provides delay between the first stage and third stage. The red LED connected at the output of IC2 indicates that the motor is in stopped condition.

IC2 too is configured in monostable mode. Its time period is determined by resistor R6, preset VR2 and capacitor C3. Preset VR2 is used to set the time from 1.75 to 10 minutes. If the process requires different timing, the values of timing components can be changed accordingly. The output of IC2 is coupled to the third stage through coupling capacitor C4. IC3 triggers when the output of IC2 goes low.

PCB and Component Layout

The third stage of the sequential timer is built around IC3. The timing component values of the third stage are the same as for the first stage because forward rotation time and reverse rotation time should be the same. The only difference is that this stage drives relays RL2 and RL3 simultaneously. Both the relays are connected in parallel and driven by transistor T2. LED3 connected at the output indicates change in the direction of rotation of the motor.

The output of IC3 is coupled to the fourth stage through coupling capacitor C6. The fourth stage of the sequential timer is built around IC4. This stage is identical to the second stage as it also provides delay if the process has to be repeated continuously. If the process completes in a single cycle, this stage is not required. IC4 triggers when the output of IC3 goes low.

Thus with the help of these four timer blocks, the motor first rotates forward for 4-45 minutes, stops for 1.75-10 minutes, rotates in reverse direction for 4-45 minutes and then stops for 1.75-10 minutes. 

Construction

The sequential timer for DC motor control is shown in Fig. and its component layout in Fig. Assemble the circuit on a PCB as it minimizes time and assembly errors. Carefully assemble the components and double-check for any overlooked error. Use proper IC base for the ICs. Before inserting the ICs, check all the supply voltages.

Connect the 6V power supply to CONN2 and supply for motor to CONN1. Motor M1 should be connected through a connector. Switch S2 should be connected to the PCB through wires.

Communication From 1G to 4G

Any radio telephone capable of operating while moving at any speed, battery operated and small enough to be carried by a person comes under the mobile communication systems. These communication systems may have different facilities. The different types of mobile communication systems are mobile two-way radio, public land radio, mobile telephone and amateur (HAM) radio.

Mobile two-way radios are one-to-many communication systems that operate in half-duplex mode, i.e., push to talk. The most common among this type is citizen band (CB) radio, which uses amplitude modulation (AM). It operates in the frequency range of 26-27.1 MHz having 40 channels of 10 kHz. It is a non-commercial service that uses a press-to-talk switch. It can be amplitude-modulated having double-sideband suppressed carrier or single-sideband suppressed carrier.

Amateur (HAM) radios cover a broad frequency band from 1.8 MHz to above 30 MHz. These include continuous wave (CW), AM, FM, radio teleprinter, HF slow-scan still picture TV, VHF or UHF slow-scan or fast-scan TV, facsimile, frequency-shift keying and amplitude-shift keying.

Present and past of mobile communications

Before I narrate the journey from 1G to 4G, let me explain the important technologies behind the phenomenal growth of mobile communication systems. Since the commercial introduction of advanced mobile phone system  service in 1983, mobile communication systems have witnessed an explosive growth. The most important breakthrough was the cellular concept.

Cellular concept. 

Cellular system works as follows:

An available frequency spectrum is divided into discrete channels, which are assigned in groups to geographic cells covering a service area. The discrete channels are capable of being reused in different cells with diameters ranging from 2 to 50 km. The service area is allotted a radio frequency (RF) transmitter, whereas adjacent cells operate on different frequencies to avoid interference.

Cellular telephones began as a simple two-way analogue communication system using frequency modulation for voice and frequency-shift keying for transporting control and signaling information. Other cellular systems are digital cellular system, cordless telephony, satellite mobile and paging. 

Analogue cellular phone.

