Range sensor (Urgent)

[almula]

hi everyone.
we asked to design a distance sensor with TSOP 1138. i've attached the datasheet here. the problem is that we have to sent square waves and then steady wave and so on. to create square waves i think we'll use square wave generator, but how to design this to make the square waves follow by steady wave?

can you help me to design this project?

here is a little description of project.

You may use resistors, capacitors, inductors, diodes, LEDs, IR-LEDs and op-amps. You can use maximum 3 DC supplies.

Your circuit is required to measure the distances of objects in the range 0-60 cm. For display purposes, you may utilize LEDs. At least four TSOP1138 IR sensors are required. In the range 20-60 cm receivers must be active and number should decrease as the object comes closer to the receiver in the range 0-20 cm. For
objects further than 60 cm, which is the maximum detectable range of the system, all LEDs should be off. The object, whose range will should be of size 10cmx5cm (width x
height), whereas depth is not important.

 

[ericgibbs]

hi everyone.
generator, but how to design this to make the square waves follow by steady wave?
.

hi,
Whats a steady wave.????

 

[ash20]

i think he might have meant dc??? DC light (e.g. from tungsten bulb or sunlight)???

 

[blueroomelectronics]

This is a nice steady wave.
**broken link removed**

 

[almula]

yeah i meant DC ))))

 

[wannaBinventor]

Are 555 timers in play by chance? You didn't same if transistors were in play or not, but I don't see an easy way to do it without them.

The big problem here is that you are going to activate the AGC on the TSOP if you aren't careful and it will start ignoring everything for a time. I don't understand the idea of using 4 TSOPs if they all are working at the same bandpass.

 

[almula]

if we'll use less TSOPs we will lose points. Using 8 TSOP s will give us bonus points.
I'm the second year student, and we just began to study the fundamentals of electrical and electronic engineering, so I'm not good enough to design it myself

 

[ronv]

I think the steady wave may be the time between the 38khz square wave that the sensor needs to keep the noise rejection happy. Maybe the multiple use is just to triangulate the distance??

 

[ash20]

cant we use a simple diode capacitor (in series) to make square wave come down to get dc???

 

[ronv]

IR Driver

Is this what you need?

 

[ronv]

Distance sensor

Here are some more circuits. If I understand correctly the 4 leds should come one when the "wall" gets to each distance. This is one way I think it might be done. Make sure to shield both the sensor and the emmiter from each other as the TSOP is very sensitive.
The 555 circuit is the transmitter and the other the TSOP receiver.

 

[almula]

Thanks a lot ))))

 

[almula]

how can we use just one power supply for this project?

 

[ronv]

Use only 5 volts to make the tsop happy. (like last set of drawings)

 

[almula]

how can we design it with op amps, not timers?

 

[ronv]

38khz

Not as good as the timers, but it should work. If it needs to run off of 3 volts you will need a different FET.

 

[EfeVural]

what does low mean, ground?

 

[EfeVural]

oh i god it i think low frequency led and high frequency led you mean

 

[EfeVural]

can you create the squarewave with gaptime without transistor

 

[ronv]

Yes, but the circuit won't have much power to drive the leds so you may need more circuits for your project to work.