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Indicators and testers
Continuity Tester
tn_cps110.jpg
Two range tester will buzz up to 3 ohm LO range, and 185 ohm HI range. You can set your own ranges by changing resistor values connected to the LM324 quad op-amp. Full circuit description, PCB and components supplied. A Continuity Tester is one of the most useful pieces of test equipment to have. It is used for testing the electrical path (continuity) between two points. It is more useful and efficient than using a multimeter to do the same job. This Continuity Tester has an audible output so you can keep your eyes on the probe tips while working. In addition it will only 'buzz' through a specified resistance or less. Above this value the tester will not make any sound. A switch is provided to allow this resistance to be varied. The Tester runs from a 9V battery (not supplied). The tester will 'buzz' up to about 2.8 ohm for the LO position and up to 185ohm for the HI position (this may vary slightly due to component tolerances). PCB size: 51mm x 38mm (2" x 1.5"). (CPS110)
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  Kit - Basic Soldering Required  
  CPS110  
  8  
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General Purpose 3 1/2 digit panel meter
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Voltage is the most frequently measured electrical quantity. Full instructions included in this kit to make your own 3 1/2 digit panel meter for any standard or non standard range. Can also measure current and resistance. Many components located underneath the LCD and 7106 on the PCB. Double sided board. PCB size: 53mm x 56mm 2.09” x 2.20” Working voltage 9V DC. (CPS127)
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  Kit - Basic Soldering Required  
  CPS127  
  6  
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Introduction to LCDs kit
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The aim of this kit is to show how to use a 16x2 alphanumeric Liquid Crystal Display (LCD) with a PC. First we show how to connect it to the parallel port and echo and handle keyboard input. Then we show how to use the LCD to display temperature from a DS1620 Digital Thermometer / Thermostat chip and set the HI & LO triggerpoints in it. All C source code is provided. PCB size: 3 1/4"x2 3/4".
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  Kit - Basic Soldering Required  
  CPS134  
  3  
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Wind Speed Meter Kit
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"This is a Kit of the no-moving parts Wind Speed Meter. We have redrawn the PCB so that the 2x16 LCD fits on top of the main PCB. The schematics have been redrawn but we have kept the same Component Designators. An Off/on switch and input protection diode have been added. Ten mm nylon standoffs in each corner raise the PCB and allow the two switches S2 and S3 to come out. Also access to VR1 and VR2 is easy since both trimpots are mounted underneath the PCB. Access to test points with a CRO is also easy with this arrangement. We did not keep the In Circuit Programming header." (CPS168)
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  Kit - Basic Soldering Required  
  CPS168  
  4  
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LCD Temperature Meter kit (incl Box)
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Introduces 3 1/2 digit LCD and the very popular 7106 IC. This IC has been used in low-cost multimeters for over 13 years. We use it to measure temperature using an ordinary signal transistor as the sensor. Data sheets are provided as is a breadboard area so you can extend the circuit to build your own voltmeter, ammeter, resistance meter or extended-range temperature meter. Takes away the mystery of how multimeters work. Box provided. 9V battery operation.(CPS2)
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  Kit - Basic Soldering Required  
  CPS2  
  4  
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Logic Probe
tn_cps24.jpg
This is the most important piece of equipment for testing and measuring digital equipment. It is usually used in fault finding and testing but can also assist in design work and in finding out how digital equipment works. Switch for either TTL or CMOS. Modern design using a PUT. Includes detection circuit for very fast pulses. Gives visual (3 LED's) and audio (piezo buzzer) response.(CPS24)
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  Kit - Basic Soldering Required  
  CPS24  
  3  
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General 3 1/2 Digit Panel Meter (use 7106 IC)
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Make this general purpose 3 1/2 digit LCD panel meter into your own voltage or current meter or custom-make it to measure voltage input from a transducer. Full details are given in the documentation. Uses the very popular 7106 IC. The LCD section of the PCB may be cut off and mounted separately. Decimal Point selectable. Terminal strips input. Working voltage 9V DC.(CPS34)
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  Kit - Basic Soldering Required  
  CPS34  
  13  
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LED 3 1/2 digit panel meter kit
tn_cps61.jpg
Make this general design 3 1/2 digit LED panel meter into your own voltage or current meter. Or customize it to measure input from a transducer. Two PCB's allow low-profile end-on viewing. All instructions to assemble and operate meter are included. Meter can directly input an offset voltage, for example from a weighbridge, use non-standard voltage inputs, measure current or high voltages.(CPS61)
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  Kit - Basic Soldering Required  
  CPS61  
  5  
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Stereo VU Meter
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Simple, low cost stereo VU meter. Two LM3915 dot/bar display driver ICs used to drive 2 rows of 10 LEDs(14 green,6 red)in a moving bar display. Each row of LEDs spans a power range of 0-30 dB in ten 3-dB steps. This VU meter indicates 'peak music power' when used with audio amp. Ideal add-on for any amplifier kit. PCB size: 65mm x 42mm.(2.6" x 1.65") This VU meter is capable of monitoring and displaying power levels present at the speaker terminals of a stereo audio power amplifier. Levels are displayed in ten discrete steps. This meter is not designed to give an accurate display of the power levels. It is designed to give an approximate visual indication of the audio power output of each channel. For many situations-disco, parties- this is all which is required: the flashing LED's add atmosphere to the situation. No calibration required. The kit is constructed on single-sided printed circuit board. It contains two identical circuits, one for each channel of the amplifier.(CPS89)
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  Kit - Basic Soldering Required  
  CPS89  
  5  
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8 INPUT PROGRAMMABLE MESSAGEBOARD WITH LCD & SERIAL INTERFACE
Click here for specs, downloads, and more pictures.
NEW - LOWER PRICE!
Price was: $53.71

