Interesting to the extreme, you have never seen any display - a large ferromagnetic fluid display from 0 to 1 DIY based on Arduino + PWM modulation technology

This is a student project at the University of Oslo, designed and manufactured large ferromagnetic fluid displays with 252 electromagnetic "pixels". The display has a resolution of 12x21 (we are closest to the acceptable 16: 9 resolution display) and is currently in the final test phase. The matrix housing will control ferromagnetic fluids and act as a simple display frame, so it has some limitations. The most obvious disadvantage is that the mechanical time delay caused by the slowly caused by the ferromagnetic fluid itself. It can only be moved very slow because it has a transformer gravity - which means that it is impossible to miracle to display a pixel or even super fast movement to a place for the display. This means that we are unable to get any help from visual persistence as normal screens. In addition, gravity ensures that if the adjacent magnet is powered, more ferromagnetic fluid will accumulate on the lower pixel, and the upper pixel is emptied. Therefore, our system requirements basically explain: 1. Each pixel must be powered separately. 2. The system must implement ways to apply different retention for each pixel. Now, for the second point, an obvious solution is that the PWM is modulated to supply the power supply per magnet (as described in Point 1). However, we don't know how 252 PWM pins microcontrollers. Therefore, first we have to find a way to extend the number of pins required to any quantity. The solution we use is serial -> Parallel shift registers. This solves the first point, but let us get from the single PWM function, the method of solving this problem is to implement PWM in the software. This is not the best choice because it makes our PWM frequency depend on the execution time of the primary loop. However, through some recent upgrades, we seem to have some room for us to give us a lot of frequent jitter. Prototype (based on Arduino Mega) We are not sure how to choose the hardware device of the project at the beginning, so the only logical thing is to start with 252 pixels "monsters" than our plan. Therefore, we construct a smaller 6x6 prototype and connect it to a single drive PCB (up to 28 magnets, so we only connect 6x5) to test all working principles. As a result, we are very good, so we continue to work on the design you can use in the final show. When we have completed the full size display, we may re-open a relatively small version, and do a separate project on this basis, because for other ferromagnetic fluid enthusiasts, it needs to be more cheap and easy to copy . Be Be Article Source HackADAY

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