Boilersrock

One thing I had to add was a power-up RESET circuit, which is just a 10uF cap and 1K resistor in series across the 5v supply. The RESET pin on the counters are connected to where the resistor and cap meet so that at power up, the cap is effectively a short to 5+. This causes a logic HI on the RESET lines to set the counters to zero. After the capacitor has charged up, it no longer looks like a short to 5+, so the only path left is through the resistor back to ground. That presents a logic LOW on the RESET pin, which allows the counter to count up or down.

My second order arrived with more wired, LEDS, decoders and stuff earlier today. So I spent this evening hooking everything up pretty much as my original schematics indicated. I had to add a few bypass caps on the breadboard to keep stray voltages from disrupting everything. Attached is a video of the counter counting DOWN, with the clock signals coming from the 555 circuit. I have a switch on the main bread board switch between counting UP or DOWN right now. Exciting, yes? I think so.

I am a bit worried though because the box showed some obvious damage. I took some pictures before opening it just to be safe. Afterwards, I looked at the LEDs closely, and there doesn't seem to be any cracks or visible damage. I won't be 100% sure until I get home and run some voltage through them later tonight (to be continued)... Well, so far so good for the first LED. I soldered up a bunch of leads to the first board connected them to the breadboard. I've got all 7 segments lit up going through 3 22 ohm resistors wired in parallel off of a 12.4 supply.

Here is my initial design and draft of the circuit used to control the Digital Counter. The counter will have a One's and Ten's digit which allows it to go from "00" to "99". There will be three buttons: Reset, Up and Down I've decided to start with a pair 74LS192 chips to which are Decade counters (count from 0 to 9). Upon reaching a value of "9", the counter jumps back to Zero and outputs a Carry signal. That Carry signal is used as the clock signal for the Decade counter that handles the Ten's digit. Each 74LS192 is connected to it's on C4511 BCD-to-7 segment display decoder. As the name suggests, the 4511 converts the Binary number coming from the 74LS192 to signals that can drive a 7 segment display. There are blanking and lamp test inputs available, but I've no plans to use them for now. The display LED's I plan to use are found here ( www.sparkfun.com ). The current draw of each LED segment is 20ma, a bit much for t

I've decided to work on a new electronics project. My original degree is in Electrical Engineering Technology and it's been a long time since I had a chance to piece together IC's (integrated circuits), printed circuit boards, buttons and displays. The reason for this project is two-fold: First, I want to show my kids some interesting electronics stuff that they can work on. I bought them a simple snap-together electronics kit a few years ago, which they enjoyed playing with. However, after putting together every project listed in the guide, they grew bored with it. Now that they're a little older, they can take on more challenging projects. Second, I like to play pickup basketball. One issue that comes up is scoring, so I figure that I can build a pair of these displays and then bring them to wherever I play ball. We always have people waiting on the sideline to play; someone would likely be interested in running the scoreboard. Ultimately, I plan to use this pa