Features:
 
add an LCD display to any low-tech application and make it look high-tech !
replace up to 9 indicators or lamps by one single backlit LCD
recall messages simply by pressing a button
inputs accept dry contacts, open collectors and logic levels
no programming skills required !
store up to 9 sixteen-character messages in non-volatile EEPROM memory
4 operating modes:
  1): display the status of all inputs simultaneously
  2): display all active inputs
  3): display active input with highest priority
  4): display text messages in a 'tickertape'-fashion
a default message can be entered which is displayed when no inputs are active
messages can be transferred to the K8045 from any PC or terminal
message transfer software is available from www.velleman.be
wireless data transfer between PC/terminal and K8045 is possible with optional RX/TX433 modules
1 on-board pushbutton available for your application
(K8045)
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  Kit - Complex Soldering Required  
  K8045  
  2  
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LCD MINI MESSAGE BOARD
tn_mk157.jpg
Features:

miniature message board with 16 character 1 line LCD display
message scrolls from right to left with adjustable speed
applications: at exhibitions, for advertising, to greet visitors at the front door, as name tag, ...
46 character message memory
possibility to add pauses during scrolling
 

Specifications:

power supply: 2 AAA battery (not incl.)
dimensions: 3.9" x 1.5" x 1.3"
(MK157)
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  Kit - Basic Soldering Required  
  MK157  
  5  
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DIGITAL TACHOMETER
Click here for specs, downloads, and more pictures.
For cars or motorcycles with a petrol engine. May be used as a general purpose revolution counter.

Specifications:

range: 100 - 9900 revolutions/minute
2 digit display
easy calibration
power supply: 10 - 15V DC / 200mA
PCB dimensions: 3.2" x 1.8" + 3.2" x 2.4"
front panel dimensions: 2.8" x 3.5"

Extra Info
   - Hints

See special instructions in manual for use with electronic ignition.
(K2625)
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  Kit - Basic Soldering Required  
  K2625  
  6  
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GENERAL PURPOSE TEMPERATURE SENSOR
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Applications

measure indoor and outdoor temperatures, control heating and/or cooling of rooms, equipment, etc... Monitor temperatures in processes, put a temperature readout on your website, check your pools temperature, ...

