Electronics project: Blind spot detector

[Luke_boorman]

Hi Everyone

I am currently studying at K college and doing an electronics course we've now got to the part of the course where we have to create our own projects.

The project that I have chosen to do is a blind spot detector like seen on some modern cars to tell you if there's someone in your blind with its primary use on motorways, on Mazda it's called RVM (rear vehicle monitoring system). because the project has to be unique and currently unavailable on the market I have chosen to make a standalone blind spot detector.

After deciding on this idea I purchased a Arduino UNO because the IC I'm going to use is the ATMEL ATMEGA 328 PU MCU as the main microcontroller, I also purchased the HC-SR04 module, I found the software for programming it with through a website however have changed most of it to include a buzzer with three states. the software side of the ATMEL ATMEGA 328 PU MCU is all done now.

The problem of which I came across next was that to create the HC-SR04 module itself, its here that I have realised how unique the project I have chosen is, I have found the circuit diagram for a SRF04 module which someone on this forum said that the system should work the same as the HC-SR04 module, but I need to some how programme the IC of which is in this circuit. the IC in question is another microprocessor its a PIC12C508. I wondered if anyone knew the programming for this IC or knew an alternative to this which information is much easier to find or has created something similar or can help in anyway. the link bellow is for the circuit diagram of the SRF04 module.

SRF04 schematics

http://www.robot-electronics.co.uk/files/srf1.pdf

the actual module

http://www.robot-electronics.co.uk/htm/srf04tech.htm

[PeterH]

I don't understand where the PIC12C508 fits in this solution. It seems to me that the sensor could be driven by an Arduino if you wanted, and I'm sure you'll find plenty of examples of people using an Arduino to do that sort of thing since they seem to come up fairly frequently. If you want help using the PIC12C508 the Arduino forum isn't a good place to ask for it, though.

[AWOL]

The other point I'd make is, would you really want to use a free-flight ultrasonic device in a safety-critical situation on a moving vehicle at motorway speeds?

[Luke_boorman]

I don't understand where the PIC12C508 fits in this solution. It seems to me that the sensor could be driven by an Arduino if you wanted, and I'm sure you'll find plenty of examples of people using an Arduino to do that sort of thing since they seem to come up fairly frequently. If you want help using the PIC12C508 the Arduino forum isn't a good place to ask for it, though.

the reason why I was looking for help about the PIC was the fact that I had found the circuit for the SRF04 module but if your saying you could directly run it from the ATMEL 328 then that will be a better solution, thanks for your help 

[Luke_boorman]

The other point I'd make is, would you really want to use a free-flight ultrasonic device in a safety-critical situation on a moving vehicle at motorway speeds?

The device that I'm making for the project for placement on a vehicles wing mirror, will have all the circuitry inside the vehicle whilst the only part that is on the wing mirror itself are the sensors, which will be encapsulated in a plastic casing that will clip on the wing mirror but is also held by fastenings around the mirror. The reason for its location on the car is that it will cover almost all the blind spots current in a vehicle. Another part will be at motorway speeds the device will be pushed in to the mirror instead of off it because of the direction of movement. 

[Grumpy_Mike]

I think you missed the point AWOL was making.
You are trying to use ultrasonic time of flight from a moving vehicle, do you see a problem with that?

[Luke_boorman]

I think you missed the point AWOL was making.
You are trying to use ultrasonic time of flight from a moving vehicle, do you see a problem with that?

the system in question will work the same as a parking sensor the only difference of which would be that it will be using separate transmit/ receive  sensors and will be for longer ranges

[Grumpy_Mike]

And it will be moving at 60mph.
Ever heard of a thing called Doppler?

[lar3ry]

And it will be moving at 60mph.
Ever heard of a thing called Doppler?

Actually, the doppler ought to even out... lower frequenct hitting the other car, higher frequency returned. I'd be more concerned with turbulence and white noise.

[Grumpy_Mike]

Only if the other car has an exact match to your speed will it even out.
Yes that as well.

[AWOL]

I must admit, it was more the wind-noise that was concerning me.

[Paul__B]

I must admit, it was more the wind-noise that was concerning me.

As well as vibration and shudder.

And range.  "Ultrasonic ranging module HC - SR04 provides 2cm - 400cm non-contact measurement function, the ranging accuracy can reach to 3mm."

So - how far is 400 cm?

[polymorph]

400cm in good conditions.