In 1970, Bell Labs in New Jersey proposed a cellular telephone concept as advanced mobile telephony system . AMPS is a standard cellular telephone service placed into operation on October 13, 1983 by Illinois Bell. It uses narrow-band FM with a usable audio frequency band of 300-3 kHz and maximum frequency deviation of ±12 kHz for 100 per cent modulation. According to Carson’s rule, this corresponds to 30 kHz.

AMPS uses frequency-division multiple access (FDMA), where transmissions are separated in the frequency domain. Subscribers are assigned a pair of voice channels for the duration of their call. Analogue cellular channels carry both voice using FM and digital signaling information using binary FSK.

Digital cellular system.

It provides improvements in both capacity and performance. FDMA uses a frequency canalization approach to spectrum management, while time-division multiple access (TDMA) utilises a time-division approach. The entire available cellular RF spectrum is sub-divided into narrow-band radio channels to be used as a one-way communication link between cellular mobile units and base stations.

Multiple access technologies for cellular systems

A fxed amount of frequency spectrum is allocated to a cellular system. Multiple access techniques are deployed so that the users can share the available spectrum in an efficient manner.

For wireless communication, multiplexing can be carried out in three dimensions: Time (TDMA), frequency (FDMA and its variation OFDMA) and code (CDMA).

The available spectrum is partitioned into narrow frequency bands or frequency channels, which, in turn, are divided into a number of time slots. In case of North American digital cellular standard IS-136, each frequency channel is divided into three time slots, whereas in European digital cellular system GSM each frequency channel  is divided into eight time slots. Guard bands are needed both between frequency chan-nels and time slots.

The available spectrum in a frequency band called traffic channel. Different users are assigned different channels on demand basis. The user’s signal power is concentrated in a relatively narrow frequency band. All the analogue cellular systems used FDMA system.

Digital modulation keying

Communication systems often involve modulation of a carrier, which results in a bandpass waveform. A digital signal can be used to modulate the amplitude, frequency or phase of a sinusoidal carrier producing three different forms of digital modulation: amplitude-shift keying (ASK), frequency-shift keying (FSK) and phase-shift keying (PSK). In addition to these basic techniques, there are some modulation schemes that employ a combination of amplitude and phase modulation. It may be noted that unlike ASK signal, PSK transmission is polar. At the same time, ASK is a linear modulation scheme, whereas PSK is a non-linear modulation scheme. PSK has a superior performance over ASK.

Quadrature phase-shift keying (QPSK).

Digital modulation techniques mentioned above are spectrally inefficientin the sense that the available channel bandwidth is not fully used. Spectral efficiencycan be improved by using QPSK. It is a system for two message sources. In this system modulation carriers in phase quadrature are combined to form the output waveform. In QPSK the amplitude of the modulator waveform and modulator gains are made as nearly equal as possible.

Differential phase-shift keying (DPSK). 

DPSK is a modification of PS that avoids the need to provide synchronous carrier required for detection of PSK signals. It is an ingenious technique whereby the carrier reference is derived from the received waveform in the preceding bit interval by use of a 1-bit delay. In essence, the received waveform delayed by 1-bit duration serves as its own reference.

Data transmission using packet switching

This is done by supplying various addressed packets, which are interconnected to have the conversation. New dedicated paths are created for sending the data. From the multiple paths to the destination, any path can be used to send data. Cellular digital packet data was designed for optimal operation with an analogue cellular system, especially AMPS.

Short message service.

Short message service is the most common packet service that is supported on digital cellular networks like GSM, IS-136, EDGE and PDC . It is a store-and-forward/packet mode service that provides inter-working with the various applications and services within a fixed network. For message transfer between relevant network entities,control and signalling channels are generally used for data transmission.

General packet radio service (GPRS). 

GPRS essentially represents add-on capabilities to the basic voice-optimised cellular network that nevertheless maintain the essential characteristics of radio-access technology. You can use these using GPRS or GSM modules.

Enhanced data rates for GSM evolution (EDGE).

