Thursday, June 19, 2014

Digital Circuits - PDF Circuits - delabs

These circuits are based on CD40xx Chips and other. You can use 74HCT or any other series that is available. use one family for a particular project. These were used nearly two decades ago. Use it for learning, glue logic or to interface your uC designs to external devices. Do not make only Logic based designs like some below. It would be better to use a uC, CPLD or FPGA if you are building a complex gadget Basic Digital Circuits

Digital Circuits - PDF Circuits - delabs

Digital Circuits - delabs

LM331 is a Voltage-to-Frequency Converters and 74C926 is a 4 Digit Counter. The first part of the circuit converts the amplified DC analog value from a shunt to pulses. The Second counts the pulses and Displays it on a Seven segment LED display.

Digital Timers, Counters and Clocks
  • Sequential Timer CD40xx
  • Sequential Timer 7217
  • Six Digit preset counter CD4518
  • Analog timer CD4541
  • Quad Presettable Timers
  • Digital Comparator 74HC85
  • Sequential Timer/counter 7217 with RAM
  • CD4060 and CD4020 based long duration timer.
  • Digital Timer Clock With Preset using Thumbwheel switch.
  • 1 Hz or 1 pps crystal clock using CD4060 and 32768 Hz Crystal
Mixed and Interface Circuits
  • Optical Proximity Switch
  • Profile Controller
  • Toaster timer 555
  • Quad analog input switch logic
  • Optical switch for water tap using LM555 and LM567
  • Diff input DS8830 to TTL convertor
  • Phase lock loop using 4046
  • Am hour meter for battery chargers or electroplating equipment. 74C926

Saturday, June 14, 2014

Electronic Shift Monitor

The Security Guard duty monitor below, shown in eight circuits at Digital Circuits - 1 are examples of logic circuits, i have converted them from the DOS Orcad to Orcad 9 and corrected some errors a few years back.

Electronic Shift Monitor - delabs

These circuits can be used for looking at the logic blocks or to learn. This product was built and sold to some firms many years back. Now these designs are best done with a PIC or Atmel chip. Here is the user manual

Electronic Shift Monitor ESM9000

This circuit was done with CMOS CD40xx type of ICs. A RAM was used to store the Day/Time LED Status.

This was custom made for a bank, it was to monitor the Alertness of the Security Guard. Periodically the Unit will Buzz and Flash and the Security Guard has to press a  Big Button to indicate he is awake, alert, agile and around the Unit.

In the Morning the Bank Manager will see the Security Status LEDs. All Green means fine, few Red LEDs means the Guard was sleeping or gone away from some times. All Red means Security Guard is missing. :-)

Made quite some numbers but was not profitable and soon similar lower cost clones appeared.

Wednesday, June 11, 2014

Digital Dice Cubes

Dual Digital Dice Gadget - Click the Dice Cube, Wait, It will Display a Random Result, A random generation for rolling and one for showing value.



Dual Digital Dice Cube, It will Display a Random Result for the 6 faces of the Dice, It has both a Cube Animation and Digital Readout for Two Dice. GitHub - digital-dice

Screenshot of Widget

Digital Dice

Add the Widget to your Page  Dual Digital Dice xml code