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  • John Bond followed nml235l5 months ago
      • Tractor-cardboarder
      • Paper Batman
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  • How to Use Photo Interrupters With Your ARDUINO

    Thanks for this clear and educational instructable.It's sad that a 555 has been suggested in the comments.1. Your project is MUCH more flexible. For example a second 555 (or a 556) is needed to drive a piezo.2. You are able get twice as many pulses than there are slots by reading the rising and the falling signal. By fitting a 2nd sensor on one of the available I/O and offset it by half the gap width, you can also read the direction of the movement. If you add more sensors and use a grey code strip/disk. You can get position. For example using 5 sensors, you could know the exact position to within 12°.3. If cost is a problem, use the Arduino compatable AtTiny85 with 4 or 6 I/O. This is 3 more I/O than the 555 and provides big additional benefits. You have timers, logic, state etc....

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    Thanks for this clear and educational instructable.It's sad that a 555 has been suggested in the comments.1. Your project is MUCH more flexible. For example a second 555 (or a 556) is needed to drive a piezo.2. You are able get twice as many pulses than there are slots by reading the rising and the falling signal. By fitting a 2nd sensor on one of the available I/O and offset it by half the gap width, you can also read the direction of the movement. If you add more sensors and use a grey code strip/disk. You can get position. For example using 5 sensors, you could know the exact position to within 12°.3. If cost is a problem, use the Arduino compatable AtTiny85 with 4 or 6 I/O. This is 3 more I/O than the 555 and provides big additional benefits. You have timers, logic, state etc. The AtTiny85 cost under US$2.00, hardly more than a handful of 555s (which the project will need) and a 3rd of the effort.Thanks again and well done

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  • John Bond commented on splats's instructable Laptop Battery Analyzer /Recycler3 years ago
    Laptop Battery Analyzer /Recycler

    This is an AMAZING device and can even be improved a little.I made a very similar device to test powerbanks at work about 18 months ago.A powerbank exploded in a user's pocket injuring him. We had relied on our supplier to test the devices. We set up a fairly rigorous testing regime. We tested not only our units but also the competitor's units and got to learn a huge amount about powerbanksWe eventually got hold of the exploding powerbank and found it was a fake copy of one of ours, very similar outside but without any protection circuit inside.Some notes:- * Our Chinese powerbanks seldom fail and when they do, they fail safe * They usually have an efficiency in excess of 83% * The power delivered is very smooth. Less than 10mV spikes. 0.4V to 0.7V total voltage variation throu...

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    This is an AMAZING device and can even be improved a little.I made a very similar device to test powerbanks at work about 18 months ago.A powerbank exploded in a user's pocket injuring him. We had relied on our supplier to test the devices. We set up a fairly rigorous testing regime. We tested not only our units but also the competitor's units and got to learn a huge amount about powerbanksWe eventually got hold of the exploding powerbank and found it was a fake copy of one of ours, very similar outside but without any protection circuit inside.Some notes:- * Our Chinese powerbanks seldom fail and when they do, they fail safe * They usually have an efficiency in excess of 83% * The power delivered is very smooth. Less than 10mV spikes. 0.4V to 0.7V total voltage variation throughout the cycle * Some of the competitor's powerbanks are not very good (read "dangerous!")Features I incorporated that may enhance any power measurement device:- * We rapidly sample 1000 times (to increase accuracy) and record the average, the max and the min in a spread sheet * This is repeated 40 times a second until the unit is discharged * We use a variable load (mosfets and some opamps) but have found that we always run it at 1 Amp. The technicians can then compare different powerbank models against each other. * Our customers sometimes ask us to test units that have been returned to them and the units generally (almost always) pass. The weak link in powerbanks is the power cable.A word of caution - Our company has come to rely on this simple device more than the sophisticated equipment used by our suppliers (not a good idea). We have challenged new suppliers on the results. The suppliers tend to get very annoyed when they discover out test equipment is an Arduino and some opamps, lying loose on a workbench...

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