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3 Jun 2014

There is cool contest for EEs, with actual prizes running right now.  EEWeb.com is running the “2014 European Design Freedom Contest”  (at http://www.eeweb.com/freedomcontest) and the prizes include iPads and iPods as well as a football table, espresso machine, or bike.  You’ll get to design projects using the Freescale Freedom Kinetis ARM based development platform.

The contest uses free online tools from Digi-Key.  The first part of the contest uses Scheme-It for you to generate a block diagram of your contest entry that uses one of the 10 available Freescale Freedom Platforms; the project can be a solution to a real problem or something novel.  This first phase of the contest runs through the end of June.

In the second phase, create a PCB design of your project.  You can also go with a software submission using ARM mbed studio online software (mbed.org).  The 2nd phase runs through Oct 10th.

EEWeb.com – 2014 European Design Freedom Contest - [Link]

31 May 2014

This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode. When the beam path breaks, alarm will be triggered. The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1.

The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its reset pin becomes high. When the Laser / IR beam breaks, current through the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated.

A simple IR transmitter circuit is given which uses Continuous IR rays. The transmitter can emit IR rays up to 5 meters if the IR LEDs are enclosed in black tubes.

555 Photodiode alarm - [Link]

27 May 2014

Hobby grade R/C cars with high voltage batteries require some form of voltage regulation.  The batteries in those vehicles are typically 11.1V to 22.2V, while the required voltage for the radio system components is 6.0V to 7.4V depending on their ratings. Current draw with some of these systems normally ranges from 3A to 6A, as well.  Some electronic speed controls in the R/C industry have this capability, but many do not, and it is a common point of failure for those that do.

This circuit provides the necessary regulation and power supply for high powered R/C systems common today.  The center of the circuit is the RT8298, a synchronous high voltage Buck Converter that can support the input voltage range from 4.5V to 24V and the output current can be up to 6A.  The voltage dividers that set the output voltage to 6V or 7.4V are controlled by a simple switch that the user sets to the voltage they want.

R/C Car Voltage Regulator – [Link]

24 May 2014

Electronic scales are widely used in kitchens and bathrooms because they can quickly make accurate weight measurements.

A load sensor called a load cell is used for weight measurement.  Because the output voltage of this sensor is very small, it is amplified by an operational amplifier (op-amp) and input to an A/D converter.  A microcontroller (MCU) converts the signal to weight based on the conversion results of the A/D converter and displays it.

Renesas offers a lineup of microcontroller products for meeting their customers’ needs, such as the RL78/L1x, 78K0/Lx3, and R8C/Lx series with built in LCD driver for designing small and inexpensive models.  For highly precise measuring, they offer the 78K0/Lx3, the H8/38086R group, the RX21A group, and other with built-in high precision ΔΣ (delta-sigma) A/D converter.

Renesas MCU for Electronic Scales - [Link]


19 Apr 2014

Electric fans continue to sell at a steady pace, despite the widespread use of air conditioners. Recently, models have begun to appear on the market with features such as a variety of blade shapes, silent operation, and better air efficiency. Electric fans are also increasingly being used in concert with air conditioners to save electricity through better cooling efficiency.

Renesas offers microcontrollers such as the 4286 Group which is ideal for remote control function, the RL78 Family, the R8C Family, and the 78K Family which are ideal for system control, and TRIACs and photocouplers for peripheral components. We offer the best solutions for electric fan systems.

Renesas Computerized Electric Fan - [Link]

17 Apr 2014

Compact battery chargers require overcurrent protection and temperature monitoring to ensure safety.  These chargers also need to fit into small form factors, and generally have a lot of pressure to also be very inexpensive, but only have to provide a simple charging ability.

Furthermore, compact packaging is required to integrate the battery charger into a system.  Renesas has 8/16-bit microcontrollers available in compact packages with as few as 10 pins, making them ideal for these applications.

Recommended Products:

78K0/Kx2: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit and on-chip oscillator; low power consumption,30 to 80 pins.

78K0/Kx2-L: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit, on-chip oscillator, and operational amplifier; ultra-low power consumption, 16 to 48 pins

78K0S/Kx1+: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit and on-chip oscillator; 10 to 30 pins

R8C Family: Timer, 5 V operation, and Small Package

P-ch MOSFET: Low on-resistance, compact low-profile

Renesas Battery Charger Solutions - [Link]

8 Apr 2014

Home automation is the residential extension of building automation. It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC (heating, ventilation and air conditioning), appliances, security locks of gates and doors and other systems.  This provides better convenience, comfort, energy efficiency and security. Home automation for the elderly and disabled can provide better quality of life for persons who might otherwise require caregivers or institutional care. Nowadays, semiconductor companies develop IC that integrates the system as a whole. One of which is NXP Semiconductors which they develop Home automation modem IC TDA5051A.