In order to enhance the data handling capabilities of 2G service, radio-access portion had to be modified. This modification was evolved in Europe in the form of EDGE. EDGE also supports a link adaptation mechanism that selects the best combination of modulation and encoding schemes based on the timevarying link quality.

EDGE concept applies to both circuit-mode and packet-mode data and is sufficiently generic for application to other digital cellular systems. It works in the 200kHz bandwidth with one or more high-level modulation schemes and a range of efficient coding methods. Modulation schemes are offset QPSK and offset 16 QAM.

GSM

Global system for mobile communications (GSM) was developed by the Group Special Mobile, which was an initiative of the Conference of European Post and Telecommunications  administrations. GSM was firs devised as a cellular system in a specific 900MHz band called the primary band. This primary band includes two sub-bands of 25 MHz each, 890-915 MHz and 935-960 Mhz.

GSM systems like Iridium, Globalstar and ICO use constellations of low-earth orbit (LEO) or medium-earth orbit (MEO) satellites and operate as overlay networks for existing cellular and PCS networks. Using dual-mode, these extend the coverage to any and all locations on the earth’s surface.

International Mobile Telecommunication-2000  is a standard developed by ITU for 3G. It ensures global mobility in terms of global seamless roaming and service delivery. An appreciation of the role of numbering and identities in mobility management, international roaming, call delivery, and billing and charging is important in understanding the operation of mobile and personal communication networks.

Personal communication satellite service uses LEO satellite repeaters incorporating QPSK modulation and both FDMA and TDMA.

The main advantages of GSM are international roaming (in harmony with ISDN principles assuring inter-working between ISDN and GSM) and features like privacy and encryption, frequency hopping, discontinuous transmission and short message service. Other facilities include call forwarding, barring, waiting, hold and teleconferencing.

Journey from 1G to 4G

1G system.

1G specifications were released in 1990 to be used in GSM. 1G systems are analogue systems such as AMPS that use FDM to divide the bandwidth into specific frequencies that are assigned to individual calls.

2G system. 

These second-generation mobile systems are digital and use either TDMA or CDMA method. Digital cellular systems use digital modulation and have several advantages over analogue systems, including better utilisation of bandwidth, more privacy, and incorporation of error detection and correction.

2.5G system. 

It was introduced mainly to add latest bandwidth technology to the existing 2G generation. It supports higher-data-rate transmission for Web browsing and also supports a new browsing format language called wireless application protocol (WAP). The different upgrade paths include high-speed circuit-switched data (HSCSD), GPRS and EDGE.

HSCSD increases the available application data rate to 14.4 kbps as compared to 9.6 kbps of GSM. By using four consecutive time slots, HSCSD is able to provide a raw transmission rate of up to 57.6 kbps to individual users.

All the eight time slots of a GSM radio channel are dedicated to GPRS, an individual can achieve as much as 171.2 kbps. But this has not brought any new evolution. EDGE introduces a new digital modulation format called 8-PSK . 

3G system. 

To overcome the short-comings of 2G and 2.5G, 3G has been developed. It uses a wideband wireless network that offers increased clarity in conversations. Countries throughout the world are currently determining new radio spectrum bands to accommodate 3G networks. ITU has established 2500-2690MHz, 1700-1855MHz and 806-960MHz bands. Here the target data rate is 2 Mbps. The data is sent through packet switching. Voice calls are interpreted through circuit switching.

3G W-CDMA (UMTS). Universal Mobile Telecommunication System (UMTS) or W-CDMA assures backward compatibility with 2G and 2.5G TDMA technologies. W-CDMA, which is an air interface standard, has been designed for always-on packet-based wireless service, so that computers and entertainment devices may all share the same wireless network and connect to the Internet anytime, anywhere.

W-CDMA supports data rates of up to 2.048 Mbps if the user is stationary, thereby allowing high-quality data, multimedia, streaming audio, streaming video and broadcast type services to consumers. With W-CDMA, data rates from as low as 8 kbps to as high as 2 Mbps can be carried simultaneously on a single W-CDMA 5MHz radio channel, with each channel supporting between 100 and 350 simultaneous voice calls at once, depending on antenna sectoring, propagation conditions, user velocity and antenna polarisation.


