Love Inspires CD Player Hack

The heart is an impressive piece of hardware. It’s a rare pump that runs continuously for over 80 years in some cases. It’s also, for some reason or other, become a common human symbol of love and affection. In this vein, [Deepak Khatri] has built a beating electronic heart out of basic, readily available components.

The heart of the build (pun intended) is a lens assembly salvaged from a CD player, which uses a coil and permanent magnet to move the lens in order to read across a disc. In this case, the coil is instead fed pulses from an astable multivibrator circuit built with a hacker favourite, the 555 timer IC. It’s all assembled on a breadboard, which is a great way to build such projects that rely on experimentation through the swapping of component values.

The end result is rather satisfying. [Deepak] has also experimented with an Arduino driven version with a slightly different rhythm.

We haven’t seen too many projects using optical drive lens assemblies, but we’re sure there must be other applications. If you end up using one to agitate biological samples or build an awesome laser projector, be sure to hit up the tips line. Video after the break.

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Beating Life-Force Amulet

It’s one thing to see science-fiction slowly become reality, but quite another to take that process into your own hands. Inspired by a movie prop, [Eric Strebel] decided to build himself a 21st science-fiction artifact: a pulsing, life-force amulet.

At the — aheam — heart of this amulet is a blinking LED circuit which [Strebel] modified into a slow pulse with the help of his friends. To add to the surreal quality of the amulet, he sourced a stone from a local gem show, bringing his circuit along to get an idea of what the final product would look like. Once [Strebel] had shaped the stone to a more manageable size, he took a polyester filler mold of its rear face to use as a base from which to cast a durable resin housing for the circuit.

[Strebel] is using a pair of coin cell batteries which fit snugly behind the glowing LED, and in case he ever needs to get inside the amulet, he’s attached the stone to the rear with sew-on straps — super-gluing them to each piece. He went for a bit of an industrial look for the necklace — a braided oil line with a modified quick-release clasp that works like a charm.

How does this amulet stack up to one from the 23rd century? You be the judge!

Hackaday Prize Entry: Thingspeak IoT Heart Rate Monitor

[Naman Chauhan]’s 2017 Hackaday Prize entry consists of a heartbeat detection and monitoring system that centers around everyone’s favorite WiFi board, the ESP8266. The monitor is hooked up to the patient’s finger, keeping track of his or her vitals and publishing the data on the cloud.

By using Thingspeak to manage the data, [Naman] leverages the platform’s data visualization and analytical features. Also, by making the data accessible on the cloud, he offers an intriguing opportunity to help friends and relatives to monitor the data. If you think about it, if you had a loved one in the hospital, wouldn’t having all of his or her chart available on your phone be great?

Simple And Inexpensive Heartbeat Detector

There are many ways to detect a heartbeat electronically. One of the simpler ways is to take [Orlando’s] approach. He’s built a finger-mounted pulse detector using a few simple components and an Arduino.

This circuit uses a method known as photoplethysmography. As blood is pumped through your body, the volume of blood in your extremities increases and decreases with each heartbeat. This method uses a light source and a detector to determine changes in the amount of blood in your extremities. In this case, [Orlando] is using the finger.

[Orlando] built a finger cuff containing an infrared LED and a photodiode. These components reside on opposite sides of the finger. The IR LED shines light through the finger while the photodiode detects it on the other side. The photodiode detects changes in the amount of light as blood pumps in and out of the finger.

The sensor is hooked up to an op amp circuit in order to convert the varying current into a varying voltage. The signal is then filtered and amplified. An Arduino detects the voltage changes and transmits the information to a computer via serial. [Orlando] has written both a LabVIEW program as well as a Processing program to plot the data as a waveform. If you’d rather ditch the PC altogether, you might want to check out this standalone heartbeat sensor instead.