Fresh hacks every day
[Arao] wanted to measure the RPM of a spinning wheel using parts that he could scavenge from his junk box. A bit of thought led him to build a reflective sensor which can measure the spinning of a wheel (translated). He got his hands on an infrared phototransistor which had been used as part of the remote control for some consumer electronics. Snooping around with his multimeter helped him … [Read more...]
Sound localization is very popular in law enforcement circles due to its accuracy and ability to quickly separate gunshots from other similar noises. These systems don’t come cheap, and after trying to build one himself, [Fileark] knows why. He thought it would be neat to build a sound localization sensor based on how the human ear determines a sound’s source. Once he got started however, he … [Read more...]
[nickinoki] Made a light show using some amplifiers and an arduino. First he created a microphone circuit based around a LM386 Audio Amplifier. After amplifying the output of the microphone a second time, he uses three bandpass filters to block all but a few desired frequencies from reaching the arduino. By only letting a few frequencies through the arduino is able to determine if the song is … [Read more...]
The Segfault is a balancing transport similar to a Segway, but it uses analog comparators instead of digital circuitry. On board you'll find no less than twelve LMC6484 op amps. They take signals from the gyroscope and the accelerometer, balance and filter them, then drive the motor h-bridges accordingly. [Charles], the guy behind the Segfault, is also the one responsible for DeathBlades. As … [Read more...]
[Manekinen] built a very responsive spectrum analyzer. The components at the party are what you'd expect, an ATmega8 does the hard work interpreting data from the LM324 op-amp. This build stands out because it is fast and configurable. In fact, the explanation of the calibration process is where this project shines. Instead of using water, an HD44780 module displays the spectrum data. The … [Read more...]
Although we've covered DIY ECGs before, [Scott Harden] sent in his version that gives an in-depth explanation of what to do with the collected data. He built a basic battery-powered op-amp-based ECG for under $1. The circuit just amplifies the signal from the chest leads and feeds it into a computer via the microphone port. He then used GoldWave to record, filter, and save the signal. From there, … [Read more...]
[Marcus] sent in his work on making ECGs. His first one was inspired by [Jason]'s. Believe it or not, you can build this thing for under $5. After getting it semi-functional, he decided to pick up a cheap one and mod it for PC input via the sound card. (There are plenty of sound card oscilloscope projects that will work for this.) Remember kids, don't go sticking electrodes on anyone unless you … [Read more...]
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