Specifications:

range: -20° ~ +70°C
output: 0 ~ 20mA current loop
output voltage compliance: 10V
accuracy: 2° full range
one single adjustment
3-wire system: GND, +V and OUT
power supply: 12VDC for 0 ~ 5V OUT / 15VDC for 0 ~ 10V OUT
current consumption: 30mA max.
dimensions: 55 x 35 x 15mm (2.2" x 1.4" x 0.6") 
(K8067)

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  Kit - Basic Soldering Required  
  K8067  
  4  
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UNIVERSAL TEMPERATURE SENSOR
tn_vm132.jpg
NEW - LOWER PRICE!
Price was: $23.40

Features:

applications:
measure indoor and outdoor temperatures
monitor heating and/or cooling of rooms, equipment, etc...
monitor temperatures in processes
put a temperature readout on your website
check your pools temperature...

Specifications:

range: -20°C (-4°F)... +70°C (+158°F)
output: 0..20mA current loop
output voltage compliance: 10V
one single adjustment
3-wire system (GND, +V and OUT)
power supply:
12VDC for 0..5V OUT
15VDC for 0..10V OUT
current consumption: 30mA max.
dimensions: 55x35x15mm /2.17" x 1.38" x 0.59"
(VM132)
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  Assembled and Tested  
  VM132  
  3  
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Dual Amplifier as a kit
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Often you want a simple amplifier to amplify or annunciate the signal you are feeding into a data acquisition system. For example you have a signal from a temperature sensor that is providing 10mV/deg but you are only operating over 0-40 degrees giving an effective span of 0 to 0.4V. Your data acquisition system accepts a signal of 0 to 10V so you would like to amplify your signal by 10 to get better resolution. Or you may have a 48V battery that you wish to monitor with a data acquisition system that has a 0 to 5V input range. You could use a simple voltage divider but the input impedance of the data acquisition is only a few kilo ohm. Or you may have a 4-20mA signal you wish to convert to 2 to 10V or 1 to 5V This Dual DC amplifier provides a solution to these problems and more

The dual DC amplifier circuit consists of two non inverting amplifiers (OP1 and OP2) with a voltage divider at the input. Each amplifier is identical in design and is issued with one 50K potentiometer. Whether the circuit amplifies or reduces the amplitude of the signal depends on where the 50K potentiometer is placed on the circuit. A simple jumper allows the circuit to operate off a 9 to 24V supply for amplification of unipolar signals or it can be powered by a +/-9 to 15V supply for amplification of bipolar signals.
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  Kit - Basic Soldering Required  
  KIT-200  
  2  
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WATER ALARM
Click here for specs, downloads, and more pictures.
Gives alarm sound when water is detected. Incorporated alarm buzzer. Water sensor can be placed at a distance by cutting the board and using wires to connect the sensor.

Specifications:

power supply: 9V battery (not incl.)
dimensions: 1.8" x 2.8" 
(MK108)
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  Kit - Basic Soldering Required  
  MK108  
  3  
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CABLE POLARITY CHECKER
tn_mk132.jpg
Check cables for continuity and identify individual wires. Ideal for speaker cable polarity checking. LED indication for open circuit, shorts and correct or wrong polarity. Pushbutton operation with auto power off.

Specifications:

low power consumption: 10mA max.
power supply: 9V battery operated (not incl.)
dimensions:
main board: 2.2" x 1.6" x 1.3"
remote board: 1.6" x 0.3" 
(MK132)
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  Kit - Basic Soldering Required  
  MK132  
  10  
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IR REMOTE CHECKER
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 (Out of Stock)NEW - LOWER PRICE!
Price was: $5.56

The easy way to check your IR remote for proper operation. Simple operation : point the remote at the sensor and push any button. 4 flashing LEDs indicate remote operation.

