Solar Minty, DHT22 , Waterproof DS18B20 , PH Probe

This is a work in progress project which uses a Solar charging MintyBoost to power an Arduino with a Proto Screw Shield on it. Attached is a 2X16 LCD using the I2C Backpack, a DHT22 Temperature and Humidity Sensor, a Waterproof DS18B20 Sensor and a 5V analog PH Probe/Adapter.

PT4115 continuous conduction mode inductive step-down converter

The PT4115 is a continuous conduction mode inductive step-down converter, designed for driving single or multiple series connected LED efficiently from a voltage source higher than the total LED chain voltage. The PT4115 operates from an input supply between 6V and 30V and provides an externally adjustable output current of up to 1.2A. Depending upon the supply voltage and external components, the PT4115 can provide more than 30 watts of output power. The applications of the PT4115 include Low voltage halogen replacement LEDs, Automotive lighting, Low voltage industrial lighting, LED back-up lighting, Illuminated signs, SELV lighting, LCD TV backlighting.

Digital voltmeter using ICL7107

The circuit given here is of a very useful and accurate digital voltmeter with LED display using the ICL7107 from Intersil. The ICL7107 is a high performance, low power, 3.5 digit analog to digital converter. The IC includes internal circuitry for seven segment decoders, display drivers, reference voltage source and a clock. The power dissipation is less than 10mW and the display stability is very high.

The working of this electronic circuit is very simple. The voltage to be measured is converted into a digital equivalent by the ADC inside the IC and then this digital equivalent is decoded to the seven segment format and then displayed. The ADC used in ICL7107 is dual slope type ADC. The process taking place inside our ADC can be stated as follows. For a fixed period of time the voltage to be measured is integrated to obtain a ramp at the output of the integrator. Then a known reference voltage of opposite polarity is applied to the input of the integrator and allowed to ramp until the output of integrator becomes zero. The time taken for the negative slope to reach zero is measured in terms of the IC’s clock cycle and it will be proportional to the voltage under measurement. In simple words, the input voltage is compared to an internal reference voltage and the result is converted in a digital format.

The resistor R2 and C1 are used to set the frequency of IC’s internal clock. Capacitor C2 neutralizes the fluctuations in the internal reference voltage and increases the stability of the display.R4 controls the range of the voltmeter. Right most three displays are connected so that they can display all digits. The left most display is so connected that it can display only “1” and “-“.The pin5(representing the dot) is connected to ground only for the third display and its position needs to be changed when you change the range of the volt meter by altering R4. (R4=1.2K gives 0-20V range, R4=12K gives 0-200V range ).
Circuit diagram.

Notes.

    Assemble the circuit on a good quality PCB.
    The circuit can be powered from a +/_5V dual supply.
    For calibration, power up the circuit and short the input terminals. Then adjust R6 so that the display reads 0V.
    The ICL7107 is a CMOS device and it is very sensitive to static electricity. So avoid touching the IC pins with your bare hands.
    The seven segment displays must by common anode type.
    I assembled this circuit few years back and it is still working fine.

EPC2LC20 Configuration Device

The EPC2LC20 is a Configuration Device which is designed for SRAM-Based LUT Devices.

EPC2LC20 absolute maximum ratings: (1)Supply voltage: -0.2 to 7.0 V With respect to ground; (2)DC input voltage: -0.2 to 7.0 V With respect to ground; (3)DC VCC or ground current: 50 mA; (4)DC output current, per pin: -25 to 25 mA; (5)Power dissipation: 250 mW; (6)Storage temperature: -65 to 150℃; (7)Ambient temperature: -65 to 135℃; (8)Junction temperature: 135℃.

EPC2LC20 features: (1)Serial device family for configuring APEXTM II, APEX 20K (including APEX 20K, APEX 20KC, and APEX 20KE), MercuryTM, ACEXR 1K, and FLEXR (FLEX 6000, FLEX 10KE, and FLEX 10KA) devices; (2)Easy-to-use 4-pin interface to APEX II, APEX 20K, Mercury, ACEX, and FLEX devices; (3)Low current during configuration and near-zero standby current; (4)5.0-V and 3.3-V operation; (5)Software design support with the AlteraR QuartusR II and; (6)MAX+PLUSR II development systems for Windows-based PCs as well as Sun SPARCstation, and HP 9000 Series 700/800.

