Help with simple break beam switch

Bernard

Joined Aug 7, 2008
5,784
Yes, a NO push button switch.
For shading, ' would start with 3/8 " dia X 6 " for both tx & rec., with a conical reflector for rec. Will do some checking.
 

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deuce01

Joined Sep 24, 2012
39
Ok, I think I have followed you on everything. This is what I have come up with using all of the diff plans. Sorry if its hard to see. I could not post it any larger because of the file size. One think I was not sure on was were you OR'd the out puts on u12 and u6, Is that just an addition or does it replace what you already have coming off of them back to the false start going thru 16 and 18? So your thinking 3/8" on shading? Something just large enough to be able to place the IR in the end of. So something the size of an ink pin sleeve? Would the NO switch be placed inline somewhere in the W loop?

 

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Bernard

Joined Aug 7, 2008
5,784
I was undecided whether to OR or AND U6 & U12 outputs for resets [ W ]. I said AND & drew OR, but will leave it as OR. This is an addition which replaces the W near U18-2. A NO PB SW can be added between +Vcc & U13-11.
Do not forget to add power supply filter caps , 100 μF & some 1/10 μF.
 

Bernard

Joined Aug 7, 2008
5,784
I reviewed your beautifull color-coded schematic & found only 2 errors; there is an extra unlabled cap at U19-2, & U5-3 goes to U4-13, with no branches, U12-2 goes to U6-2; also might drop extra W at top of page, it was an output, now replaced by W at U13-12, a reset output.
 

Bernard

Joined Aug 7, 2008
5,784
Back to thinking about beam break, just incase the kits do not work out, or as possible replacement. A Cd-S, LDR, looks promising; 1/4 in dia, 1M dark, less than 1K light. Used 27K from +5V to cell, other side ground, cap, .01, coupling to 200k load & scope. Transmitter 555 @ 250 Hz driving bright white LED, about 20 deg, 10,000 mc @ 20 mA 50 % duty cycle. Ambient lighting, 90 deg angle, @ 4 ft from 60W equiv. CFL. With 1 in dia. 4 in focal length lens in front of LED, detected range better than 15 ft, with nice clean 60 mV, PP, signal; with some shading, even better. A white or red LED is a lot easier to aim than IR. One 555 will drive all of the LEDs on one lane. Think it is worth testing outside ??
 

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deuce01

Joined Sep 24, 2012
39
Sounds good to me but I did not understand half of what you said. But if you think it would work good I would be willing to give it a shot with your direction. The IR kit claims to have an operating range of 3' to 13' feet. So I would go with 10'-11' to be safe. That is wide enough but wider would be better. The 15' range you are talking about sounds good.
 

Bernard

Joined Aug 7, 2008
5,784
Back to drawing board: Packaged ckt. enough to be semi portable with final test good at 20 ft in brightly lit rooms; outside early evening range fell to 2 ft. Back to laser or IR?
 

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deuce01

Joined Sep 24, 2012
39
Back to drawing board: Packaged ckt. enough to be semi portable with final test good at 20 ft in brightly lit rooms; outside early evening range fell to 2 ft. Back to laser or IR?
Well, it was worth a shot. Looks like it will be IR if I can get the shading down. If not, I may have to look into the laser. The pin point accuracy would be great for not having to worry about the shading but make it a pain for aiming. And the price of the unit is a lot more and then you have to buy a cheap laser pointer too. Thanks for testing Bernard
 

Bernard

Joined Aug 7, 2008
5,784
IR needs more than IR light, the receiver needs optical filtering, so my next approach is to use a narrow beam IR emitter, 6 deg with added plastic lens, and IR transistor with 875 to 1000 nm filter. If there is the posibility of having a communication link across the lanes, then might put Rx- Tx -Rx in center, with onr receiver on outside; this would increase spacing to two ft, 8 deg, rather than the now one ft @ 4 deg. Parts went on order today for one set. Fingers crossed.
 

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deuce01

Joined Sep 24, 2012
39
Having a communication cable running across the lanes will work if that is what we have to do to be able to get 3 units working within the 24" span. Its not Ideal, but will not be a problem. The communication link, could it be something like a Cat 5 phone line and would I be able to power the units on the outside lane with this link? I would have to run the line 30' to 40' to make is safely around the lane and keep it from being drove over. So a cheap phone line would be nice.
 