Specifications:

low power consumption
power supply: 9V battery (not incl.)
dimensions: 2.2" x 1.2" x 1.3" 
(MK137)
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  Kit - Basic Soldering Required  
  MK137  
  0  
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PARKING RADAR
Click here for specs, downloads, and more pictures.
NEW - LOWER PRICE!
Price was: $36.26

If you have problems parking then this kit is for you. Using (ultrasonic) sound waves, whose frequency is beyond our range of hearing, we can "measure" a distance. Consequently, a sensor mounted at the back of the car can give an indication of the distance between your car and the car parked behind you or other obstacles (only at the same height as the sensor). When the preset minimum distance is crossed, an audible signal is generated. (K3502)
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  Kit - Basic Soldering Required  
  K3502  
  2  
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FROST INDICATOR
Click here for specs, downloads, and more pictures.
Drive more safely in freezing weather. This kit uses a flashing LED to indicate a road temperature close to freezing point ; below that point the LED is on continuously. A reliable temperature sensor with mounting stud is included. 

Specifications
power supply: 10 - 15V DC / 25mA
PCB dimensions: 2.2" x 1.7"
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  Kit - Basic Soldering Required  
  K2644  
  2  
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METAL DETECTOR KIT
Click here for specs, downloads, and more pictures.
To come up against an electric cable while drilling a hole in a wall can have catastrophic consequences. Likewise, drilling into gas, water pipes or central heating pipes can be extremely hazardous. With a handy metal detector it can now be determined beforehand whether there are metal objects to be found in a wall, ceiling or floor. An LED indicates if a metal object is in the vicinity. If an audio signal is also desired, space has been provided on the PCB for buzzer type SV4/12-S to be connected. The PCB has been specially constructed to fit entirely into to the separately available box type G407.

Specifications:

metal detecting distance adjustable: up to 3.15"
power supply: 9V battery (not incl.)
LED indication (optional buzzer SV4/12-S)
dimensions: 2.2" x 2.5"
recommended housing: G407
(K7102)
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  Kit - Basic Soldering Required  
  K7102  
  8  
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Telephone Ring Detector with Relay Output (Kit)
tn_k8086.jpg
NEW - LOWER PRICE!
Price was: $28.34

Features:
  • Simply connect in parallel with phone line
  • Powerful LED flashes when phone rings
  • The unit will feature a relay output if connected to a 12VDC power supply
  • Relay output: continuous or on/off to the rhythm of ringing of the telephone
  • Complete with enclosure
  • Great for noisy environments, for the hearing impaired, as addional ringer, to replace existing ringer, ...
  • Accepts standard adaptor & telephone plug
  • Includes:
    • Attractive enclosure
    • Adhesive strips for easy fixing
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  Kit - Basic Soldering Required  
  K8086  
  5  
Quantity:  

TELEPHONE RINGER WITH BUZZER AND LED
Click here for specs, downloads, and more pictures.
Features:

accepts standard telephone plug
simply connect in parallel with phone line
no power supply necessary!
buzzer sounds and powerful led flashes when phone rings
great for noisy environments, for the hearing impaired, as additional ringer, to replace existing ringer,...
includes:
attractive enclosure
adhesive strips for easy fixing

Specifications:

10.000 mcd led !
connects to PSTN line
RJ11 connector
consumption: 10mA max.
dimensions: 80 x 55 x 35mm
(K8087)
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  Kit - Basic Soldering Required  
  K8087  
  4  
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TELEPHONE RING DETECTOR WITH RELAY OUTPUT (Assembled)
tn_vm144.jpg
NEW - LOWER PRICE!
Price was: $45.79

Features:
  • simply connect in parallel with phone line
  • powerful led flashes when phone rings
  • the unit will feature a relay output if connected to a 12VDC power supply
  • relay output: continuous or on/off to the rhythm of ringing of the telephone
  • complete with enclosure
  • great for noisy environments, for the hearing impaired, as addional ringer, to replace existing ringer, ...
  • accepts standard adaptor & telephone plug

Specifications:

  • 10.000 mcd led !
  • connects to PSTN line
  • RJ11 connector
  • supply: 12VDC/100mA adapter (Ex. PS1203)
  • output Contact (NO): 1A max.
  • dimensions: 80x55x35mm / 3,15 x 2,16 x 1,37"
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  Assembled and Tested  
  VM144  
  5  
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Telephone Ringer / Flasher
tn_telri.jpg
Description: Add an extra ringer to your phone.

