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Blog 555 Timers, 7-Segment Displays, Board Games, or Pocket Calculators? You Decide in the latest Project14 Poll!

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Author Author: tariq.ahmad
Date Created: 28 Jan 2022 1:57 AM Date Created
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555 Timers, 7-Segment Displays, Board Games, or Pocket Calculators? You Decide in the latest Project14 Poll!

28 Jan 2022

Op-Amps will be the Next Competition that You Decided!

Pick a theme for the March project competition by voting in our poll! Submit theme ideas for next month's project competition in the comments below.


555 Timers	7-Segment Displays

Board Games	Pocket Calculators

How are Monthly Themes selected?

Around the middle of every month a new poll will go up with themes to choose from.
Vote on the design competition you want to see next.
The poll will remain open until the middle of the following month when it's replaced with a new poll.

Top Comments

dougw over 3 years ago in reply to jc2048 +1

It simply brought the "+" key to a jack on the case. This could be wired to an optocoupler or a reed switch etc. To start it you had to enter "1" on the keypad.

Parents

jc2048 over 3 years ago

Clue as to how I voted. I bought this Commodore SR-1800 sometime in the mid 1970s. It still works on the AC adaptor, though the rechargeable nicad batteries are long gone.
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dougw over 3 years ago in reply to jc2048

That brings back memories. Back in the 70s I hacked a 4 function calculator to turn it into a lap counter for slot car racing. My TI LED calculator from that era still works, but has been hacked to run off a power supply.
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jc2048 over 3 years ago in reply to dougw

Was that using an analogue switch like a 4016 or 4066 to 'press' the relevant key? I think I can remember designs for things like stopwatches in some of the hobby magazines over here at the time that worked like that.
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jc2048 over 3 years ago in reply to dougw

Was that using an analogue switch like a 4016 or 4066 to 'press' the relevant key? I think I can remember designs for things like stopwatches in some of the hobby magazines over here at the time that worked like that.
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Children

dougw over 3 years ago in reply to jc2048

It simply brought the "+" key to a jack on the case. This could be wired to an optocoupler or a reed switch etc. To start it you had to enter "1" on the keypad.
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