Most awful hack job REDUX

This sounds like a job well done--fostering curiosity while being safe.

Good job! Now get yourself some 555 timer chips and build yourself a traffic signal controller. Hint: The red is controlled by a simple gate, if the green and amber lights are both out, then the red is on.

Vaughn

That's a clever idea... I am definitely thinking about making a traffic controller along these lines, as I have 555 timers, as well as comparators etc. Now now, but maybe in a couple of months.

i

My first electrical project was two D cells, a bulb, and a piece of wire. I had flashlights containing those items, but putting the parts together outside of the metal case is what really mede the gears start spinning.

Good job Iggy.

Jon

Thanks Jon. Yes, I do think that having all the wires out and in the open would help him get interested. It is no longer a toy, but instead, a project.

i

You might also consider building something with alligator clip test leads, so that he would be able on his own to change things around; maybe a two-color LED or something like that. Heck, even different types of lightbulbs are fascinating at that age.

Jon

I did something along the lines, yes, with some alligator clips.

i

Great! That is very good news!

Ed

Cool.

Now for advanced versions - add series switches - add parallel ones - e.g. add logic. And & or gates...

And a diode here or there and switches to route around... :-)

In other words - Kick it up a little now and then...

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Ignoramus23281 wrote:

Yep... I want first to mount it on something, and then I will do as you suggest, add some logic, timers etc.

i

--For a little fun with AC try messing with electroluminescent wire. Input can be from about 3v to 12v, then drivers can pump it up to AC at anything from 50 to 400hz. Hard to solder, but fun to make stuff with it. I get mine from coolneon.com but there are other sources. Here's a link to some of the finest work I've seen with this stuff:

Then for the finishing touch you need to add a Conflict Monitor circuit, so if it sees Green signals in both directions it kicks off the signal controller power and defaults to 4-way flashing Red... ;-)

-->--

Do real traffic light circuits have this? Just curious.

What I am really thikning about is somehow making an array of relays that are controllable from a computer (say, USB or RS-232). So that I coudl write programs and say things like (in perl)

$relays[5]->close; $relays[7]->open;

and that would close relay 5 and open relay 7. I do not want to start talking much about it, because I want to finish my tig DC-Squarewave AC inverter project.

i

Yes.

Vaughn

Yes, but they go further. They put the intersection in flash if they detect any confliciting permissive signals -- green and amber both being regarded as permissive. A (redundant) conflict monitor is a whole lot cheaper than even one lawsuit involving an accident attributable to fault in the intersection signals.

Aside from the few remaining fixed-time mechanical controllers still in service, most controllers have a red clearance interval (all red) between all phases.

The logic of an 8-phase dual-ring controller is kinda interesting. There are a lot of conflict possibilities! Each phase is a traffic movement: 8 phases could be north, south, east, west, and 4 left-turn pockets N to W, S to E, E to N and W to S. There are a number of ways these can be arranged and sequenced in permissible simultaneous pairs.

A kid might enjoy a simple standalone more; a signal that simply does red-yellow-green on a simple intersection. When it needs to have a computer connected, seems like it's more Dad's toy then.

To liven things up further, you might add a photoelectric "pre-empt" where a fire engine or police car can pre-empt the intersection. "Who gets the police car?"

add logic.

I need toys too. Plus, I think, having some simple command based controls (such as "train forward", "lift crane", "elevator to floor

4") is a hell of a lot better introduction to computers for kids than some dumb computer games.

Which is not to say that I should not do a standalone traffic light, only to say that a computer based relay controller would be useful for almost everything.

(such as turning thermostat up remotely before coming home or some such).

Such a thing may already exist.

i

No argument there -- but perhaps some toys should just be about play.

Oh yeah. There's a lot of home automation stuff out there. The job I had after designing traffic controls in the late '70's was doing a "home of the future" demo. The computer we used in the demo house was --- a traffic controller! 8080-based PC's were in their infancy. The traffic controller was based on a Mot 6800 uP. It was rugged, reliable, had LOTS of transient-protected I/O, battery-backed CMOS RAM and a 1200-baud (!) modem.