Tag Archives: electronics
RAMPS 3D Printer Electronics Enclosure

imageWhen you build your own 3D printer you can put the electronics just about anywhere.  I chose a RAMPS 1.4 enclosure off of Thingiverse and then modified the sides to my liking.

Read More…

Educational Circuit Box DIY

imageHere is a fun project you can do with your kids. It’s a project box with battery, switches, LEDs, vibrating motor, and whatever else you can come up with. it uses header pins and jumper wires to enable the user to connect circuits. Read More…

DIY The Most Useless Machine

The useless machine is a simple box with a switch and motor, when you turn on the switch the lid opens and the arm swings out and turns off the machine and then retracts. It is so simple but brings a smile to the face of everyone that tries! The Useless Machine was not created by me, it can be found in Make Magazine and in numerous Instructables and DIY articles online. Read More…

What is a potentiometer?

A potentiometer is a variable resistor used to resist electrical current.

image Read More…

What is a diode?

A diode is a semiconductor that only allows current to flow in one direction, it is a one way valve for electricity.

Diodes come in all shapes and sizes, the most important difference in them is the current rating, i.e. how much you can push through without overheating and burning the diode up. Here I demonstrate different diodes.

Here I show how to test a diode. Testing is done with a multimeter, an analog multimeter is preffered.

Here is some information on the numbers you may find on a diode.

First Letter

Specifies semiconductor material

Second Letter

Specifies type of device

Subsequent Characters






Gallium Arsenide


Compound materials


Diode – low power or signal


Diode – variable capacitance


Transistor – audio frequency, low power


Transistor – audio frequency, power


Tunnel diode


Transistor – high frequency, low power


Miscellaneous devices


Diode – sensitive to magnetism


Transistor – high frequency, power




Light detector


Light emitter


Switching device, low power, e.g. thyristor, diac, unijunction


Transistor – switching low power


Switching device, low power, e.g. thyristor, triac


Transistor – switching, power


Surface acoustic wave device


Diode multiplier


Diode rectifying


Diode – voltage reference

The characters following the first two letters form the serial number of the device. Those intended for domestic use have three numbers, but those intended for commercial or industrial use have letter followed by two numbers, i.e. A10 – Z99.

DIY Sound Localization Sensor

I searched for days trying to find a commercial sound localization sensor or info on how to build one. Sound localization is what the human ear does when it determines that a sound is coming from the left or right. After talking to some gentlemen over at the Arduino forums I realized that it wasn’t going to be as simple as I thought.

I finally hacked together something that works great for my first try, there is a lot of work to be done though. The sensor works fairly well from a foot or so away, after that you really feel the limitations of my circuit and only doing a volume comparison from the microphones.


Here are the related project files. Sketch Audio_Localization  and schematic SoundLocalization


DIY Sound Localization Sensor

I am aware that the LM324N is not specifically a comparator but can work as one, it seems to do the job.

If you are interested there are some videos on YouTube regarding sound localization but they only demonstrate the sensors and give no helpful information on building one yourself.

I may in the future try to use an ARM Cortex M3 proto board I purchased from Texas Instruments (EKK-LM3S811 Evaluation Kit) to do phase shift comparison calculations for sound localization, the Arduino is nowhere near fast enough to do this. After reading some information I believe you need to be able to sample and do a calculation in 10-50 micro seconds in order to get usable data.