4G system. 

It offers additional features such as IP telephony, ultrabroadband Internet access, gaming services and HDTV streamed multimedia. Flash-OFDM, the 802.16e mobile version of WiMax , can support cellular peak data rates of approx. 100 Mbps for high-mobility communications such as mobile access and up to 1 Gbps for low-mobility communications such as nomadic/local wireless access, using scalable bandwidths of up to 40 MHz. The infrastructure for 4G is only packet-based.

Innovation in the Internet of Things

At one point of time, the definition of the Internet of Things (IoT) revolved around radio frequency identification (RFID) tags and applications monitoring them. Slowly, it has evolved to encompass everyday products such as mobiles, air-conditioners, refrigerators, televisions, heart rate monitors, fitness accessories and equipment, disks and modems, and even LED lights and power sockets. 

Either these products are Internet-enabled, or use a smartphone, tablet or other mobile devices and their applications as a gateway to connect to the Web, thereby attaching aspects of information and connectivity to everyday objects… which is what the IoT is all about. In this episode, let us take a look at some recent consumer electronics products that fit into the IoT schema.

A GPS device that projects routes on the road

A navigational aid for cyclists developed by designer Kim Tae-Jin. When the designer felt that traditional GPS navigation devices are distracting—people tend to look at the device rather than the road, leading to accidents, he went about developing a navigation aid, which uses powerful directional laser arrows that are visible even during the day, to project routes and other information straight ahead of the cyclist on the road, rather than on the device. The designer is confident this will be more convenient than traditional instruments, and also avoid accidents.

Inside: Open Sight works like existing GPS devices, but includes high-intensity laser projection, which is bright enough to be seen just as well in broad daylight as in low light and at night. The projection mechanism displays the route and other information straight ahead of the cyclist, on the road. So, there is no need to keep looking into a small screen. A touch-enabled control panel allows the user to easily control the features. Open Sight also includes a variety of sensors that measure cycling speed, distance covered, and so on. The device is pedal-powered, which means it charges using kinetic energy generated by the pedaling motion. It has an on/off switch to avoid power wastage when not in use. In short, the innovation here is the laser projection, which avoids distraction and improves safety for the cyclist. 

Remotely control you devices using your mobile

Belkin has launched a series of home automation products called WeMo that let you control your home electronics from anywhere using a mobile app. They are in line with the ‘connected home’ concept—a key aspect of the IoT. The WeMo Switch, a part of this series, is an intelligent power socket that works with an iOS application. It makes use of your home’s Wi-Fi network to provide wireless control of TVs, lamps, stereos, and more. Using mobile Internet, you can also control the devices from anywhere. Simply download the free WeMo app, plug the switch into an outlet in your home, and plug any device into the switch. You can turn the device on or off, or even set schedules for its operation. For example, you can program the coffee maker to switch on and brew for 10 minutes just before you arrive home, so you get fresh coffee when you get in! There is also a motion-sensor based product called WeMo Motion that lets you program devices to work based on the presence or movement of people.

Inside: WeMo Switch looks like any normal power switch, and can also be controlled physically like normal switches. WeMo is Wi-Fi capable—and can be remotely controlled through an app that runs on iOS 4.3 or higher. Belkin is apparently also addressing customer requests for an Android version of the app. Apart from simple remote on/off controls, WeMo can also be scheduled to switch on or off at specific times; or can be programmed to react to situations using a great service called IFTTT, which is actually the most innovative aspect of WeMo. IFTTT stands for ‘if-this-then-that’. You can setup WeMo equipment to react to changes. For example, you can set it up to switch on when somebody comes in. Better still, it is Web-enabled, so you can link the functioning of devices to say weather reports, or you can turn it on or off using Twitter or other social media messages. WeMo can also talk back—it can post information or trigger events on Facebook, Twitter, etc., send you an SMS, or update Google Calendar!

