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.

AD603AR low noise, voltage-controlled amplifier

The AD603AR is a low noise, voltage-controlled amplifier for use in RF and IF AGC systems. The AD603AR provides accurate, pin selectable gains of –11 dB to +31 dB with a bandwidth of 90 MHz or +9 dB to +51 dB with a bandwidth of 9 MHz. Any intermediate gain range may be arranged using one external resistor. The input referred noise spectral density is only 1.3 nV/ÖHz and power consumption is 125 mW at the recommended ±5 V supplies. The applications of the AD603AR include RF/IF AGC Amplifier, Video Gain Control, A/D Range Extension, Signal Measurement.

AD603AR absolute maximum ratings: (1)Supply Voltage ±VS: ±7.5 V; (2)Internal Voltage VINP (Pin 3): ±2 V Continuous, ±VS for 10 ms, GPOS, GNEG (Pins 1, 2): ±VS; (3)Internal Power Dissipation: 400 mW; (4)Operating Temperature Range: –40℃ to +85℃; (5)Storage Temperature Range: –65℃ to +150℃; (6)Lead Temperature Range (Soldering 60 sec): +300℃.

AD603AR features: (1)"Linear in dB" Gain Control; (2)Pin Programmable Gain Ranges: -1 dB to +31 dB with 90 MHz Bandwidth, +9 dB to +51 dB with 9 MHz Bandwidth; (3)Any Intermediate Range, e.g., -1 dB to +41 dB with 30 MHz Bandwidth; (4)Bandwidth Independent of Variable Gain; (5)1.3 nV√Hz Input Noise Spectral Density; (6)±0.5 dB Typical Gain Accuracy; (7)MIL-STD-883 Compliant and DESC Versions Available.

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.

pulse signal interfaces EPC1PC8

The pulse signal examined is a driving signal of the power, used in the propulsion power to support, the drive current is usually several mA to several numerous mA, adopt the open-collector gate OC The form is exported, it is usually 12 – 30 V signal. For compatible many kinds of signal levels, and can isolate power type signal and ordinary base band level signal, realize better electromagnetic compatibility, this system adopts the photoelectric coupler as signal isolation and interface device of level switch.

TLP121 is the photoelectric coupler that Toshiba produced, isolates impedance as M grade, its drive current of forward direction IF Maximum 20 mA, rear end switch open and make time ‘s s grade, can respond to the request that the error in emasurement of this system pair is not greater than 1 ms. The input interface resistance is set as the adjustable resistance, can adapt to different input voltages.

The pulse signal interface circuit is shown as in Fig Straight line and loop of pulse signal are connected to the forward end 1, 3 pins of TLP121 in Fig of the photosensitive resister ,Rear end 4, 6 pins of TLP121 in Fig Adopt 5V power in the board to pull upward, sends and deals with FPGA to the interface after having a facelift through the Schmidt circuit 74HC14. When the pulse signal is effective, photosensitive resister forward end have electric current flow through, interface circuit export the intersection of high level and ” the 1 ” ; When pulse signal invalid, interface circuit export the intersection of low level and ” the 0 ” .

interface treatment FPGA

Because need to gauge pulse signals of No. 80, it is unable to meet concurrent processing’s demands to adopt the one-chip computer, so choose FPGA and finish the impulse sampling function. Interface deal with FPGA adopt the intersection of Altera and FLEX10K50 of Company, working primary frequency is 6 MHz, the storage chip adopts EPC1PC8.
Its main function has three parts: Frequency demultiplication timer, sampled data buffer, peripheral control logic. FPGA carries on the frequency demultiplication to the main clock, forms cycle as the clock signal of 1 ms. FPGA every ms finishes running side by side and gathers the pulse signals of No. 80 once, leaves the data in the register, send out the interrupt signal to the one-chip computer at the same time, notify the one-chip computer and initiate the data to move, and the time counter within the one-chip computer increases by oneself. The sampled data buffers the module and is used for latching the pulse signals of No. 80 to the internal register at the same time, the one-chip computers every ms all read once. Peripheral control logic is used in the decipher of every control signal of periphery of the one-chip computer, including control register, every chip control the signal interpretation, and the realization of other auxiliary functions.

INA128, Adding -9V offset with reference pin BAV99

There is a bipolar (-10V/+10V) ADC on my circuit. And want to measure 0V to 5V signal with high empedance circuitry. To not loose ADC resolution I want to add a negative offset in INA128 circuit without using second amplifier. (0V to 5V  input;  -9V to 8.5V output) Theroticaly and experimentaly (using TINA-TI)  applying -9V to INA128 reference input solve my problem. Input and output voltage seems to be within specified limits but what about internal node voltages.

According to my calculation; when input is 5V and output is 8.5V,  A2 output node should be 11.25V.  But it seems difficult the reach this level with 12V supply. (Is it RRO)

Could you please clearify and make me sure for these ?

1.) Reference input is just intended for applying small offset nulling voltages or can I use it to apply higher offset ?

2. ) Using -9V offset is adequate for INA128 ? If yes how does it effect the CMRR ?

3.) Using 15V positive supply for INA128 allows me to apply -9V offset to reference pin if 12V supply is not enough?
a

( Diodes are BAV199 but not found in TINA-TI library so I used BAV99 instead. )

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

Using DS3902 in Low Cost Optical Modules and Serial EEPROM AT24C02

The two variable resistors in DS3902 are used to set bias and modulation currents. The settings are done through I2C* interface. Some modules may require additional EEPROM. This is typically used for serial ID information, and new modules may need to include this feature. DS3902 has programmable address, therefore connecting it to a single I2C bus line (with other devices) without any additional components.

