I'm slightly confused, is there to be 3 curtains or just 1 ?
Are there to be any hands smaller than 4 cm ?
OK- just one curtain 300 mm X 400 mm.

 

I'm slightly confused, is there to be 3 curtains or just 1 ?
Are there to be any hands smaller than 4 cm ?
OK- just one curtain 300 mm X 400 mm.

Hi. Why 3 curtains? The number of sensors/curtains does not matter. The only thing that does matter is that I have absolutely no blind spots across the whole 2D space (300x400mm). The box will be 3D but as long as 2D space is fully covered, I do not need to worry about the 3rd axis since it should be impossible for the person to put his hand through the hole without triggering the sensors

 

The 10 each of items in post # 18 should be here next week. Will see if is possible to put all Tx on one side & Rx on other.

 

The 10 each of items in post # 18 should be here next week. Will see if is possible to put all Tx on one side & Rx on other.

Please make sure tell me what are your results. Thanks in advance

 

Boy did I screw up- the WP7--- 5 mm Infrared LED turns out to be an emitter but the VSLY5850
is a real jem. A quick look with a 3 mm 940 nm transistor looks like post # 7 will work with 4 0 mm spacing.
No time today, be back Monday.

 

I get excellent results using a single emitter and receiver diode in an IR reflectance circuit.
The diodes are mounted side by side and the receiver diode picks up the IR reflected from a hand when it enters the box.
Similar circuit as those "Avoidance Sensors".

 

I get excellent results using a single emitter and receiver diode in an IR reflectance circuit.
The diodes are mounted side by side and the receiver diode picks up the IR reflected from a hand when it enters the box.
Similar circuit as those "Avoidance Sensors".
View attachment 232671

Thats great. Could you tell me what Emmiter and what receiver have you used?

 

Could you tell me what Emitter and what receiver have you used?

Emitter is a Vishay TSAL6100, receiver a Vishay BVP10NF.

 

I made a new U frame with holes on 30 cm sides, Tx on one side drilled 4.83 mm #11 drill, spaced 3-
4-4-4-4-4-3 cm; Rx matching holes drilled with #10. Really one hole short from a change in mounting.
As I had no 840 nm Rxs, used a single broad wave Si detector moved from hole to hole & as a wand to
plot peak output. Two Tx s were off enough to need a small adjustment.
On circuit drawing, U1 is 1 of 8. and could be 4 groups of 2 in series if using 5 V supply. Or if using
a 12 V supply ( ICs to match ) 2 groups of 4 in series.. U2 might be:
First choice, SFH 313 FA, 870 nm, 20 deg, 5 mm, 10 ea. @ US $ .45 digi-Key.
2 nd, QSD 123-ND, 880 nm, 5 mm, 24 deg.
3 rd, VEMT 2020 gull wing SMD, 880 nm, 30 deg,

 

I bit the bullet & ordered 10 - SFH 313FA's

 

Thanks for the response. I am having some trouble understanding the circuit.
If I understand correctly:
U1 - Emitter
U2 - according to what you said is a receiver
U3 - NAND gate , I do not fully understand what is the main use of this IC in this circuit
U4 -IC's (A,B,C,D,E,F) I assume are all the same? From the part number it looks like they are level shifter, also do not understand what is the main point of this IC in this circcuit and why so many.
U5 - Just an indication LED I assume.

Is this the circuit for 1 Emitter/Recevier pair? If you want to have 10, you multiple this circuit by 10?

 

zazas321 I don't think you need a light curtain for this project. The circuit I posted in #26 should meet your requirements with that single circuit. I would highly suggest that you try it out before committing to a light curtain.

 

zazas321 I don't think you need a light curtain for this project. The circuit I posted in #26 should meet your requirements with that single circuit. I would highly suggest that you try it out before committing to a light curtain.

I do not understand how can it possible work in a 400x300mm box without any dead zones? If I put my hand in very top left or very top right corner of the box there is no chance a single sensor is going to pick that up. Sure it will pick up a signal if I put my hand below the sensor, but that is not always the case in my situation. A hand can go in any possible way and I must ensure that the extreme corners(top left, top right, bottom left, bottom right) are also covered
This is the problem I am going to have:


I have not yet found an IR sensor with an angle of 180 degrees which means I am going to have dead zones on the corners

 

it should be impossible for the person to put his hand through the hole without triggering the sensors

I was under the impression that the front of the box has a hole where you put your hand through like in the sketch?

 

U1- Tx, transmitter, emitter, VSLY 5850
U2- Rx, receiver, IR detector, SFH 313FA
U3, 8 input NAND, one input for each U1-U2 pair. Output from U2's is normally hi,; if all inputs are hi
then U3 output is lo. If any input is blocked then U3 goes hi. Output hi's are counted but how they are counted has not been specified. U4 just one example of a LED output.
U4 has 6 inverters in the IC, 74HC4049. For different supply V , then can use 4049.
If more than 8 inputs are required any number can be built from NAND-NOR- NAND IC's.
To select spacing, might try placing strings across a box & see if you can insert a hand without touching a string ?
R2's are selected to be as low as possible but give at least 4 V out when U2 is illuminated then use highest value for all 8 -10 beams.

 

I was under the impression that the front of the box has a hole where you put your hand through like in the sketch?
View attachment 232984

No. That was just my poor representation of a human hand entering the box in the middle. However, a human hand might go in the box in any way possible.

 

U1- Tx, transmitter, emitter, VSLY 5850
U2- Rx, receiver, IR detector, SFH 313FA
U3, 8 input NAND, one input for each U1-U2 pair. Output from U2's is normally hi,; if all inputs are hi
then U3 output is lo. If any input is blocked then U3 goes hi. Output hi's are counted but how they are counted has not been specified. U4 just one example of a LED output.
U4 has 6 inverters in the IC, 74HC4049. For different supply V , then can use 4049.
If more than 8 inputs are required any number can be built from NAND-NOR- NAND IC's.
To select spacing, might try placing strings across a box & see if you can insert a hand without touching a string ?
R2's are selected to be as low as possible but give at least 4 V out when U2 is illuminated then use highest value for all 8 -10 beams.

Thanks for clarifying. I am still not certain about this part of the circuit:


Since there is only 1 pair of emitter/transmitter, why 2 of the data pins are used? Perhaps you could show a schematic for 2 or 3 pairs of emmiters/receivers please

 

Does this help ?
'Will recompute R1, R2 when Rx's arrive.
In my test rig, beams are horizontal, less trash pickup & fewer sensors, 7 vs 9.

 

Yes thank you very much!

 

The SFH 313FA 's arrived but have low sensitivity so back to RPT-38PB3F 3mm +- 36 deg or surface mount VEMT2000X01CT which both work well but I only have one each. With Tx all on one side, Rx on other still works with small adjustment on Tx on some.