Features:

  • 3 operation modes: flasher only / flasher + soft buzzer / flasher + Hard buzzer
  • Easy installation, just plug it in
  • No battery required
  • Wall mounting is possible
  • Only suitable for use with PSTN telephone lines
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  Assembled and Tested  
  TELRI  
  8  
Quantity:  

MULTIFUNCTION CAR INTERIOR ILLUMINATION
Click here for detailed specs.
If, like most of us, you do not have infrared eyesight, then at times
you have probably found yourself fumbling for the ignition switch or
seat belt in the dark. For people like you we have developed this
solution. With extra push button and battery protection.
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  Kit - Basic Soldering Required  
  K3500  
  4  
Quantity:  

SOUND TESTER GAME 10 LED
Click here for specs, downloads, and more pictures!
A basic sound power testing circuit that used for measuring of preliminary sound power and sound level which do not require precision or as a sound power testing game.

Specifications:

  • Power supply: 9VDC
  • Consumption : 20mA. (stand by), 50mA (working)
  • Adj. sensitivity : trimmer potentiometer
  • PCB dimensions : 2.29 x 1.11 in
  • Read More...
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  Kit - Basic Soldering Required  
  FK181  
  7  
Quantity:  

MXA069 DIGITAL UP-DOWN COUNTER 4 DIGIT WITH DRIVER
Click here for specs, downloads, and more pictures!
 (Out of Stock)Features:
  • It is a multi-purpose digital counter for counting traffic, people (head counts), motor-car or any other objects.
  • Power supply : 12VDC. With maximum 65mA.
  • Can be connected directly to big display not more than 9".
  • Maximum count from 0-9999.
  • Can be set for counting up or counting down.
  • Can preset the digit for resetting and restarting counting automatically and sending voltage to "OUT" point.
  • Can be connected to other board and extended counting to more than 9999 digits.
  • PCB dimension : 4.49x2.46 inches.
  • Read More...
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  Assembled and Tested  
  MXA069  
  0  
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FK137: PRIORITY TESTING GAME
Click here for specs, downloads, and more pictures!
Features:
  • It is the electronic circuit applied for decision making e.g. Games as seen on TV which the first player who presses the switch has the right to answer.
  • The light will show at only that player stage, every other players press the switch afterward
  • Power supply : 9 VDC.
  • PCB dimensions : 2.4" X 1.7"
  • Read More...
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  Kit - Basic Soldering Required  
  FK137  
  11  
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MXA009 DIGITAL UP / DOWN COUNTER 1 DIGIT ( with preset)
Click here for specs, downloads, and more pictures!
 (Out of Stock)Features:
  • Display dimensions : 1.59x1.29 inch.
  • PCB dimensions : 1.59x3.36 inch.
  • Power supply : 5 to 12 Vdc./max. 80 mA. at 12 Vdc.
  • Used for count unit.
  • For use with external display able select display type common anode or common cathode.
  • UP / DOWN counter selection.
  • Maximum input frequency (CI) : 15 KHz .
  • Start / Preset point counter.
  • A reset is available to reset the entire counter to zero.
  • Select the display of decimal point.
  • Read More...
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  Assembled and Tested  
  MXA009  
  0  
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FK904: RAINING ALARM
Click here for specs, downloads, and more pictures!
Features:
  • A very simple circuit with useful application, the device consists of a printed sensor to be put up in the open.
  • Generate a signal via an LED when wet.
  • Power supply : 9V.
  • PCB dimensions : 2.2” X 1.3” 
  • Read More...
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  Kit - Basic Soldering Required  
  FK904  
  3  
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FK935: BODY TEMPERATURE
Click here for specs, downloads, and more pictures!
Features:
  • An alarm sound circuit that measures the body temperature and warning for temperatures over 38° C
  • Power supply: 9 VDC.
  • Consumption: 38 mA. max.
  • PCB dimensions: 3.01 x 1.28 in.
  • Read More...
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  Kit - Basic Soldering Required  
  FK935  
  3  
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STEREO VU-METER 2 x 10 LEDS
Click here for specs, downloads, and more pictures!
Features:
  • Stereo VU meter with 2 x 10 LEDs (dot or bar indicator) and an adjustable input. 
  • Included in package :
    • 1 front panel suitable for horizontal or vertical mounting.
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  Kit - Basic Soldering Required  
  K4305  
  4  
Quantity:  

