Cell Phone Jammer for Your Conference Room or Office Meeting Place

It’s really annoying at times when you’re in the middle of a business meeting then suddenly your cell phone rang at full volume because you forgot to put it on a silence mode. It’s really an awkward moment when someone is in the middle of giving a report and the phone rang and stopped the speaker from talking.

So I found this easy DYI cell phone jammer that we can put in the conference room or meeting place. It uses the 555 timer [8 pin] IC coupled via C4 [electrolytic] to modulate the MRF transistor oscillator.

Alternatively, we can replace the 555 chip with an electrets microphone. It will also be good to build the unit into a metal box, add an on/off switch (useful when the conference room is not in use for meetings but on other purpose) in the batteries + line, and also put a LED in there. Then connect an old 800 MHz cell phone antenna to C5.

This device’s “Cell Kill Distance” is around 10 – 15 feet, ample for most purposes, so it’s really a good room type cell phone jammer.

Let’s Build a Simple JDM programmer

So my latest project involves the use of PIC12, PIC16 and PIC18 family microcontrollers, but was not really sure how to use them without a new MCU. So I was looking for solutions on the internet on how to do that and found this tutorial of DIY JDM Programmer.

I also found this PIC and EEPROM Programmer that will let us burn the program into the microcontroller chip through small software known as winpic800.

The first DIY JDM programmer tutorial uses a RS232 DB9 port to program the code into the microcontroller. I will be a bad idea to use a laptop if you’re using a DB9 port since most laptop nowadays don’t have the port, instead the tutorial recommends to use a desktop computer which comes with an inbuilt DB9 serial port.

Pulse Width Modulation DC Motor Controller, How to Control It?

I was planning to create a PWD DC motor control using a variable resistor or variable resistor connected to a transistor. The problem with this setup is that it generates heat and hence wastes power.  So I research for some good PWD modulation DC motor control to eliminate these problems. The PWM controls the motor speed by driving the motor with short pulses. The pulses created vary in duration to change the speed of the motor. The longer the pulses, the faster the motor turns, and vice versa.

I also found this PWM DC Motor Controller the uses MOSFETs, also if uses an IR2110 H-Bridge Driver. The H Bridge configuration is commonly used in electrical applications where the load needs to be driven in either direction.

I will try to find if this two projects can be customize or the specifications can be joined together to create a better PWM DC Motor Controller. I will post updates about my progress here.

So I was Going Build This Awesome Audio Amplifier

For the longest time, I’ve been planning to build an Audio Amplifier for my room. I love listening to music, everybody does right? So I’ve done some research on what’s the best amplifier for my room. Then I found this high power audio amplifier that gives a 300 watts output. But man, this kind of output is huge so instead of using this for my room, I’ve decided to use it the whole house audio system. My family loves karaoke and loves to watch movie together, so this is perfect for that.

This 300 watts audio amplifier has a good circuit design in my opinion. According to the tutorial, the circuit has been designed to produce an audio amplifier that can be used for low efficiency speakers or outdoor sound systems since it can deliver 300W of power, so you can use cheap speakers and still create some good quality sounds.

We’ve seen this 300 W power amplifiers and are widely used in commercial installations, video conferences systems, houses of worship (so we can frequently see one of these on churches), hotels or motels, for driving small & medium-sized live PA systems, for bars, clubs, & restaurants, for live sound venues, and for industrial & retail stores. They are mostly preferred since they deliver reliable power, low distortion, and clean output in any occasion and in any time of events.

How to look for your misplaced Cell Phone

Misplacing your cell phone can sometimes be annoying. This is a common problem among people who are busy and people who suffers short term memory loss.

I’m a quite a busy person and sometimes forget where I have place my cell phone whether at the house or at the office. So I look for solutions to the problem. The solution, a cell phone detector! How cool is that!

I found out this interesting cell phone detector project here. What’s cool about the project is that a circuit was design to detect signals being used in the GMS.

First was to create the PCB found on the pdf provided. The detector uses LM358 that amplifies the received signal from the cell phone.  It contains two separate op-amps that are supplied by a common power source. R3 and R7 resistors determine the gain of the amplifiers. When the resistor values are greater than 10M then the noise level increases. If they are small like about 100k, this time it becomes harder to hear the signal.

So there you go, a nice cell phone detector if your too annoyed looking for your misplaced cell phone.