Motorsport device, lane change, traffic signal

[scuzymoto]

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**

 

[ljcox]

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.

 

[scuzymoto]

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?

 

[scuzymoto]

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.

 

[ljcox]

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?

Yes, it can operate from 12 Volt.

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

 

[ljcox]

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.

 

[scuzymoto]

Thats fantastic. Thank you.