Don’t know what to cook? Ask your fridge

Imagine a refrigerator that keeps track of the inventory inside, and warns you when something inside is too old, or suggests recipes based on ingredients you have, or reminds you to do your shopping when the veggie or milk tray goes dry! Well, Samsung’s new smart refrigerator, the T9000, is capable of this and more.

Inside: The Samsung T9000 is a 32-cubic-foot, four-door fridge that has two compressors, three evaporators and a large number of various sensors. It is Wi-Fi enabled, and includes a 10-inch LCD touchscreen tablet on the door. The fridge runs on the Android OS, and includes apps such and Epicurus and Ever-note to help users choose recipes, create shopping lists, and manage the expiration dates of items like yogurt and milk. The display may also be used to keep track of news and weather, to Twitter or even display photo slideshows on the fridge door. The device also integrates with Google Calendar, and is capable of syncing with your smartphone or tablet. You can even share recipes, notes and photos with family and friends. The application also makes it easy to setup the refrigerator’s settings such as temperature and humidity. It extends the capability to change the functionality of one of the fridge’s compartments. By altering the settings you can convert it into a freezer or normal fridge, depending on requirements.

Record a game from the ball’s view

The game from several points-of-view in order to train their players better, develop strategies and improve the moves. Cameras and image processing software have proven very helpful in this task—providing close views from multiple angles, trajectory analysis and more. However, what has been missing till date is the view from the ball! Ball Cam is a new technology developed by researchers at the Carnegie Mellon University and the University of Electro-Communications in Tokyo, which allows a video camera to be embedded in a ball, thereby capturing smooth video as it spins through the air. While this might be illegal in official games, such recordings will surely be useful for training purposes. What is more, it might even vividly record the expression on a player’s face when he misses a ball!

Inside: BallCam features a high-definition, wireless GoPro HERO 2 camcorder inserted into a hole on the side of a rubber-sheathed plastic foam football. One of the biggest problems in recording video from a spinning object as fast as a football is the resulting blur. However, BallCam uses a special algorithm to process the video from balls spinning at up to 600 rpm. The algorithm is designed to monitor and discard video frames that show only the sky. When the remaining frames are stitched together, the result is a relatively smooth, wide-angle view from the side of the football. The stitching software is similar to what NASA uses to stitch together images from its Mars rovers. So, the technology is quite complex—and certainly not ‘playful’ stuff! The researchers say that the prototype can be enhanced to include multiple cameras and better camera sensors too.

Come Forth Into the Light of Things

The Internet of Things weaving its magic to revolutionist lighting. The latest bulbs let you adjust the intensity and colour to mimic natural light. These can transform from a bright white-yellow like the morning Sun to a warmer and more golden-red part of the spectrum in the afternoon. Or these can allow you to simulate an entire golden forest, which is what Japanese electronics component manufacturer ROHM did just last year. What is enabling all this?

What happened to hardware

The change from emitter technology to chip on board technology, different soldering processes for different chip manufacturers, driver requirements for various wattage and much more. This is a continuous process and a manufacturer needs to adapt according to this dynamic change.

Belkin WeMo devices run on  AR9331 system on chip SoC. Disney Research published a white paper where they discuss an innovative LED-to-LED communication system that uses the same SoC along with an 8-bit ATmega328p running Visible Light Communication VLC firmware and connected to an amplification board. It uses visible light to send data at a rate of up to 1kbps. The do-it-yourself bulbs are designed to interact with other gadgets that may not have full Wi-Fi connectivity and instead read data using VLC that uses visible light between 400THz and 800THz.

