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Posts with «magnets» label
A first-time visitor to any bio or chem lab will have many wonders to behold, but few as captivating as the magnetic stirrer. A motor turns a magnet which in turn spins a Teflon-coated stir bar inside the beaker that sits on top. It’s brilliantly simple and so incredibly useful that it leaves one wondering why they’re not included as standard equipment in every kitchen range.
But as ubiquitous as magnetic stirrers are in the lab, they generally come in largish packages. [BantamBasher135] needed a much smaller stir plate to fit inside a spectrophotometer. With zero budget, he retrofitted the instrument with an e-waste, Arduino-controlled magnetic stirrer.
The footprint available for the modification was exceedingly small — a 1 cm square cuvette with a flea-sized micro stir bar. His first stab at the micro-stirrer used a tiny 5-volt laptop fan with the blades cut off and a magnet glued to the hub, but that proved problematic. Later improvements included beefing up the voltage feeding the fan and coming up with a non-standard PWM scheme to turn the motor slow enough to prevent decoupling the stir bar from the magnets.
[BantamBasher135] admits that it’s an ugly solution, but one does what one can to get the science done. While this is a bit specialized, we’ve featured plenty of DIY lab instruments here before. You can make your own peristaltic pump or even a spectrophotometer — with or without the stirrer.
Filed under: chemistry hacks, tool hacks
[Daniel Perdomo] and two of his friends have been working on a mechanical version of Pong for the past two years. We can safely say that the final result is beautiful. It’s quite ethereal to watch the pixe–cube move back and forth on the surface.
[Daniel] has worked in computer graphics for advertising for more than 20 years. However, he notes that neither he nor his friends had any experience in mechanics or electronics when they began. Thankfully, the internet (and, presumably, sites like Hackaday) provided them with the information needed.
The pong paddles and and pixel (ball?) sit onto of a glass surface. The moving parts are constrained to the mechanics with magnets. Underneath is a construction not unlike an Etch A Sketch for moving the ball while the paddles are just on a rail with a belt. The whole assembly is made from V-groove extrusion.
Our favorite part of the build is the scroll wheel for moving the paddle back and forth. For a nice smooth movement with some mass behind it, what’s better than a hard-drive platter? They printed out an encoder wheel pattern and glued it to the surface. The electronics are all hand-made. The brains appear to be some of the larger Arduinos. The 8-bit segments, rainbow LEDs, etc were build using strips glued in place with what looks like copper foil tape connecting buses. This is definitely a labor of love.
It really must be seen to be understood. The movement is smooth, and our brains almost want to remove a dimension when watching it. As for the next steps? They are hoping to spin it up into an arcade machine business, and are looking for people with money and experience to help them take it from a one-off prototype to a product. Video after the break.
Filed under: classic hacks, Virtual Reality