Measuring and Test Circuit 2N7002

                                    2N7002

Constant off-time switching regulators offer several advantages over constant-frequency designs The only potential problem is that the switching frequency Increases with nsmg input voltage In designs that have large ratios of the high line to low-line supply voltage,this frequency shift can get quite large As a result,the switching losses can become excesslve at high input voltages To offset this problem,the simple circuit shown detects the high input voltage condition and lowers the switching frequency to keep switching losses under control The frequency-shift circuit consists of D3,R8,Q1,and C12 When Vin exceeds the zener voltage plus the FET threshold,Q1 turns on and adds an extra timing capacitor(C12) in parallel with the timing capacitor (C10) This increases the off-time,lowering the frequency.

LM393N integrated Circuits (ICs)

A TMOS power FET, Q1, and an LM393N comparator provide a high-efficiency rectifter circuit. When VA exceeds VB, U1's output becomes high and Q1 conducts. Conversely, when VB exceeds VA, the comparator output becomes low and Q1 does not conduct.

The forward drop is determined by Q1's on resistance and current I. The MTH40N05 has an on resistance of 0.028 Ω; for I = 10 A, the forward drop is less than 0.3 V. Typically, the best Schottky diodes do not even begin conducting below a few hundred mV.

Schematics LM358 Op Amp

In this schematic, a piezo is the sensor. Piezos generate voltage when physically bent or deformed, the the foltage is in the millivolt range. The direction that the piezo is deformed determines the polarity: bend it one way, get a positive voltage. Bend it the other way, get a negative voltage.

In this circuit, the piezo is put through a full-wave rectifier bridge (the four diodes) to make its voltage always positive. The output of the bridge is sent into one of the LM358's amplifiers that's configured as a voltage summing amp. The output of that amp is then fed into the other amp on the LM358 that's configured as a DC voltage gain amp. The output from the second amp is approximately 0.2 - 3.0 V DC.

Mono Power Amplifier A1015, BD140 ,TIP2955

Mono Power Amplifier - A1015, BD140 ,TIP2955 Circuit Diagram


Typically audio amplifier stereo amplifier to a two amplifier. And if a mono amplifier is a single speaker. However this circuit command be present extended to the mono two loudspeaker.But not a equivalence or else serialization access.This makes it needless impedance of the speaker has altered.But will remain to utilize the spokeswoman as a replacement for of the resistance - Collection Peter (RC) of the transistor.The circuit can be alive prolonged to 2 loudspeaker itself.

What time raising the power supply circuit and the audio to input. the audio sign coupling to through the C1 and R1 to increase with the Q1.Which Q1 serves like the Regional Pre amp amplifier to power up to a one point.already conveyance it to Q2.Which Q2 is connected to emitter follower circuit.be active as a driver amplifier intimate section from the pre amp section provides added power to drive the Q3 perform. and Q3 motivation provide while a Regional Power amp amplifier output to the spokeswoman.The opinion of the audio intimate through the VR1 and R2 to enter the pin B of Q2.To control the stability of working instead of well brought-up.This circuit is an output of 40 milliwatts watts of distortion of the gesture rate is by the side of 0.1 percent.And frequency response from 15 Hz - 200 kHz.

GP2D12 distance sensor 1N5819

During 250 ms, sensor is configured as a light sensor (powered), C1 charges through D1 up to SENSOR+ voltage. Low drop regulator U1 generates a 5V regulated supply. Q1 is blocked by D2 (D2 maintains base to a voltage higher or equal to its emitter voltage), so GP2D12 is not powered. Q3 is non-conducting too, preventing current flow through D3/R5/Q2. So the only significant current diverted from C1 charging is through R1 (less than 2 mA), and at the end of this phase C1 is fully charged.

During the following 50 ms, sensor is configured as a touch sensor (passive). SENSOR+ is now only pulled up to +5V through 10Kohm (inside RCX), insufficient to block Q1. Q1 and Q3 are then conducting, and GP2D12 is powered. Q2, mounted as an emitter follower, buffers GP2D12 output and its value is available to RCX through D3 and R5.