The TDA5051A is a modem IC, specifically dedicated to ASK transmission by means of the home power supply network, at 600 baud or 1200 baud data rate.  Its single chip power line modem is equipped with protection of its output power stage and AGC (Automatic Gain Control) of input signal. With simple coupling network, this power line modem is compliance with EN50065-1 power line communication standard. This power line modem circuit uses ASK (Amplitude Shift Keying) for the modulation, and operates on 5V supply.

A home automation system integrates electrical devices in a house with each other.  Devices may be connected through a computer network to allow control and may allow remote access from the Internet. Through the integration of information technologies with the home environment, systems and appliances are able to communicate in an integrated manner, which results in convenience, energy efficiency, and safety benefits.

Components:

  • TDA5051AT modem IC
  • Schottky Diode
  • 68Ω Resistor
  • 2.2MΩ Resistor
  • 7.3728Mhz Oscillator Clocks
  • T 630mA Fuse
  • General Diode (2 units)
  • 2uF Capacitor
  • 47 nF/X2 Capacitor (3 units)
  • 470 µF Capacitor
  • 100 µF Capacitor
  • 1 uF Capacitor
  • 10 nF Capacitor
  • 5 µF Capacitor (2 units)
  • 1 mH Inductor
  • 47 µH Inductor (2 units)
  • 1N4006 Diode
  • 250 Supply Vac
  • Microcontroller
  • Positive Voltage Regulator

Power Line Modem for home Automation - [Link]

2 Apr 2014

The PCA9508 is a CMOS integrated circuit that supports hot-swap with zero offset and provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) for I2C-bus or SMBus applications. While retaining all the operating modes and features of the I2C-bus system during the level shifts, it also permits extension of the I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Using the PCA9508 enables the system designer to isolate two halves of a bus for both voltage and capacitance, and perform hot-swap and voltage level translation. Furthermore, the dual supply pins can be powered up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance.

PCA9508 has B-side and A-side bus drivers. The 2.7 V to 5.5 V bus B-side drivers behave much like the drivers on the PCA9515A device, while the adjustable voltage bus A side drivers drive more current and incur no static offset voltage. This results in a LOW on the B-side translating into a nearly 0 V LOW on the A side.

The hot swap feature allows an I/O card to be inserted into a live backplane without corrupting the data and clock buses. Control circuitry prevents the backplane from being connected to the card until a stop command or bus idle occurs on the backplane without bus contention on the card. Zero offset output voltage allows multiple PCA9508s to be put in series and still maintains an excellent noise margin.

Components:

  • PCA9508D CMOS integrated circuit (3 units)
  • BUS Master
  • Slave 400kHz (3 units)
  • 10kΩ Resistor (6 units)
  • Ground Source

Hot swap level translating I2C repeater - [Link]

27 Mar 2014

We are always vulnerable to thieves but we don’t know when will they strike. When they do, it will be too late for us to notice that our property was already taken. This project helps alert the owner if a thief is picking a lock. It can be used on doors, luggage or anything else with a lock.

The concept is simple, if the lock is opened without our consent, an alarm will be turned on indicating an intruder. This circuit is based on a NAND gates configuration that will turn the switching side on or off.

In this project we used the HEF4011B, a quad 2-input NAND gate. The outputs are fully buffered for the highest noise immunity and pattern insensitivity to output impedance. The configuration of the IC HEF4011B produces a HIGH output if the input is HIGH. Based on the figure, when the wire loop is closed, the IC HEF4011B will have a LOW input, and when the wire loop is triggered, the IC HEF4011B will have a HIGH input which will make its output also HIGH. The HIGH output of the IC HEF4011B will then be inputted to the base of the BC547 transistor allowing the current to flow on the relay switching the indicator or the buzzer ON.

Components:

  • HEF4011B quad 2-input NAND gate
  • BC547 transistor
  • 1N4007 diode
  • 1kΩ resistor
  • 4.7kΩ resistor
  • 0.1µF capacitor
  • Relay
  • 5V dc power source

Anti-theft Security Alarm Circuit – [Link]

20 Mar 2014

This is another common device people use everyday, in which a circuit drives the motor found in our watches or clocks to determine the time.

The circuit is mainly operated by PCA1462U IC, specially suited for battery-operated quartz-crystal controlled wrist watches. The quartz crystal is used to input an oscillated signal to the PCA1462U IC then produces an output of pulses that drives the stepping motor ON.

The IC used in this circuit is specialized for this application featuring an amplitude regulated 32KHz oscillator, with excellent frequency stability resulting in a high immunity from oscillator-to-leakage currents. The loss of motor steps is not possible because of an on-chip detection on the induced motor voltage, this output is applicable for different types of bipolar stepping motors. This IC also has a very low current consumption; typically 170 nA, and the time calibration of the pulses is electrically programmable and reprogrammable (via EEPROM).

Components:

  • PCA1462U CMOS integrated circuit
  • 1.55V dc power source
  • Quartz Crystal Oscillator
  • Stepper Motor

Quartz-crystal Controlled Wrist Watch – [Link]



 
 
 

 

 

 

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