NXP’s Green Chip iSSL and Green Chip iCFL bring together wireless connectivity, energy-efficient lighting and low-power standby in a solution that supports software stacks like Zigbee and JenNet. JenNet-IP is a 6LoWPAN mesh-under-tree network with low memory footprint, specifically targeting low-power IEEE 802.15.4 based networking for residential and industrial applications. ZigBee LightLink is a standards based solution targeting in-room lighting for residential applications.

LED SENSE is a new low-voltage driver architecture created by a company named Terralux. The company claims that they program LM-80 curve  into each product and monitor the temperature to ensure the LED is not overdrive for ambient temperature, and also ensure that their products comply with NEMA SSL6/7 dimming standards.

Twilight Switch is a sunlight based automatic on/off sensor that switches on at dusk and switches off at dawn.“Improved dimming is possible by Android devices, infrared sensors and Bluetooth controllers these days. You also see motion sensors based light on/off control.

FLYON is a lighting device being developed by Quantum Dots, which glows while floating in air without any wired connection. “It works on the amalgamation of maglev and Witiricity. FLYON involves lifting forces, electromagnetic suspension, position sensing, magnetic flux, flux orientation and frequency of operation including Witiricity. Witricity power sources and capture devices are specially designed magnetic resonators.

MaGIC LED die manufactured on the company’s patented GaN-on-Silicon technology. The blue die is referred to in the company’s press release as a blue pump for its ability to pump phosphor to a white colour range.

Overall, there seems to be a focus on improving the communications aspect of lighting as well as enabling greater precision with which these can be controlled.

What happened to the controls

A virtual home for every light bulb—that is what the future of smart lighting promises us. By having an Internet address for every bulb to call home, we gain the ability to call it up and control it as we please from anywhere across the globe through the Internet.

Sensor based lighting systems are now being made smarter to fit in with human behaviour and responses. For instance, motion sensor systems that switch lights based on people entering the room can now differentiate between a pet and a person. These also do not switch off immediately when a person leaves, instead keep the light on for a few minutes as people tend to feel creepy when lights behind them shut off as they walk through a hall.

Lutron and Insteon have had their lighting kits designed to work flawlessly with Apple’s HomeKit devices. This means users can control lighting by speaking to their phone or watch.

Cisco Smart+Connected City Lighting solution combines with their City Multi Sensor Node to create a light-sensory network. These standards based systems gather a wide variety of data from the environment, including levels of humidity, CO2 and O2, UVA and UVB light, particulate matter, motion and seismic activity, video, sound and more.

Plugging in some smarts

Build your own smart lighting system? There are some amazing products available that can let you plug in a smart lighting system into your home without having to get your hands dirty with code.

Philips Hue has stepped things up a notch. You can now use your iOS phone to not just switch on and off bulbs, but also pick colour, brightness and program timing, too. It also lets you use If This Then That service to get your lighting system to respond to situations like flashing red for a call.

Bluetooth Smart bulb rated at 7W and 430lm. Belkin has a similar functioning solution in its WeMo branded LED bulbs. LIFX is a similar product but works on Wi-Fi instead of Bluetooth Low Energy. Belkin has also brought out a WeMo light switch that lets you control dumb bulbs with your phone.

If you really want to take things ahead with your existing lighting and home electronics, then Light wave RF has a solution to swap your home’s sockets with their Internet-enabled switches. GE Link is another option that lets you remotely control and sync to a connected device through an app called Wink.

Those on a budget can look at Cree Connected LED, as these are one of the most inexpensive bets available. For a more all-inclusive integration, Lu-tron has a product named Home Works QS that can control not just light but interior and exterior systems, audio-visual and heating, ventilation and air-conditioning, making it more of a home environment control system. In line with this concept, it also lets you create scenes, which are preset light and shade levels. 

What will happen to the switch

Smart lighting is built on the premise that not only can you control your lights from anywhere, you can also set these up such that these do the controlling on their own. That means no more fumbling for the light switch when you get back home at night, or when you make your way to the kitchen in the middle of the night.

