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Project Notes

#426 Boldport 3x7 RippleTester

Using some 4000 series counters (CD4017, CD4060) to exercise the digits and segments of the Boldport 3x7.


Here’s a quick demo..



After building the Boldport 3x7 I thought it would be nice to have a simple way to demonstrate that all the segments and digit controls are working correctly - without having to do it by hand or resort to plugging in a microcontroller.

So I whipped up this circuit on a breadboard using a CD4017 and CD4060:

  • the CD4060 is configured with an RC oscillator resulting in a first counter stage (Q4) frequency of about 6 Hz
  • seven CD4060 counter stages (Q4-Q10) feed the 3x7 segment pins a-g
  • the next CD4060 counter stage (Q12) is hooked to reset, and also provides the clock pulse to the CD4017
  • the CD4017 steps through output 0,1,2 and then resets it’s count
  • the CD4017 outputs 0,1,2 feed the 3x7 digit pins A, B, C

The result is a simple pattern that runs through all combinations of segments on each digit in turn.

Note: because the CD4060 does not expose Q11 counter stage, the pattern of segments actually runs twice on each digit before moving to the next.





Credits and References

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This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.