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  1. chopnhack

    Smartphone spectrometer

    Well, maybe not yet, but with quantum dots it maybe sooner than you think! http://www.zmescience.com/research/technology/spectrometer-small-smartphone-053434/
  2. chopnhack

    Happy Fathers Day!

    To all who celebrate! I received the traditional tie - well needed. I got dad a cordless tool set, his old one is from the stone age, very heavy and still had nicad batteries! How about you?
  3. chopnhack

    Differences between LTSpice and Real circuit and why?

    Maybe someone can attempt to help on this question. As you can see below in the waveform, the circuit works as expected. I added C3 to smooth out the transitions between the oscillations. The value was derived by watching the output until it was clean. D3 is an LED that in real life shows only...
  4. chopnhack

    More efficient LDR "dark" switch?

    Can anyone assist me with making a LDR switch? I specifically need a high efficiency and inexpensive setup since the intended circuit will run off of one 2032 battery. The switched circuit will consist of two small led's and a very low draw IC. The switch as pictured below gets switched on when...
  5. chopnhack

    Decoupling a cmos based 555?

    Do you think that a 7555 requires decoupling the input voltage if it is battery fed? Please leave your reasoning in the reply, thanks!
  6. chopnhack

    CircuitStudio by Altium

    I got an email from Element14 giving a free 30 day trial of CircuitStudio. Thought it was cool and wanted to share. Be warned though, the program is big bucks!! Eagle may have a steep learning curve as CircuitStudio literature points out, but the price is right :-)...
  7. chopnhack

    8-Pin Development Board

    I just completed a schematic for a 8 pin PIC dev. board to get some hands on experience with a simple mcu. Six I/O pins shouldn't get me into much trouble, I hope! Can anyone review this? I am looking for errors as well as suggestions. I think that what I have shown will allow some simple...
  8. chopnhack

    What is the diode going to?

    Does anyone know what the diode is connected to at the top left hand corner?? The datasheet recommends this method of connection to protect the μcu, which makes sense with high voltage programming potentially damaging the chip. I'm just a little confused as to why its not labelled and what is it...
  9. chopnhack

    16 bit 2-1 mux assistance

    I am trying to finish a lab for an online course - no credit, just for knowledge and I am not sure if I didn't understand the principal correctly or if the online grader is not getting what I am putting down. The first picture is the "innards" of the the 2-1 mux that is then replicated with a...
  10. chopnhack

    EP Newsletter

    Did anyone else receive the newsletter? I think its a great idea, especially for folks that don't frequent the site that often. A nice aggregation of posts. Of course, I am biased as I was top billed :oops: . Hey, even a broken clock is right twice a day :D
  11. chopnhack

    Incrementing Slice in Python?

    Hello again, I need assistance on a question - no spoilers, just a direction if you will: I thought I could increment a slice function --> s1[i+1] but Python doesn't allow that operation. def laceStrings(s1, s2): """ s1 and s2 are strings. Returns a new str with elements of s1 and s2...
  12. chopnhack

    Tips for learning recursion?

    The course is moving right along and makes me wish I had more time to keep up with it!! Currently I am having difficulty following recrusions. The idea sounds wonderful, just like when you took an interating loop and bundled it up into a function. In practice, it almost looks like a self calling...
  13. chopnhack

    Can you use serial communications on ethernet?

    Today's question comes from seeing this: http://www.instructables.com/id/How-to-Make-a-9-Pin-Serial-to-Ethernet-Cable/?ALLSTEPS I may have need of converting serial to ethernet, old legacy equipment that still works well, but is technologically outdated unless I can put it on the network. This...
  14. chopnhack

    Python programming course help

    Problem 3: Alphabetical Substrings Assume s is a string of lower case characters. Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, if s = 'azcbobobegghakl', then your program should print Longest substring in alphabetical...
  15. chopnhack

    Define a Function - brutishly

    LOL - My homework was completed, however, I think it was by force rather than skill: L4 Problem 10 (5/5 points) Define a function isVowel(char) that returns True if char is a vowel ('a', 'e', 'i', 'o', or 'u'), and False otherwise. You can assume that char is a single letter of any case (ie...
  16. chopnhack

    Exchanging data variables?

    This is homework so no spoilers please! The goal of the assignment is to create a program to guess your secret number from 0(inclusive)-100(not inclusive). I have made some headway, but I am having trouble creating a proper iteration that will collect the response and then based on the three...
  17. chopnhack

    Question on use of Python language

    I enrolled in MIT's Intro to CS and Python Programming to help me better understand general computational thinking. I was 1/2 way through week 2 until I hit a snag that I haven't been able to pick apart. The for <> in <> loop has got me confused. Here is a sample: iteration = 0 count = 0 while...
  18. chopnhack

    Single Transistor Circuit Current Question

    Self assigned work, not homework, but seemed more appropriate to post here. I built a small circuit from a video course I have been watching. The assignment is below, but I modified it to work with parts I had on hand: Namely, I didn't have an LDR nor a small incandescent bulb, so I just...
  19. chopnhack

    Suggestions for building a PIC dev. board?

    I am interested in building a development board for PIC μcu's. I know that this is a broad area since it depends greatly on what PIC you are using and what i/o you want to use/have read in etc. This is where I am having the difficulty. I don't know what I don't know! What should I as a novice...
  20. chopnhack

    Cool circuit plotter with conductive ink

    Kudos to the students!
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