Figure 2 shows connection details for using DS3902 and a serial EEPROM (ATmel AT24C02) on a common I2C interface. Also Figure 2 illustrates connections to a laser driver.

 The DS3902's default address is A2h (Add_sel = 0). If an address different from A2h is required, Add_sel will be pulled high. Register 00h content is the device address when Add_sel = 1. In the above schematic AT24C02 is configured for A0h address, (A0 = A1 = A2 = 0).

The WP (write-protect) pin connects to ground using a link, allowing R/W access to memory locations. Once the memory is programmed, the WP pin can be pulled high through LK1, to prevent accidental write. DS3902 has S/W protection scheme, whereby access to memory is only possible with password.

The choice of laser driver depends on the specific application and there are a number of Maxim laser drivers to choose from.

CA3046 VCA

Using discrete transistors from a transistor array, this circuit avoids an OTA altogether. It uses one transistor as a Gilbert multiplier to predistort the signal, so that a larger signal can be fed into the circuit. The circuit is based on the one described in Modulus issue 5, that was provided by Chris Crosskey.
I have modfied it with a trimmer to adjust the DC offset and adjusted the input sensitivity and output gain to give some headroom and unity gain. This VCA has a linear response. A diode has been added on the control input, to block out negative voltages, which cause DC on the output. Because of the diode, the control caracreristics is unlinear below 1 volt.
The predistortion really works in this circuit. The distortion stays low up to a point where it suddenly increases dramatically. With the chosen resistor values, that point is well above normal signal levels.
Noise figures for this circuit is comparable to the SSM2024 and the LM13600 but signal bleedthrough is not as good. On the other hand, CV bleedthrough is lower than the LM13600, with proper trimming.


CA3046

LM317T Variable Voltage Regulator

The LM317T is a adjustable 3 terminal positive voltage regulator capable of supplying in excess of 1.5 amps over an output range of 1.25 to 37 volts. The device also has built in current limiting and thermal shutdown which makes it essentially blow-out proof.

Output voltage is set by two resistors R1 and R2 connected as shown below. The voltage across R1 is a constant 1.25 volts and the adjustment terminal current is less than 100uA. The output voltage can be closely approximated from Vout=1.25 * (1+(R2/R1)) which ignores the adjustment terminal current but will be close if the current through R1 and R2 is many times greater. A minimum load of about 10mA is required, so the value for R1 can be selected to drop 1.25 volts at 10mA or 120 ohms. Something less than 120 ohms can be used to insure the minimum current is greater than 10mA. The example below shows a LM317 used as 13.6 volt regulator. The 988 ohm resistor for R2 can be obtained with a standard 910 and 75 ohm in series.

When power is shut off to the regulator the output voltage should fall faster than the input. In case it doesn't, a diode can be connected across the input/output terminals to protect the regulator from possible reverse voltages. A 1uF tantalum or 25uF electrolytic capacitor across the output improves transient response and a small 0.1uF tantalum capacitor is recommended across the input if the regulator is located an appreciable distance from the power supply filter. The power transformer should be large enough so that the regulator input voltage remains 3 volts above the output at full load, or 16.6 volts for a 13.6 volt output.

Wideband Sense & Heater Control ADC muxing 74HC4052

 The dual 4 to 1 line mux U4 (74HC4052) allows two groups of four signals to be sensed by the microcontroller's two ADC input lines ADC0 and ADC1.

Wideband signals Vsx5, Ih, Vsx1, IpSense, DACV & Cal (VGND) voltages are sensed as well as H- via filtering provided by R112 and C103. also shown here is the H+ sense signal but it is not selected by the mux, but rather passed directly to the microcontroller via filter components R111 and C102.

Analogue user channel 1 USR1 (see Y5 connector input below) is also sensed by this mux.

Variable Frequency PWM Circuit IRFP064N

R1,R6,R11 = 10K
R2,R9 = 1K8
R3 = 100 ohm
R4,R8 = 1K
R5 = 22K
R7 = 1M
*R10 = 0.003 ohm
R12 = 3K9
R13 = 100K
R14 = 10 ohm/1 Watt
P1 = 20K (Frequency adjust)
P2 = 10K (Duty Cycle)
P3 = 1K (Current Limiting)
C1 = 1000uF, 64V
C2 = 10nF, polyester
C3 = 100uF, 64V
C4 = 22nF
C5 = 47uF, 35V
D1,D2 = 1N4004
U1 = LM7810, volt regulator
U2 = LM324, Op-amp
Q1 = IRFP064N , IRFZ44, etc. MOSFet

FM Stereo decoder using TDA7388

A very simple with a compact design FM stereo decoder schematic circuit can be designed using the TDA7388 IC manufactured by ST Microelectronics .
The TDA7338 is a monolithic integrated stereo decoder with noise blanking for FM car radio applications.
With the used BICMOS technique, the 19KHz Notch Filter, the PLL Filter and Phase Filter is realized on the chip with a Switched Capacitor concept.
The TDA7338 stereo decoder contains all necessary functions for processing the MPX signal.
The only external component needed for the PLL is the ceramic resonator for the oscillator which runs at 456kHz.

The pilot detector output is designed as an open collector output, therefore an external pull up resistor is needed. To force the decoder to "MONO" Pin 19 has to be clamped to a voltage below 0.8V.
Selecting VCO-OFF (Pin 7 to GND) the VCO is switched off and the SB and HCC are disabled.
This TDA7338 receiver circuit needs to be powered by a 9 volts DC power supply .