An unusual implementation of LED traffic lights.
This is a programmable unit employing a 2k byte CMOS static RAM chip (Sony CXK5814P-35L) and a latch (74LS273 or 74HC273). A 555 timer is used as a clock and is connected to the CLK input of the latch.
This is a programmable unit employing a 2k byte CMOS static RAM chip (Sony CXK5814P-35L) and a latch (74LS273 or 74HC273). A 555 timer is used as a clock and is connected to the CLK input of the latch.
Ha Ha, Mega. Ideal for a model village (if you don't mind re-programing it every time it's been turned off)! I love it.
I did a traffic light as a mental exercise (havern't actually built the thing), and it's a lot simpler than that. It uses a 555 and a 4017 to generate the states. There is no programming involved. The key to getting different timing periods is to have different states include or not different timing resistors for the 555…
There should be a 1/3s delay between Red ON and Green ON in real life simulation.
Why have you complicated so much such a simple task?
Applause Julian… My dad built me a "play" traffic lite, when I was about 3… at about 16,, I tried making it run on its own (without a switch)…. and used 2 555 timers, and a relay to toggle one side to the other…. well, it worked, but not the way it should.. since the timing was set, both sides the same,, and also,, in the style of old time lites, never both reds on at the same time, etc., just what was hard programmed… Thanks for the great vid!
What are those components that hold the breadboard and battery wires called? They look handy!
This was a nice fun video, thanks for sharing it!
You are a genius, thats why i like your videos. 0_0
Bet you would have had an easier job simulating Australian or New Zealand systems:
green, amber, red, then back to green only again with no ‘get ready’ double light stage.
I suppose it helps drivers pay attention to cross traffic more seeing them stop for the amber.
This is exactly why I like your videos, Julian. The utter madness of doing this, and at the same time, "just because you can…" As some have said, "Is this the 1950s?" – No, it's not. It's about thinking how you can accomplish something with a given set of components. 100% from me 🙂
its fun, and boring, but interesting.. yes indeed..
Have you ever done anything with buck-boost topology? Do you know much about it?
Use a NOR gate across the red and green to trigger yellow then leave a longer period with Red and Green off to activate yellow.
There is a reason why you are getting a second LED with the yellow but can't remember off the top of my head. When I learned digital logic back in the 90's we built a traffic light project all out of logic and a rom acting as a state machine.
Hi Julian, this is NOT non-sense, ‘cause it is exactly what we all love you for: doing circuitry things the uncommon way! Carry on the great work!
Do traffic lights really go from red back to yellow before going to green in the UK?
Wow, super cool! Where did you learn about these? I'd love to try and mess around with them!
I'm thinking there was a similar micro free project kit around in the 80's using a 2732 preprogrammed with a selection of light sequences controlling 8 relays on the data lines, a few dip switches to select the upper starting address and an 8 bit binary counter for the lower address lines.