Raspberry Pi Zero bakes in a camera connector

The cheapest and most compact version of the Raspberry Pi has just seen a rather nifty little addition in the form of a camera connector.

As announced on the Pi blog, the new connector for the Pi Zero fits snugly onto the right-hand side of the board, as you can see in the image above.

And the good news is the price of the Pi Zero remains the same, so it'll still run you to just £4 ($5). To hook up your camera, you'll also need a custom 6-inch adapter cable, which goes under the name of the Camera Cable: Raspberry Pi Zero Edition, and will cost a further £4.

Size matters

The camera connector is smaller on the Pi Zero, unsurprisingly, so you won't be able to use an existing cable from your normal-sized Raspberry Pi.

If you missed it, a new camera board was also launched for the Raspberry Pi last month, which is an eight megapixel affair and it comes in a normal visible light version and an infrared flavor with both being pitched at £19 ($25).

So you can now hook up this new snapper featuring a Sony IMX219 sensor to the Pi Zero.

The Pi Foundation says it has shipped out 30,000 more units of the Zero, but we doubt that stock will last that long, as given the minimal outlay, these have proven to be extremely popular. 

IoT Vehicle Simulation System

The OBDII breakout module connected to the Vehicle Simulator/Recorder module:

Here is a picture showing the card stack making up the vehicle simulator/recorder module:

A little additional perspective :

When thinking about how the internet-of-things will evolve, it is easy to predict vehicles will be a significant focal point for consumer applications, since vehicles currently represent by far the biggest technology expenditure/investment by the average consumer. Vehicles are very complex machines incorporating multiple micro-controllers communicating via on-board buses. The level of electronic technology in vehicles has exploded and there is a large amount of vehicle data readily available on the diagnostic bus which is used locally, but not yet used for the vast number of potential external applications.

      There will be whole sectors of applications such as :

• safer driver operation of the vehicle, fewer distractions, more automation
• more effective driving methods
• ways to save fuel
• safer mechanical performance, better & more timely maintenance warnings
• lower cost operation and lower maintenance costs
• better and more timely driver information
• better advanced traffic warnings and route planning
• vehicles better designed to address owner needs and habits
• accident response applications
• vehicle-to-internet applications
• vehicle-to-vehicle communications
• applications that use data from multiple vehicles

Initial Simulator Concept :

Initially the system will need to be able to provide OBD2 data just as a real vehicle would in response to queries on a CAN bus or K-Line interface. To ensure realistic data, trip data will be collected from real vehicles the project will include a data collection system as well as a playback / simulation system. During a simulated trip, previously recorded data can be interpolated to provide appropriate data to any bus queries.

An attempt will be made to keep the software modular enough that it won't be difficult to replace fault code simulations with better simulations when more is understood about their behavior and also to replace recorded trip scenarios with computed simulations, if and when they get developed.

Objectives :

The primary objective for this project is to provide a vehicle simulator system that provides realistic enough data, primarily in electronic form, to allow developers to test their OBD2 reader prototypes & data applications in a lab instead of needing to test in a vehicle.

An secondary objective is to make the vehicle simulator such that it can be used to demonstrate new products and applications indoors at trade shows or sales presentations.

A third objective is to make the vehicle simulation system a modular platform that can be extended and upgraded to become a more accurate simulation for more vehicles.

An auxiliary objective is to create a data collection system that will continuously query a vehicle during a trip and record real data with time stamps.

VTR Block Diagram :

System Platform :

In order to make a compact open system that can be easily setup for testing or demonstration at any location the Beagle bone Black (BBB) has been chosen as the platform. Several of them are being supplied by the project sponsors Texas Instruments, Cisco and element. This will allow a data collection system (RTR) to collect trip data from a real vehicle, then a simulator system VTR can simulate this trip for the same data collection unit to see if it collects the same data from the simulation as it did from the real trip. This dual system provides an easy way to validate the system.

