Fresh hacks every day
This pulse oximeter is so simple and cheap to build it’s almost criminal. The most obvious way to monitor the output of the sensor is to use an oscilloscope. The poor-man’s stand-in for that is a sound card, which is what [Scott Harden] demonstrates in his write-up.
It uses a concept we’ve seen a few times before. The light … Read the rest
[Tim] wanted to help out a ECE student struggling with some Op-Amp problems. He put together a video which does a good job of explaining what an Op-Amp does, then tackles each of the questions one at a time.
His analogy is illustrated in this image. There’s an operator using a crane to lift a crate. He is watching … Read the rest
The lion’s share of soil moisture monitors we see are meant as add-ons for a microcontroller. So we’re glad that [Miceuz] tipped us off about this soil moisture alarm he built with analog parts. It’s really not hard to take the concept and build it in the analog world. That’s because you’re just measuring a resistance value. But for … Read the rest
[Michael Chen] felt the sound his PSP was putting out needed more dimension. Some would have grabbed themselves a nice set of headphones, but he grabbed his soldering iron instead and found some space where he could add a bigger speaker.
Mobile devices tend to cram as much into the small form factor as possible so we’re surprised he … Read the rest
This is a Digital Salinometer which [Daniel Kramnik] built as a Science Olympiad entry. He’s a Junior in High School and when looking for a project to enter into the Water Quality event he was interested in achieving greater accuracy than a mechanical hydrometer provides.
We think the circuit design is very impressive for anyone who hasn’t complete formal training … Read the rest
[Minisystem] has a thing for dynamo powered bike lights. He wanted to measure how well his latest is working, but just logging the current flow through the LEDs wasn’t enough for him. He picked up a cheap Lux meter and hacked into the circuit to log measurements while he rides.
He started by cracking open the case to see what … Read the rest
[Phil] picked up an HD radio receiver when Radio Shack was clearing them out at a 60% discount. But to his disappointment, when he hooked it up the sound left a lot to be desired with limited mid-range and flat bass. After some forum mining he discovered that the optical output didn’t have this problem, and came to the conclusion … Read the rest
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