FK902: WATER LEVEL INDICATOR 3 LEVEL
Click here for specs, downloads, and more pictures!
 (Out of Stock)Features:
  • This circuit is designed to measure the water level in a pool or tank by using the led to show the water level.
  • Power supply : 6-9V.
  • PCB dimensions : 1.8” X 1.3”
  • Read More...
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  Kit - Basic Soldering Required  
  FK902  
  0  
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"Uh-oh" Battery Level Indicator Kit
Click here for specs, downloads &/or more pictures...
Description: Under-powering a digital device can sometimes have pretty nasty consequences. Brown-out conditions can cause memory to get written or overwritten in odd ways, can cause unexpected behavior in connected systems and just generally screw up your day. One way to avoid this is to keep an eye on your battery voltage and turn off the system before it gets too low (or plug it in). We've whipped up a little board to help you out with this situation: the "Uh-oh" battery level indicator.

At the heart of the "Uh-oh" board is the TL431ACLPG shunt regulator diode. The reference voltage can be adjusted by using the trimpot on board. When the battery connected to the board reaches that voltage, the shunt allows current to flow through the LED, alerting you to a low battery situation. In order to set the appropriate reference voltage, you can use the formula found in the schematic to calculate your desired resistance and set it using the trimpot and a multimeter measuring resistance across the provided test points.

This board comes as a "bag of parts" kit. All of the parts are through-hole and it shouldn't take long to solder together. The footprint of each part is clearly marked on the PCB to help you throw it together.

Note: It turns out you can replace the LED with the digital input of a 5V microcontroller. This allows you to write interrupts for low battery management. The output hovers just below 2V at "low" so it may work better on some micros than others. There is a picture in the "drill-down" page behind this one of this system implemented on an Arduino Uno.

Kit Includes: 
  • 'Uh-oh' Through-hole PCB
  • 10mm Diffused Green LED
  • JST Wire Assembly
  • TL431ACLPG IC
  • JST Right-Angle Connector
  • 10K Trimpot
  • 330 Ohm Resistor
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  Kit - Basic Soldering Required  
  KIT11087  
  15  
Quantity:  

KIT11087-TBA: "Uh-oh" Battery Level Indicator Kit (Assembled)
Click here for specs, downloads &/or more pictures...
Description: Under-powering a digital device can sometimes have pretty nasty consequences. Brown-out conditions can cause memory to get written or overwritten in odd ways, can cause unexpected behavior in connected systems and just generally screw up your day. One way to avoid this is to keep an eye on your battery voltage and turn off the system before it gets too low (or plug it in). We've whipped up a little board to help you out with this situation: the "Uh-oh" battery level indicator.

At the heart of the "Uh-oh" board is the TL431ACLPG shunt regulator diode. The reference voltage can be adjusted by using the trimpot on board. When the battery connected to the board reaches that voltage, the shunt allows current to flow through the LED, alerting you to a low battery situation. In order to set the appropriate reference voltage, you can use the formula found in the schematic to calculate your desired resistance and set it using the trimpot and a multimeter measuring resistance across the provided test points.

This kit comes completely assembled.

Note: It turns out you can replace the LED with the digital input of a 5V microcontroller. This allows you to write interrupts for low battery management. The output hovers just below 2V at "low" so it may work better on some micros than others. There is a picture in the "drill-down" page behind this one of this system implemented on an Arduino Uno.

Kit Includes: 
  • 'Uh-oh' Through-hole PCB
  • 10mm Diffused Green LED
  • JST Wire Assembly
  • TL431ACLPG IC
  • JST Right-Angle Connector
  • 10K Trimpot
  • 330 Ohm Resistor
NOTE: Please allow 24 hours for assembly!
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  Assembled and Tested  
  KIT11087-TBA  
  15  
Quantity: