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Fixing a Mouse Double Click Problems
2008-12-23 14:00:00
Have you ever experience a bad optical mouse? It went double click action whenever you did a single click action? At first, I try to Google for answer but none of them help. I’ve tried every combination of settings but the problem doesn’t go away. I really suspected there must be something wrong with the circuit. After I made a conclusion that it is a mechanical related issue (maybe the switch it self), I replace the switch from an old mouse available. Unfortunately the problem is still there. This is dangerous since you might drag a folder by accident and move it into another folder. This problem always happening to a first time touch-pad user with tapping function turned on. So next I’m thinking it maybe related to a noise in the circuit. So without any calculation, I try to salvage a capacitor that l can find from an old circuit board and solder it parallel to the switch. :-) Now it become “click and hold� for about 10 seconds. The capacitor value that I used t...
More About: Double , Click , Problems , Mouse

Simplest Intercom
2007-04-06 14:55:00
Using old phones Using your old phones, you could create personal "micro" telephone exchange as simple as above circuit. I manage to solder the test circuit less than a minute. Than connect the phone and test it. It works. So why 39 ohm? From Epanorama Dot Net, the correct value of the resistor should be a resistor that can limit the circuit current around 30mA total loop. The method is by replacing the resistor in the circuit with a variable resistor, plug in the phones, apply power and tune the current with the variable resistor so the current flow is 30mA. After that take out the variable resistor and measure the resistance/ohm across it. Find the fixed resistor with the nearest ohm reading to it and replace it to the circuit. Simple st Circuit Testing In Progress
More About: Simples , Intercom

Simple Cable Tester
2007-03-24 18:23:00
Simple DIY Cable Continuity Test er How to use This simple cable tester can be used to check 2 wire cable such as coax cable, telephone cable, audio cable and etc. Power the circuit using 9V battery. Plug in the cable and push "TEST" button. The dummy resistor is connected to the end of the cable which has 75ohm resistor inside. The tester will show only 3 conditions, "SHORT", "OPEN" and "GOOD". How it works The method is to check resistance of the dummy resistor at the "Terminator". The idea is simple. Imagine there is a short circuit cable under testing. The wire will act as nearly zero ohm resistor thus making the voltage divider near the dummy resistor to divide the 9V into 4.5V. Calculate it your self [ ( 1k / ( 1k + 1k ) ) * 9V = 4.5V ]. 4.5V is below than the lower "Comparator" limit (Vref 4.57V). It will trigger the lower "Comparator" and make "Short" LED to light up. Now for the open circuit cable. Assuming the open circuit cable has an infinite ohm. Voltage divider...
More About: Simple , Este

Biquad ant. for WLAN
2007-01-04 01:24:02
Biquad Antenna for 2.4 GHz - 802.11b/g - WiFi - WLAN After some research, I found out that the simplest type of homemade WLAN antenna is BiQuad antenna. Many sites provide good instruction on how to assemble it. (refer below) Biquad Antenna Construction Biquad Sector antenna for 2.4 GHz Building a biquad antenna for wireless 802.11b Trevor Marshall BiQuad 802.11b Antenna [My favorite] I'm not going to repeat it. My Antenna So I start by recycling some parts that I found in my workshop and construct it. I took about 10-20 min. for me to finished it. The critical process is to make the element. With proper method and dimension this thing will work. Good Luck!!!

Gates Oscillator
2006-12-18 13:11:01
Experiment With NAND Gate - CMOS 4011 (CMOS 4011 Layout) Circuit Try this super-simple experiment. The output frequency is about 1kHz (square wave).
More About: Gates

Touch Switch
2006-12-18 13:11:01
Experiment With NAND Gate - CMOS 4011 Output goes high when touch wires bridge by finger.
More About: Switch , Touch , Ouch , Witch

PC IrDA interface
2006-12-18 13:11:01
DIY IR interface This circuit is also from www.electronics-lab.com. Since it is very hard for me to get the infrared interface (TFDU4100), I start to look in the old/damage handphones. It looks something like this. Now, you need to remove it using the hot air blower perhaps. Connecting to motherboard Please refer to www.electronics-lab.com on how connect this irda module to your motherboard. My IrDA Infrared Transceiver Modules Here are the pin layout and picture of the device. Pin Description of TFDU4100 Pin Number Function Description I/O Active 1 IRED Anode IRED anode, should be externally connected to VCC2 through a current control resistor 2 IRED Cathode IRED cathode, internally connected to driver transistor 3 Txd Transmit Data Input 1 High 4 Rxd Received Data Output, open collecto...
More About: Inter , Face , Interface

S/PDIF - TOSLINK interface
2006-12-18 13:11:01
Circuit & Information on TOSLINK interface So you want to get a high quality audio for minidisc recording but when using red and white RCA, the quality drop drastically. Here a my cheap solution for you. Actually you can find a lot of references of this type of simple project in the internet. REF * S/PDIF = Sony/Philips Digital Inter face * TOSLINK = ( TOSLINK Interconnect History & Basics ) * Another web offering the same information * SPDIF at epanorama.net Meet my version of cheap, 2 components TOSLINK @ S/PDIF. Try to find a cable with connector from old PC casing for this. (HDD led,reset switch or power button connector) Assemble it using your own creativity. Use the pen tube for the light transmission. Connect it to the back of your CDROM drive. Since (D, the signal should go to anode and G should go to the ground/cathode) Test it out. you should see the light come out from the tip/tube. Connect to your MD or other device such as power amp t...
More About: Link , Face , Interface

ATX PSU Diagnose
2006-12-18 13:11:01
About ATX Power Supply ATX Power Supply converts the wall (AC) to the direct current (DC) needed by the PC. The power supply looks like a metal box with fan. Typical computer power supply generates the voltages needed by the computer motherboard accessories. [Read more...] Before Everything Disconnect all socket from your main board, HDD, CD/DVD drive, Floppy drive and etc so that we can isolate which part is not working. Step 1 - Check Wall AC power To check this, you may try to plug in any electrical appliances to the wall socket to verify that the 240V exist such as lamp, table fan or etc. If it is working, that mean the power from the wall socket is ok. You may also check the voltage with multimeter if you have one. Step 2 - Power Socket Fuse If you are using power socket with fuse, you may try to check this first. The method is to plug the other end to other appliances such as your printer (turn on to verify), monitor (turn on and look for LED indicator) or rice...
More About: Nose

Lab Power Supply
2006-12-18 13:11:01
Description and Circuit Make your own lab power supply complete with adjustable voltage and constant current source. Using single IC (LM324) Here are the circuit. Strip Board Layout. Part List 1 LM324 Opamp 1 Ammeter 100 µA 1k ohm 1 Voltmeter 6 IN4001 1 Zener Diode 9.1V 1 Full-Wave Bridge Rectifier 1 LED 2 NPN Transistor, 2N3055 1 NPN Transistor, BC109C 1 Transformer 2 E-Capacitor 2200µF 1 Potentiometer 5k ohm linear 1 Potentiometer 10k ohm linear 1 Resistor 500 ohm 2 Resistor 2.2k ohm 1 Resistor 560 ohm 1 Resistor 6.2k ohm 2 Resistor 68k ohm 1 Resistor 0.22 ohm 4 Resistor 4.7k ohm Component Image. LM324 2N3055 Some Pictures.
More About: Power

Telephone FM Transmitter
2006-12-18 13:11:01
Descrition & Circuit This project is taken from www.electronics-lab.com. With some modification, I create my own version of FM Tele phone bug complete with stripboard layout. Theortically, the frequency range is from 88MHz to 94MHz but you may experiment with the coil structure to tune it Circuit Strip Board Layout Parts List Diode IN4384 4 LED 1 Resistor 12k 1 1k 1 200R 1 Capacitor 470p 1 330p 1 25p 1 12p 1 Trans istor A933(PNP) 1 Coil *See note 1 *Coil note 7 or 8 turns of 22AWG(di...
More About: Phone , Telephone , Mitt