Sample code to read sensor:

    SetSensor(SENSOR_1,SENSOR_LIGHT);
    
    Wait(25);
    
    SetSensor(SENSOR_1,SENSOR_TOUCH);
    
    Wait(5);
    
    SetSensorMode(SENSOR_1,SENSOR_MODE_RAW);
    
    distance=SENSOR_1;
    
    SetSensor(SENSOR_1,SENSOR_LIGHT); //Enable C1 charge as soon as possible



Component selection

    D1 prevents destroying the sensor in case of reverse connexion. I didn't use the full bridge rectifier used in Lego sensor that enables sensors to work when connected backwards (number of needed diodes jumps from 3 to 8 !). I considered that someone able to build this sensor is also able to connect it in the right way... For those who want it, here is the diagram with full bridge rectifier.
    I used 1 Amp. Shottky diode 1N5819 for D1, inexpensive and readily available. Its low forward drop foltage is less than 0.1V for the current that flow through it, this enables to charge C1 to the highest voltage possible.
    C1 stores energy that will be used during measure phase, it must provide 5V at the end of this stage. Assuming typical values for GP2D12 (I=35mA, conversion time=50ms) and an initial 7.5V across C1, its value is C = I * dT / dV = 35 * 50 / (7.5-5) = 700 µF. Small margin with 1000 µF...
    U1 is a low drop out 5V regulator in TO92 case. I used a Telcom/Microchip TC55RP5000, but other regulators will probably work, such as STMicroelectronics L4931-50. Standard regulators such as 78L05 will NOT work because they require more than 7V at input to get a 5V output. Take care with some low drop regulators such as LM2931 that require more than 25 mA when powered at 1V. With RCX current limitation, this hog eats all energy. (I was caught with this one...)
    Q1 switches power on and off for GP2D12. At 35 mA current, I originally used a plain-vanilla BC548. My sensor began to work with it, but exhibited strange behavior. Looking to GP2D12 power supply I then discovered 2V dips ! I then looked at GP2D12 consumption and discovered that it was pulsed (220mA pulses 1/8th of time, supperposed to a 8mA constant current. See oscilloscope captures here). At such a current, BC548 has a low gain, and since I couldn't lower base resistor R1 (main current drain during capacitor charge) I used a high performance Zetex transistor, ZTX718 that offers high gain at high current (other similar devices can work!).
    C2 stabilizes U1 and helps absorb peaks of current. A low ESR version would be better (see "grass" on 5V output when GP2D12 works).

Extending the MAX6959 LED Display-Driver Keyscan from 8-Keys to 12-Keys BAV70

The circuit is shown in the image. Each key requires a dual diode (such as the low-cost common-cathode BAV70 in SOT-23), which pulls both INPUT1 and INPUT2 low when the switch is pressed.

 Each of the four extension keys is wired to simulate a dual key press for the two keys on each of the four LED cathode drive outputs, DIG0/SEG0 through DIG3/SEG3. With this connection, each key pair is always scanned and debounced at the same time. Extra keys that simulate a dual key press of keys scanned by different LED cathode drive outputs will be unreliable. Because the keyscan is performed sequentially, two keys at a time, the extra key could miss the debounce cycle for one LED cathode drive, yet be correctly debounced by the other. This dual key press would then appear as two sequential key presses, not as a dual key press. This wouldn't happen with the recommended connection scheme because each key pair representing a dual key is debounced together.

