Found Active Proximity switch for DSP Card Auto Focus

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Tech_Marco
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Joined: Mon Jun 15, 2009 3:00 pm
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Found Active Proximity switch for DSP Card Auto Focus

Post by Tech_Marco »

My tech found me a special active proximity switch that works without any mechanic part. I think it's good one for being used as Auto Focus sesing on the DSP controller. This switch need 10~30V (or AC 90~250V for AC type) to power and there are five different types. I think I'll pick A or D for testing. Should have it in about 10 days

Type:
1-A:three wires NPN Normally Closed or Normall Open
1-B:three wires PNP Normally Closed or Normall Open
1-C:four wires three wires NPN or PNP (Normally Closed and Normall Open)
1-D:DC two wires, N.O. or N.C.
1-E:AC two wires N.O. or N.C.

2、Voltage:10-30V DC 、90~250V AC
3、Output current:200mA /300mA
4、Sens distance:Sn=4mm
5、Accuracy:≤5%Sn
6、Frequency:30Hz
7、Size:12mm×12mm×1mm
8、Temp:-25℃-80℃
9、Material:Copper with coating
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CapSensorSwitch.jpg
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Tech_Marco
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by Tech_Marco »

Update of this post:

I received the sample yesterday and ran a preliminary test on it. It's a pretty good device and it respond quick once a distance of ~1.5mm between an object (any object, metal, plastic..) is detected. The sensor is made of a 3 wire NPN normally open circuit and input voltage is DC 9v~36V.

I haven't tried it on the DSP card yet as I need to do more test before appling it to it, can't afford of blowing off the card. I believe that I need to setup a R circuit with two resistors of which it forms a voltage divider. It is because that the operating voltage is higher than 5V, the trigger voltage of the DSP. For example, if the input is 24V, then I need to get two resistors: 10K and 40K. So when it's inactive, there is 4.8V voltage drop across the 10K or 0V when the sensor is triggered.

Will test more later and will post more info here

Marco
Tech_Marco
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by Tech_Marco »

Update:

I talked to the tech guy and he said that there is no need to setup a resistor voltage divider and saying that I could connect the output from the proximity switch to the limit sensor input. Just power the proximity switch with the main board power which is DC24V. The open loop output from the NPN collector pin is almost the same as 24V. But once it's connect to the DSP U- input pin, it dropped to 5.6V which is safe for most TTL circuit.

Guess what, it works!

The proximity switches that I used for testing were capactiance type and it can detect most kind of materials. It can be metal or non metal. If you have RF type, then it reflection surface must be metal. I have tested two different sensors, one comes with fixed detection distance, about 1.5mm and another one is adjustable from 0 to 10mm. But the diameter of the adjstable is about twice as big as the non-adjustble.

Currently, I have 20x adjustable in stock now. Will order the fixed distance later.

Marco
gandyman
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by gandyman »

Do you have a wiring Diagram for these to hook up to the LO7 Controller for Autofocus?
Techgraphix
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by Techgraphix »

Correct me if i'm wrong, but i thought the input of the autofocus-sensor is connected to the ELZ- (Connector 9 pin 5)
These sensors have 3 wires:
Brown = +V (although they should work in the range of 6~to approx. 30V, they work fine on a 5V supply too) Can be connected to Connector 9 Pin 1
Blue = 0V (GND - Connector 9 pin 6)
Black = output (Connector 9 Pin 5)

Nowadays i use an ultrasonic sensor (UB300-12GM-E5-V1) which has a teach-in input to "learn" the correct distance. Its accuracy is very good on almost all materials, except 'felt'.. Pepperl+Fuchs makes them, but thes are quite expensive.. If you manage to score a good second hand or one from another cheaper brand, this sensors are really the finest way to autofocus.. You will also find them on the higher priced class lasers..

Kees
gandyman
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by gandyman »

Thanks. I will see about the ultrasonic sensor. I do cut felt but I would assume since it is so thin it would just sense the bed. I am going to order one today. Hook up is about the same? So looking about 300$shipped so not bad. Would I need the programmer also?
Techgraphix
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Re: Found Active Proximity switch for DSP Card Auto Focus

Post by Techgraphix »

When you lay a piece of paper on top of the felt you will have no problem and the difference is almost zero..
The connection is the same.
I use a small on-off-on switch (a tumbler with middle position). One side connected to +V, the other side to GND and the middle to the teach-in entry of the sensor.
In that way i can position it to the desired distance and give it a teach-in-pulse.. Then i set this switch back to the middle position.
On the photo, you can see this switch placed on the aluminum cableguide-support.
Ultrasonic.JPG
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Ultrasonic2.JPG
Ultrasonic2.JPG (57.96 KiB) Viewed 2320 times
Kees
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