• This topic has 8 replies, 3 voices, and was last updated 1 week ago by Guenni75.
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    • #7499
      Guenni75
      Moderator

      Hi everyone,

      since years I was quite confused about a Lectron block #8100434 from the 1970 catalog. Visiting Edzard Timmer and looking around his Lectron parts I found a couple of these blocks:

      (Collection M.P.)

      Visiting later Mr. Gürth he told me, that he made all these blocks and gave it to Mr. Timmer and Mr. Birett for experiments (one example is in his booklet “Funktionmodelle”!).

      Mr. Gürth also made some traffic light blocks with Lectron:

      (Collection M.P.)

      Now I was curious and searched in the internet for a common application to use it today and found an exercice of the University of Münster (Germany) for a traffic light problem for students (and another similar exercise for schools class 9…11 with a more complex problem to integrate the pedestrian traffic lights, too!).

      My version is hand-wired diode matrix version with a 4-step-switch for the 4 basic functions, including a day/night/emergency switch for blinking light for the non-main street users:

      The solution schematic (from University Münster) is as follows, including my blinking circuit:

      This block / circuit is still in my “Incubator” (so-called by the Electronic Magazine ELEKTUUR / ELEKTOR) for automatic switching by ICs (CD4017, NE555, …) with different durations for the 4 phases and with automatic day/night start of the yellow blinking lights…

      Any – realisistic / minimalistic – idea?

      Günther

       

      • This topic was modified 2 weeks, 6 days ago by mwpeters75.
      • This topic was modified 2 weeks, 6 days ago by mwpeters75.
      • This topic was modified 2 weeks, 6 days ago by mwpeters75.
    • #7523
      LectronFan
      Participant

      Hi !

      Well, this is a real life situation.

      However, I’m still dazzled how your phases work. Our traffic lights go from green to yellow to red. Yellow is never on together with red. Perhaps this is in other countries the way traffic lights work.

      Anyway, I will think about an automatic way for the lights. This can also be achieved by using logic gates. The diode matrixes were used before logic chips became widely used.

      I have a Korg mini pops drumcomputer (from around 1970). It uses only analogue components including a complex diode matrix for driving the rhythm patterns.

      Many greetings

      • This reply was modified 2 weeks, 4 days ago by LectronFan.
      • This reply was modified 2 weeks, 3 days ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #7528
      mwpeters75
      Keymaster

      The traffic lights here in the US are like Belgium’s.  

    • #7529
      LectronFan
      Participant

      Hi,

      Well, with our Lectron set, we can build an easy yet working principle of traffic lights like the ones used in my country. The circuit is build around a 3 stage multivibrator. By choosing the appropriate values of the capacitors, we can reach the correct timings. In my circuit the timing is relatively short and only for demonstration.
      The leds for the crossing roads should be inversed by using inverters.

      Here is picture

      Many greetings

      • This reply was modified 1 week ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #7550
      Guenni75
      Moderator

      Hi all,

      yes – may be that not all countries have 4 phases, but from my point of view it is very helpful. You never have an interrupt-free look to that lights, and if you see only a yellow light you never know: should I stop immediately – or can I drive into the crossing within the next second… that’s a BIG difference!

      The following overview may help  –  that are snapshots (in German) but illustrates what I said above:

      Frank: your solution is a good first step for countries with 3 phases, nevertheless I will wait for the right inspiration – thank you so far!

      Best,

      Günther

       

    • #7559
      LectronFan
      Participant

      Hi all,

      It was a challenge to build a working traffic light the way Günther described and thanks to the versatile Lectron system, I found a solution.

      The circuit fits on a A3 mounting board and has 3 wire bridges to reach blocks far away from each other.

      It was a bit tricky to build since I had 2 new unused bad transistors. Luckily I could replace these by opening the cubes. They worked but had very low leakage which made it hard to find out why the circuit wasn’t performing well.

      And it was also a challenge to actual make a practical setup with all these crossing wires and T wires. But it works !

      The lights go from green to yellow to red to yellow + red and then back to green.

      I used about 6 transistors and 1 mosfet (I ran out of NPN transistors!) and 4 diodes.

      I will publish the circuit soon, it was a bit hectic all around here lately 😉

      Greetings

    • #7588
      Guenni75
      Moderator

      Hi Frank,

      that sounds sensational! I can’t wait for your solution!

      I am sure that you know this “little helpers”:

      It’s always good to have these if a special transistor – ore whatever part – is not available as a Lectron block… therefore purchase if you see some of these…

      Best,

      Günther

    • #7598
      LectronFan
      Participant

      Hi all !

      Great idea Günther to look out for these Lectron blocks with connectors for components.

      And as promised, here the setup for the 4 phase traffic light.

      To operate, connect the power (battery), set the switch in upper position and wait till all lights are out.

      Then toggle the switch down and watch the sequence of the traffic lights !

      I assembled the circuit and made use of many blocks but still 3 cable connections have to be made.

      By assembling, I stumbled across a problem that  T3 and T4 were not working in sequence. By adding resistor R10 (47 Ohm), the circuit works flawlessly. This resistor pulls the base voltage of T4 higher so that no false triggering can occur anymore.

      By changing values of the 100µF capacitors and 100K resistors, the timing can be altered.

      You can always use a NPN transistor for T5 (I had only 6 NPN transistors 😛 )

      Here’s the setup :

      Many greetings

      Traffic Lights

       

      • This reply was modified 1 week ago by mwpeters75. Reason: Changed font and size styling for easier reading
    • #7634
      Guenni75
      Moderator

      Wow – that’s absolutely great! I will build this circuit and try the durations and parallel lights (crossing) as soon as possible – thank you, Frank!

      Best,

      Günther

      • This reply was modified 1 week ago by mwpeters75. Reason: Changed font and size styling for easier reading
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