Bernard

Joined Aug 7, 2008
5,784
Cat 5 cable is 24 ga so only .02 Ω/ft, so for round trip of 80 ft @ 100mA only loss of about 2/10 V. See no problem with cable.
 

Bernard

Joined Aug 7, 2008
5,784
Preleminary test looks good: IR emitter, Vishay VSLY 5850, +- 3 deg 1/2 pwr, contained beam to about 8 in. with 28 mm X 120 mm lens; so all Tx on one side. Detector- Vishay TEMT 1020, surface mt. 730-1000 nm, 15 deg. Is a little more sensitive to day light than hoped for, but still detectable at 15 ft. Tests were without modulation & reduced IR current; detector- analog Ω meter on 100 Ω range.
 

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deuce01

Joined Sep 24, 2012
39
15 ft in sunlight? Sounds like the first test went very well. If I can get 10' to 12' i'll be very happy. I'm sure the closer they are, the less the beam spreads too. I have been looking at the IR emitter and detector you tested are able to find them with out a problem. But as far as the 28 mm X 120 mm lens, I have never been able to find any. Could you post a link some time to some lens? My curiosity has got the better part of me.
 

Bernard

Joined Aug 7, 2008
5,784
Curiosity got the best of me also, so I ordered 3 sets of plastic lenses, 10 in each of 3 sizes, from Anchor Optics. If successfull that's 8 for you & 2 for me of one set, if you wish. For receivers, am using conical reflector made from shiny Al tape. ' need to make a portable receiver for modulated outdoor test, maybe today, but bowling comes next.
Side note: Un plugged + battery lead from Tx & put it into unused hole to keep from flopping around & gitting in trouble; later smelled a strange smell- checked stove- nothing- back to library & re checked, ah- battery box hot, empty hole not so empty, solid ground. One battery cooked beyond yse, battery box was repairable. Also made a mis connection with Tx- LED ended up across battery, beeing IR- did not see dying flash.
 

Bernard

Joined Aug 7, 2008
5,784
3 PM Tucson, outside in partial shade Rx facing West; moved Tx back from 5 ft to 20 ft & still detecting but pointing getting touchey. Tx, VSLY 5850. 555 & 2N3906; Rx, TEMT 1020, 1/6 th 4049 IC, 1/2 LM393. N0 relay driver untill operating V desired is established. 3 IR emitters can operate from one 555 with either 9V or 12V supply. I've run out of time for today.
 

Thread Starter

deuce01

Joined Sep 24, 2012
39
That sounds great! 99% of the time I will be using this at dusk or even after dark under stadium lighting. So it sounds like this setup will work great for my needs. I really like the idea of running 3 emitters from one circuit. Its a lot better than having 3 different IR emitters on the outside of each lane.
 

Bernard

Joined Aug 7, 2008
5,784
Here is the test ckt. used: Think I would use 12V supply for relays & regulate to 9V for logic ckts. On Tx, would change R1 to 10k, add a.1 cap to 9V supply & add two more LEDs, adjusting R5 for 75 mA. For Rx, could drop R9 down to around 100k, for faster bleed off of C6.
Do you have an O-scope available? Also, what part of the world are you in?
 

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deuce01

Joined Sep 24, 2012
39
Thanks again. The circuit looks good. Unfortunately I do not have access to an o-scope. I live in VA. You say you would use 12v for relay and 9v for logic circuit. So does that mean everything but the output side of the relay?
 

Bernard

Joined Aug 7, 2008
5,784
First for corrections: Inputs to U6 are reversed, junction of R10 & R11 go to pin 2, R9 to 3, the + input, 2 is -.
With R1 at 10k, duty cycle is 20%, LED current pulses of 50μs, or frequency about 4kHz. Thumbnail is simple IR detector used to plot IR beam width.
Our prints show relays directly driven by 555's, OK for 100 mA or less. 12 V relays seem to be more readily available. My pref. is for seperating logic V supply from relay V supply which means using drivers for relays. Select relays & we will go from there.
 

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