How to build a Distance Sensor ??

Hiya there
i'm an electronic student in the UK,it's my second year and i've asked to build a distance sensor, so it could be fix in a remote car to detects the distance while the car in the revarse state.
as my insturactor told me that i need
1- 555 timer
2- CD4089
3- CMS
4- Infrared
:shock: :shock:

it will be work on three type of Frequncy
1 khrs for 1 meter
5 khrs for 2 meter
10 khrs for 3 meter

so please if anyone has an idea hope he can help me

All here at this site, will glad to help with your education...
just a couple of quick questions to get us started
1> what is CMS ?
2> are u sure he said an infra red rangefinder?

What does khrs mean? It appears from your drawing that the system has 3 detection distances, 3 meters, 2 meters, and 1 meter. When the object is 3 meters away, one sensor receives the reflection, when it is 2 meters away the second sensor receives the reflection, etc.
The system is very simple but there are some "gotchas".
1. The object has to be reflective.
2. The beam has to be narrow enuf that only one sensor "sees" the reflection.
What progress have you made?

I just looked up the CD4089, it is a binary rate multiplier. It escapes me how or why you would use it for this simple project. I suspect you do not understand what is wanted, at least I don't.