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    Programmable Dot Matrix Display System

    There are some legacy character generator chips out there, I saw a spec sheet for one a few years ago. You're going to have an easier time programming your own set on an EPROM of some sort. You're going to have to come up with some addressing hardware though. I am curious. What issues forbid...
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    UPS Question..

    Let me add to that. 4. Automotive batteries do not take well to being fully discharged. Ideally you should use a "deep cycle" battery. The internal construction is slightly different. If you never use it longer than necessary to save your work and shut down, then this won't be a problem.
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    NICAD Battery charger/reconditioner HELP

    Moltra, I'm going to have to rain on your parade. Reconditioning NiCads is temporary, and some say of debatable value. Two failure methods come to mind (I'm no expert)- 1: the electrolyte was cooked dry, 2: the electrodes grew dendrites. The second one can be fixed, but it won't last. The...
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    detector prototype

    A detector will tell you how noisy an appliance is, but will not let you measure the power being consumed. You may be better off trying to find a non-invasive way of sensing the current through the power cord, though I suspect that will be difficult and you will have an easier time plugging the...
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    touch switch

    I'm sorry 12412, I don't particularly care for it. It makes me directly part of the circuit. I was hoping for (have seen once, and hope to find again) one that uses capacitive coupling.
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    Transformerless power supply

    There is a safe way- in a grounded steel box that also contains the device being powered with no wires leaving without being isolated. If there is no denying that you need a small, light power supply for more than 30V and less than 30mA then build one. If you do then be sure that you use...
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    Transformerless power supply

    Be aware that connecting neutral to earth at the device, as advised in Microchip's appnote, is likely to cause a GFCI breaker to trip.
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    Transformerless power supply

    MP, I reccommend both wires regardless of the configuration (hot-neutral-ground or hot-neutral/ground-hot) because this is for a single phase bridge rectifier. This means that on the negative half cycle the "hot" input will be clamped to ground while it pushes the "neutral" positive. This...
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    Night rider scanner

    Have you considered using a microcontroller for this?
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    Transformerless power supply

    If you can manage it, you should consider putting a capacitor and a fuse inline with both mains leads between the cord and the rectifier. This will offer some safety margin (not enough to bet your life on) and allow one end of the output to be tied to ground.
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    What is a reasonable frequency?

    It depends on what you're using it for. If it's for PWM control of a motor, then 1kHz may serve you. It can be divided from most oscillator crystals that are likely to be used with uCs (sorry, lazy- didn't look for the code for 'mu').
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    pseudorandom sequence decoding

    Wow, what a mouthful! But seriously, I've looked for articles on this by the name above and by binary chain decoding. I haven't found anything written for my level (lower than it may seem). What drives me is that an encoder wheel of 2^n bits could be fashioned such that reading n bits would...
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    motor controller protocols

    Good morning MP, and thanks for showing interest in my (possible) future project. I guess I'm having trouble communicating clearly, and made the classical (arrogant) mistake of trying to meter the information to narrow the response. Last question first. I'll be using a 16c73a. I obtained...
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    motor controller protocols

    By protocol I mean that I'd like to know how the request/command is structured for a serial bus, and what all information it includes. For servos I found a three byte protocol, the first of which only synchronizes the bus. I'd like to see more. For steppers I hope to find one or more...
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    motor controller protocols

    Hey folks! I'm thinking about making a dedicated controller for steppers and another for servos. I'm having trouble wading through the articles and advertisements to find the protocols being used. I did see one on servos though. Links are best, thanks.
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    5 volt regulated power supply HELP!!!!

    You might look into using an smps. Check out the "black regulator" at http://www.romanblack.com/
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    led driver

    Second question: Yes. First question: Three external components help with the task of step-up voltage conversion. One inductor, one capacitor, and one schottky diode.
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    simple PWM

    It doesn't get much simpler. The chip can be a 40106 with minor changes. There is something that uses all discretes at http://www.romanblack.com/ One downside to these designs is that the frequency is not controlled, and as such may have some annoying side effects. For a motor control this...
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    led driver

    Microchip and Maxim give away free samples. Just answer their questionnaires honestly. Unfortunately the packages are all SMT. As for the discretes, if you can get some used disposable cameras with flash units (some places will give them away since they're garbage) the charging transistor is...
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    led driver

    For driving white LEDs from a lower voltage than Vf there are chips from Maxim, Microchip, and (probably) National. You'll have to do a parametric search for them. http://www.maxim-ic.com/index.cfm http://www.microchip.com/1010/index.htm http://www.national.com/ There are also discrete...
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