switches Raspberry Pi GPIO


Posted on Feb 7, 2014

Experiments with couple of floppy drives I have and it appears that on the step pin, current is limited to around 5 mA. This means that we can indeed omit the collector resistor in this case. For base, I`d recommend a 1 kiloohm resistor. This will give us 3. 3 mA coming into the base of the transistor, which should be more than enough to saturate usual small signal transistors. Another point worth


switches Raspberry Pi GPIO
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mentioning here is that same setup will most likely be needed for the direction pin as well, in order to prevent read heads from colliding with end-stops. Some floppy drives have security mechanisms which will prevent the stepper motor from forcing the head when the disk is inserted. I was about to make a really long comment, but then decided that it`s better to turn it into an answer in hope that you`ll be able to better understand our standpoint. First, you`re being difficult to work with! That may not be obvious to you, so I`ll try to explain: You came to us with a question that looks basic and emits air of someone who isn`t very experienced with electronics. In your question, you already have some idea for a solution to your problem (which is good, since in general we like it when people post questions they thought about) and then you exclusively ask for help related to implementation of your solution and are avoiding any information that could lead us to provide any other way to accomplish your real objective (which is bad). The problem is that your solution (as you posted it) is in direct conflict with what we got as a part of basic electronics training! This is NOT a minor thing. I`ll provide an analogy which will hopefully make this a bit easier to understand. Imagine this scenario: You just spend a whole evening drinking alcoholic beverages with your friends and can barely walk in a straight line. Now you`re...




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