User Interface - Lcd Driver Based On The HT1621 Controller

Application Note Abstract This Application Note describes implementation of a liquid crystal Display (LCD) driver based on the widely available HOLTEK HT1621 LCD Controller Methods and algorithms of Display control are described and an API library is provided. The LCD used in this example was a customer’s custom part. The proposed algorithms CAN be easily adapted to any custom LCD panel connected to the controller. Introduction LCDs are widely used as data Display devices in embedded systems. Among the features that have made LCDs popular are low price, low power dissipation, lightweight, durability, reliability, and broad support by dedicated ICs for Communication with Microcontrollers A good example of an LCD Driver is the Hitachi character LCD Driver HD44780, the industry standard. This dot-matrix LCD Controller is supported by PSoC APIs. It is useful in applications that permit alphanumeric data Display However, specialized Displays are often needed. Specialized Displays keep end- product prices low, simplify the Interface between the Microcontroller and LCD Driver and decrease weight and size parameters. Examples of specialized Displays include Clocks calculators, telephones, and home and industrial appliances. This implementation is based on one of these dedicated drivers, the HT1621. This Application Note addresses the proposed implementation in two parts: ƒ General Description ƒ LCD Driver Implementation General Description The HT1621 driver is a 128-segment (32x4), multi-functional LCD Driver with memory mapping. The software configuration feature of HT1621 makes it suitable for many LCD applications, including LCD modules and Display subsystems. Only three or four connections are required for interfacing between the host controller and the HT1621. A structural schematic of the Display system is shown in Figure 1. This structure requires few external components and uses only three Interface connections. The system consists of the PSoC, HT1621 controller, and an LCD panel. The HT1621 besides its primary function as an LCD controller, has peripherals including the watchdog Timer time base generator and the Tone frequency generator. For more information about these features, refer to the HT1621 data sheet. Note that the controller has an on-chip RC Oscillator (256 kHz) for controlling the LCD and peripherals. This General Description focuses on the components and functions of the HT1621 driver that relate directly to the LCD: ƒ Display Memory RAM ƒ LCD Driver in HT1621 ƒ Command Format ƒ Interfacing with HT1621

Circuit Power Amplifier OTL 50W by 2N3055

If you are seeking power Amplifier at loud good sound , durable and economize. I begs for to advise Circuit Power Amplifier OTL 50Watt by 2N3055 , because of use the equipment that seek good easy and build not difficult with. Many you who tell amp OTL the sound is not good. Me chest edge that be not the loud sound is excellent. Then like to use general ( in the past ) although in contain divide still have use. I like it fining decorates the circuit. Just you feed power supply 50V 2A also the work has already and a loudspeaker should use 8ohm 12 inc. sizes. Besides still model PCB for the convenience of friends. Request have fun Power Amplifier OTL 50Watt , please sir.

TIP122 Connection Diagram

TIP122



Speed control of permanent-magnet (PM) dc motors with the aid of optical or dc tachometers is generally inconvenient and difficult, particularly on motors with integral gearboxes. The high-speed shaft of the motor that drives the gearbox isn't always accessible and the speed of the geared-down shaft often is too low for tachometers. Described here is a single-supply regulating speed-control circuit that doesn't require a tachometer. It keeps the motor torque high under load by using positive feedback to compensate for the drop caused by armature resistance. In unregulated variable-speed PM dc motor systems, the drop in speed under load is particularly pronounced at low motor-supply voltages. The positive feedback generates a negative resistance that compensates for the nonlinear effects caused by armature resistance. It thereby ensures that the speed-control input voltage (V_i) linearly controls the speed of the motor. Armature resistance compensation is achieved if:

             R_S= R_A/[gain(R₃) / (R₃ + R₄)] - 1

The divider action of R3 and R4 together with the gain reduces the value required for R_s to minimize the power dissipation. C1 and R4 dampen the positive-feedback signal's response time, but they also form a low-pass filter and attenuate the motor current noise fed to the A2 input. The maximum output voltage swing from A2 is approximately V_CC-2 V, and there is a 1.2-V V_be loss by T1. This implies that the supply voltage (V_cc) should be about 5 V above the maximum desired motor voltage in order to allow for extra output drive to the motor under heavy load conditions. A reason-able choice for R_s is approximately R_A/10, and the gain of A2 should be trimmed with RV2 to ensure that the motor's speed does not drop when loaded.

An Arduino Compatible - CP2102

Standard Arduino boards use FTDI’s FT232RL to interface with computer’s USB port. Since FT232R is just a USB to UART converter, it is possible to build an Arduino compatible USB interface using other USB to UART chips.

