NUTS AND VOLTS

Posted in: Nuts and Volts

The Counting Box

The initial concept was simple: a seven segment LED display so it could be read in the dark,  a rotary switch in the middle to choose the value to operate with, and big buttons for adding and subtracting.  Green makes the number get larger and red makes the number get smaller.

The electronics were first, since the size of the case would depend on the size of the finished electronics. I ordered these 4-digit seven-segment displays and this 10-position rotary switch from Mouser, and these video game buttons from Sparkfun. It would all be driven by a standalone ATMega 328 on a perfboard. The picture below shows the finished circuit right before I mounted it into the box.



The display is driven by a MAX7219 chip, which can drive 64 LEDs or 8 seven-segment digits with only 3 output pins on the ATMega. Interfacing with this was easy, with the only difficulty coming from keeping track of which wire was which when linking to the LEDs. Counting up to 99,999,999 might take a while, but it’s good to have goals, right?





[Source] HahaBird- The Counting Box


Comments

  • submit question
  • reader feedback
  • submit ideas

Projects:

  • USB, LEDs, and Some Sensors

    Turning LEDs on and off is fun and all, but why not add a sensor or two that would be useful for something other than the usual light show? Read More...

  • The Versatile Wireless Doorbell

    Advances in technology often decrease price points, but not usefulness. See how to turn one circuit into several devices that most homeowners would find invaluable. Read More...

  • Frequency Counters and Retrofitting

    Even the lowest grade frequency counters are often the most accurate instruments on the test bench. This article will describe their general principle operation, but more specifically on the construction and retrofitting into existing equipment such as the sweep generator and RF signal generator covered in recent issues. Plus, we'll take a look at expanding added features, all the way to a full blown universal counter. Read More...