Simple Robot(traffic Light) Led Project.., Helping out with a school project

So the grandson called me up a few nights ago and said he has a school project for next Wednesday.. he has to build a working Robot/Traffic light..

So i've already pulled out a few parts, Got a 555 for clock, and was looking for a 4017 Decade counter, however low/no stock and got the 4022 Octal counter..

Mostly because this has to be simple, i worked this out for the final connections.. (ignoring the 555 in Astable mode for clock)..



comments ??

BTW. Remember it has to be built/assembled by a 13 year old in class.. I got parts to build 4 units, and will sample build one for him first...

good idea on whipping one up first .
sure beats him telling you that it was a fail and yer getting lumps of coal for christmas .

man ... if you had a multi pole deck switch it would go well with the diode logic .

I was building Heathkit tranceivers at 13.... how advanced is the grandson?

His third Electrical task....

Still learning to solder....

Not my Fault Dad is a welder, and only knows steel...

You might check out this UK version (yellow both ways). It uses a 4017 (which I assume is a moot point), but also has fewer parts. And omitting one yellow is simple enough if required.

http://www.kpsec.freeuk.com/projects/trafficlight.htm

It has both schematic and stripboard layouts btw.

I originally was looking for the 4017(Stock Shortage), but got the 4022...

Also it's only more parts because doing the LED lights for both directions..

Now the issue i'm Having is that on the breadboard the output used for yellow O3(pin 7) oscillates

See this Vid
Note: I only setup the first set of lights, Second set once bugs worked out..

Also looking at the number of different example circuits using the 4017, and 4022, i see that Enable & reset sometimes is connected directly to GND, Some it only has a ~10K Pull down, and some it includes a 10uf across the pull down and VCC... So which is ideal??

Next thing, Supply is 9V (150mA) and with 0 load the Outputs pullup to ~8.6.. once load is on, the outputs pullup to ~4V.... Normal or not..

Since red/green are on at the same time, can't you just add more leds and resistors for the other view? There's no need to re-diode everything.

You right .. there is a less parts way..

Was rethinking the number of diodes and came up with this..



Might have to adjust some resistor values (R3 & R6) because of the Additional V drop on second Diode.. (maybe not !!)

but its 4 less 4148's...

However still a little quizzed to the Oscillation on Q3 output, tried another chip just in case-- Same.. Will have to Scope it...

I'm no counter wizard, but won't the 4017 circuit I linked to also work for the 4022 with minor changes (mostly re-arranging the counting outputs to end at Q7 rather than Q9)?

If so, it might save a few headaches.

.. I pretty much have done just that.. (my 555 circuit runs smooth, Adgustable 1.5hz to ~15hz) it seems the prob may be the 4022..

i'm gonna this circuit

If you say so. I'm still seeing twice the diodes and 8 pins (rather than 7) connecting the LEDs in your last diagram...

Did you use the same setup (1uF/22k) for the reset pin?

Okay so i found most of the problems...

#1) The Q3 occilation.... Hmmmm the store suplied my with self blinking Yellows instead of std yellows.. (need to find some replacements as we only have High bright reds in store)

#2) Current draw is a little high, Datasheet lists 36mA as high level current. (think i may be pulling a little more.) will use a slightly higher val resistor on the LED's..

In that circuit they using CO (Carry over) to drive the Red LED, cutting out 4, Also here in South Africa, the Traffic lights only do yellow before red, not before green...

Also because i'm doing both directions on one board, i need a extra set...

Will Upload A vid of the Proto a little later...

Right so here is the Final Proto running..

\o/ Woot \o/

BTW: found a few old yellows in the stores (Pre used, but WTF, they still work).

cool ...
pre-used = pretested .

Hehe, sabotaged by the vendor...

In that circuit they using CO (Carry over) to drive the Red LED, cutting out 4, Also here in South Africa, the Traffic lights only do yellow before red, not before green...

I think with the 4017, CO is 5 ticks. Your 4022 should be 4, and would eliminate that many diodes.

I don't think an extra set of diodes is necessary. You can connect red/green from one view to green/red on the other view following the same diode set.

Also, they get yellow both ways by combining two outputs. I think you could use those outputs separately to get yellow before red on both views.

You requested it be simple, and I've just been trying to reduce the component count. But I'm happy if you are.

Hehe, sabotaged by the vendor...

Sucks... never mind that they gave me 14 pin sockets instead of 16 pin sockets for the IC's.. Managed to swap out from the work's store...

I don't think an extra set of diodes is necessary. You can connect red/green from one view to green/red on the other view following the same diode set.

Remember that a 13 year old has to explain this circuit to the class, so the best is three lines to each set, and he can show.. this is for red, Yellow, Green.. and this one line is the common..

And the other thing is we physically going to build the traffic lights, pole's 'n all, and run a 4 core line to each pole, GND, red, yellow & green. With the 'controller' boxed to one side..

Also I want it to be easy to assemble in class, everything will be partially prebuilt, in class all he has to do is insert the chips into the sockets, connect up the wires ( color coded for convenience, Black, Red, White, Blue), and plug in the 9V battery..

Also this is the first chipped project he's doing, trying to keep the connections simple. His original idea was to simply use switches to turn on/off the 6 lights in sequence..

Project is due on Wednesday, so i will report back after then on what happened in class..

Today spent the day with my grandson, He let me know it's okay to bring it in fully built, just he has to have built it himself, No ready made Models etc allowed..

Now with the build, last night I built these Mini light posts...

shaped some veroboard andpainted it black, put the three LED's on it, and attach the 4 core cable behind.. Instant Traffic poles. ...

This morning, went over to the kids place, and sat with him so that we could build it together..

Here he is cutting tracks on the veroboard with a drill bit...


and obviously after soldering, long legs need to be clipped..


We put copies of these pics on his celly, so that he can provide proof of physically building the project to his teacher...

Time to end off...

Here is the final running project..
Note: the box is what he's taking the project to school in..

BTW: as he's explained it, most will be bringing a robot built similar to this one

Cool!

Nice job, both of you.

Right so yesterday was Project day, and my grandson was smart about it too. He made sure not to let anyone see it till it was his turn to demo..

Firstly, It was the smallest project to be handed in,(next smallest was twice the size of this one). He pulled it out, and started to describe what resistors, Diode, and IC's do, a few flashcards included.. and then turned it on, for the class to see a automatic traffic light in operation...

Well needless to say, after showing the pics of him physically building it, the Teacher gave him Full marks for the project...

The best part of it all that made him Proud, in all the years that the teacher has been handing out this project, His is the first fully automated(ie IC controlled), and first with both sets of lights, that has ever been handed in...

And of course me drilling him about what Resistors, diodes and capacitors basic functions are. as well as the basic function of the 555 and 4022 in this circuit, we was able to pull of the perfect presentation. I even gave him the schematic and Board layout printouts from the 4017 proto, so he can explain how the circuit works..

Needles to say, i have now painted myself and possibly him in a corner, and will have to better this one for the next project...

Victims of your own success...

Hopefully your grandson will develop a serious interest in electronics.