One such alternative is Silicon Labs‘ CP2102. I particularly like this USB to UART transceiver because very few extra components are required for it to work. As an added benefit, this chip is also cheaper than the ubiquitous FT232R. Of course, there are also a few trade offs. First of all, CP2102 does not provide a bit bang interface (the X3 pins on the Arduino board on the other hand can be used for bit bang operations, but the X3 pins are not soldered with header pins by default and thus for the average users no bit bang support should not be an issue). Secondly, CP2102 does not have the configurable general purpose I/O pins to drive the TX/RX LEDs. There are other minor differences as well (for instance the maximum transmission speed for FT232R is 3Mbps while CP2102 tops at 1Mbps. Both chips are more than adequate for the maximum 115,200 baud rate supported in Arduino environment), but they do not affect the performance in our application of interfacing with Arduino.

Here is the schematics for using CP2102 with ATmega328p (the circuit below is compatible with the Arduino IDE):

if you compare the above circuit with the official Arduino Duemilanove board you will see that the interfacing portions (RXD, TXD and TDR) are virtually identical.
Since CP2102 comes only in QFN-28 packaging, some people might find it slightly harder to deal with than TSSOP. Using the prototyping method I mentioned a few months back though, it is fairly straightforward to use the chip on a standard perf-board nevertheless. No special tools or stencils are needed. The following picture shows the USB to UART converter portion of the Arduino, which can be used to replace the FT232 break out board. I chose to break out the converter so that I could use it in other projects that require serial connections.



If you are running Linux, you do not need any third-party device drivers. All recent Linux kernels support CP210x via the usbserial kernel module. Once connected, you should be able to use dmesg and see these messages:

    [ 8333.572512] usb 8-2: new full speed USB device using uhci_hcd and address 3
    [ 8333.744748] usb 8-2: configuration #1 chosen from 1 choice
    [ 8333.785114] usbcore: registered new interface driver usbserial
    [ 8333.785161] USB Serial support registered for generic
    [ 8333.785221] usbcore: registered new interface driver usbserial_generic
    [ 8333.785222] usbserial: USB Serial Driver core
    [ 8333.792419] USB Serial support registered for cp210x
    [ 8333.792460] cp210x 8-2:1.0: cp210x converter detected
    [ 8333.920011] usb 8-2: reset full speed USB device using uhci_hcd and address 3
    [ 8334.076745] usb 8-2: cp210x converter now attached to ttyUSB0
    [ 8334.076760] usbcore: registered new interface driver cp210x
    [ 8334.076762] cp210x: v0.09:Silicon Labs CP210x RS232 serial adaptor driver

If you are running Windows, you will need to install the royalty-free driver from Silicon Labs directly.

Under Linux, CP210x shows up as a a ttyUSB device. You can use the Arduino IDE to program your ATmega328p’s just as you would with an official Arduino. Serial communication via the serial monitor works the same way as well. Like the official Arduino, the above circuit also automatically resets whenever you upload a program.
 

2N2907A Small Signal PNP Transistors

2N2907A

Small Signal PNP Transistors

This circuit shows a synchronous-rectifier-based ac/dc converter which has high accuracy up to about 2.5 MHz. To calibrate, apply a 1- to 2-MHz 1-V pp sine wave and adjust the delay compensation so that bridge switching occurs when the sine crosses zero. Next, adjust both skew compensation pots for minimum aberrations in the ac output signal. Finally, adjust the gain trim for a dc output that corresponds to the ac input.

Diagram Block IC TDA7377

The TDA7377 is a new technology class AB car radio amplifier able to work either in DUAL BRIDGE or QUAD SINGLE ENDED configuration.



The exclusive fully complementary structure of the output stage and the internally fixed gain guarantees the highest possible power performances with extremely reduced component count. The on-board clip detector simplifies gain compression operation. The fault diagnostics makes it possible to detect mistakes during car radio set assembly and wiring in the car.

The stand-by can be easily activated by means of a CMOS level applied to pin 7 through a RC filter. Under stand-by condition the device is turned off completely (supply current = 1µA typ.; output attenuation= 80dB min.). Every ON/OFF operation is virtually pop free. Furthemore, at turn-on the device stays in muting condition for a time determined by the value assigned to the SVR capacitor.

While in muting the device outputs becomes insensitive to any kinds of signal that may be present at the input terminals. In other words every transient coming from previous stages produces no unplesantacoustic effect to the speakers.