System Design :

OBD2 data provides a lot of information about what is occurring inside vehicle systems, but it does not necessarily provide everything desired in a simulation, such as location and orientation of the vehicle, distance traveled, and time stamps on all data.

The Beagle bone Black (BBB) has a CAN bus capability, but a custom cape will be needed to translate this to OBD2 signals and add in a K-Line interface. This cape will also include a GPS module and a 10 channel sensor suite - 3 orthogonal linear accelerometers, 3 orthogonal angular rate sensors, 3 orthogonal magnetometers and an absolute pressure sensor. These sensors are not needed in the simulator system, but will allow more sophisticated sensor data to be collected when the device is used for recording real trips and this data can later be presented by the simulator. The VTR/RTR cape will also include a Bluetooth module - when in VTR mode it will allow generation of fault codes and control of the VTR from a smart phone, when in RTR mode it will allow connection to a Bluetooth OBD2 interface or possibly a smart phone.

RTR Block Diagram  :

Project Plan :

The first major task is to set up 2 Beagle bone Blacks to communicate with each other over a CAN bus. This will allow us to gain an understanding of CAN bus messages and protocol. There are a bunch of associated sub tasks such as obtaining appropriate hardware, organizing software development tools, researching what is available on open source, writing some test code, etc.

• Design, build and test an OBD2 cape for the BBB.
• Connect a BBB to a vehicle and send and receive OBD2 messages.
• Write the RTR data collection firmware.
• Write VTR simulation firmware.
• Test and validate system.

Both vehicle simulator and vehicle recorder systems have been built and they communicate with each other fine over the CAN bus.

We are still having a devil of a time sorting out OBDII communications with a real vehicle. This is the main reason for such a long delay since our last posting, however I figured we need to post at least an update.

This screen shows location coordinates when the GPS finds enough satellites. Right now it is still showing UTC time.

This is a little warm because I have some bright lights shining directly on the module.

We are still sorting out some of the analog channels...

The LCD updates "instantly" in response to the keypad scroll buttons because it is interfaced via SPI.

Dusk-Dawn Controller

Solar streetlights can be easily integrated with a dusk-dawn controller by simply employing a pnp transistor and a few resistors where the solar panel itself works as the sensor. But what about other lighting sources that do not employ solar panels such as automatic lighting systems in small wind turbines, automatic lighting in cars or battery based systems where automatic lighting is necessary?

A simple, low-cost, yet an effective solution for the dusk-dawn controller circuit is described here.(a) dawn mode, (b) dusk mode and (c) prototype

Circuit and working

Circuit diagram of the dusk-dawn controller is shown in Fig. It is built around a light-dependent resistor (LDR), n-channel MOSFET IRF640 (T1), 12V LED light or a small inverter (100W) and a few other components.

The 12V battery-operated circuit is designed such that the common battery supply is used for operating the circuit as well as for load, that is, for power LED/small inverter circuit. Resistors R1 and R2 are used as a voltage divider and a current limiter in the circuit, respectively. LED is used as circuit de-activation indicator. LDR is the main component for actuation of the dusk-to-dawn sensing. The n-channel MOSFET IRF640 is for the switching action of the LED light or the small inverter connected to the system through switches S1 and S2, respectively.

With daylight falling on LDR , resistance of LDR becomes low, a small current flows through LED and it glows. At the same time, due to low voltage across LDR, MOSFET IRF640 does not trigger. So load  remains off.

But when the surrounding area of LDR (dusk mode) is dark (at night), resistance of LDR becomes very high, no current flows through LED and it does not glow. At the same time, due to higher voltage across LDR, IRF640 triggers. So load light comes on, provided switch S1 or S2 is on.

IRF640 can handle a maximum current of approximately 18A, but you can limit its application to approximately 8A-9A only, based on which the heat-sink is attached to the 

MOSFET.

PCB and component layout

After assembling the circuit, enclose it in a suitable box. The unit should be fixed on the pillar in such a way that the daylight falls directly on LDR.