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Radxa ROCK Pi 4B   2GB RAM+ Heatsink For Sale

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Radxa ROCK Pi 4B   2GB RAM+ Heatsink:
$39.00

Used Radxa ROCK Pi 4B 2GB RAM + Heatsink. Tested working, has some marks from use.

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Radxa Rock Pi 4 SE 4GB RAM

$110.46

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RK3399 RADXA ROCK Pi 4 Dedicated V1.6 Version Development Board Steering1264

$25.44

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RK3399 RADXA ROCK Pi 4 Dedicated V1.6 Version Development Board R5T58328

$24.38

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Popular Tutorials

Alarms and Indicator Circuit diagrams

• Power supply failure alarm
• Theft preventer alarm
• Rain Alarm
• A simple electronic buzzer
• Water Level Indicator with alarm

Audio electronic circuits list

• Stereo Channel Selector
• Low cost intercom using transistors
• Infrared Head Phones
• Use the CD-ROM drive as a audio CD player without the computer
• Audio Visual Indicator for Telephones
• Ultrasonic pest repellent

Circuits for Cars/Motorcycles

• Charge Monitor for 12V lead acid battery.
• Wiper Speed Control
• Dome Light Dimmer for Cars
• Car anti theft wireless alarm.

Computer/PC Hardware Circuits :

• Control electrical appliances using PC
• Simple Analog to Digital Converter
• PC based Frequency Meter
• 7 segment rolling display using PC

Design Ideas :

• Soft ON/OFF switch

Fun/Games Circuits :

• Electronic Scoring Game
• JAM(Just A Minute) Circuit
• Flashy Christmas Lights
• TV remote control blocker

Signal/Sequence/Misc. Generators :

• Simple IF Signal Generator

Home/Garden related Circuits :

• Ultrasonic Pest Repeller
• Programmable Digital Code Lock
• Pot plant water tester

Lights & LED Circuits :

• Light Flasher (blinking lights)
• Automatic Dual output Display
• Emergency Light
• Automatic Room Lights
• Running Message Display

Motor Circuits :

• Automatic Speed Controller for fans & Coolers
• Soft Button type Motor Direction Controller
• Super simple stepper motor controller
• Discrete component motor direction controller

Music related Circuits :

• Digital Volume Control
• 5 band graphic equalizer

< Oscillator Circuits :

• Simple variable frequency oscillator
• Sawtooth wave generator

Power Supply (PS) Circuit diagrams :

• Negative supply from single positive supply
• Self switching Power Supply
• Ultra low drop linear voltage regulator

Radio,transmitter,receiver circuits :

• Car anti theft wireless alarm.
• Long range FM transmitter
• Remote control using VHF modules
• 40 meter Direct Conversion Receiver

Remote Control Circuit diagrams :

• Remote control using VHF modules
• Remote control using telephone
• A simple Remote control Tester
• Clap Activated Remote
• Radio Remote Control using DTMF
• Ultrasonic switch

Robotics related Circuits :

• Magnetic proximity sensors
• Color Sensor
• Super simple stepper motor controller

Sensors :

• Magnetic proximity sensors
• Dew sensor
• Color Sensor
• Metal Detector
• Optical toggle switch using a single Chip

Telephone Circuit diagrams :

• Telephone Ringer using 556 dual timers
• Two line intercom plus a telephone changeover switch
• Telephone line based audio muting and light on circuit
• Having secrecy in parallel telephones
• Telephone call meter using calculator & COB

Test & Measurement Circuits :

• High Resistance Voltmeter
• A simple Remote control Tester
• Contactless Mains Voltage Indicator
• Zener Diode Tester