Motorsport device, lane change, traffic signal

I work with a group of driving instructors who provide driver training to public safety.

We want a device that will do the following... contain some type of sensor that senses an approaching vehicle like a traffic counter tube or a garage door sensor type device. Then when an approaching vehicle is sensed the device randomly selects one of three green lights on a post to illuminate.

The purpose is to force the driver to make a split second lane change in order to enter the section of the course indicated by the green light.

I have built small electronic projects before but always from kits, never from scratch. I humbly ask for direction what parts I should be looking for and where. I appreciate all advice.

Ideally it would be weather proof and battery powered.

I have located a viable vehicle sensor that will output 12 volts DC. Now I just need to use that 12 volts to randonly illuniate one of three lights. Please help.

Sensor here: **broken link removed**

There are many ways that it could be done. You could use a PIC, or do it in hardware.

A simple way to generate a random number is to have a counter running continuously and, the counter is stopped when a button is pushed (or in your case, when the vehicle is detected).

You need 3 outputs, so you would need a modulo 3 counter, ie. it counts 0, 1, 2, 0, 1, 2 0, etc.

A simple hardware solution would be to use the CMOS counter 4017.

This will operate with a supply voltage in the range 3 to 15 Volt. So 9 Volt would be a good choice.

To make it count in modulo 3, connect output 3 to the reset input.

Thus, when it counts from 2 to 3, it will be reset immediately.

You will need a CMOS oscillator set to run at a frequency in excess of 1kHz. The actual frequency is not critical. I suggest you use a Schmitt Trigger package such as a 40106 or 74C14, etc. for the oscillator.

Here is one that could be modified. https://www.electro-tech-online.com/threads/need-help-with-a-little-project.15736/

Alternatively, if you want to use a PIC, then what I described above can be done in programme with some minimal associated hardware.

Let us know which you prefer (ie. hardware or PIC) so we can help further.

Thank you for your assistance. The hardware approach sounds easier. Would it work with the DC 12V output of the vehicle sensor I have above?

Also, Im no engineer but with a schematic I could probably figure it out. I have built packaged kits with my kid for fun but nothing this complicated.

scuzymoto said:

Thank you for your assistance. The hardware approach sounds easier. Would it work with the DC 12V output of the vehicle sensor I have above?

Click to expand...

Yes, it can operate from 12 Volt.

I'll draw a circuit for you and post it tomorrow.

The web site said:-

"The WR-3000 is equipped with four form “C” relays (one for each zone), and one 12-volt DC output terminal that will activate for several seconds when a signal is received"

So I have designed the circuit to activate one of the 3 lamps at random for the duration of the relay output. However, this can be delay extended easily if desired.

IC2a, b & c acts as an oscillator with a frequency of about 1 kHz. IC2 is a 40106, 74C14 or similar.

IC1 counts the pulses from IC2a. When it reaches 3, it is reset rapidly back to 0. Hence modulo 3.

When the Receiver receives a signal, the relay connects 12 Volt which stops the counter by applying a High to CE (after a short delay) and lights the lamp as determined by the counter state. If the receiver cannot output a +12 Volt signal, ie. if it can only output a gnd signal, then some minor modification will be necessary.

Thats fantastic. Thank you.