7 replies to this topic

[MattD]

I have a 6 lane gantry converted to 4 lane and it has worked fine.   A few weeks ago one of the counters started flashing random times and counting sometimes when other cars came thru the other lanes.   I did about all  I know to do, checked connections, turned off and back on and it didn't fix the issue.   I though that since it was counting when other cars went under, maybe it was sensing light from the next lane.   I put a piece of tape  next to the sensor in the gantry and that seemed to fix it and all was well.    I assumed it blocked any light coming from the next lane.    It did work correctly again.   

 

At last nights racing we had the same issue with another lane.   I tried taping, as before to make sure the only light the sensor could see was the light in it's slot.    I didn't have any success.   

 

 I checked for dirt and obvious issues, but couldn't see anything wrong.    My next step is to take it all apart and  move to a work table and check each sensor and be sure each is working as it should.       

 

 Before I do that I wanted to check if anybody has had a similar issue with lights and light sensors.  

[Ramcatlarry]

Many years ago when a lot of commercial tracks used a lighted gantry to have a 'beam' to break in the photo eye under the track, we all had horror stories about the design.  Of course, the more modern method us just isolated braid on each lane to close a switch instead of opening one.

 

1)  Spider webs and nests block the photo eye.

2) Tire dust and accumulated gunk blocks the photo eye.

3)  Photo eyes do not usually burn out, but.....never count it out or the resistor attached to it.

4)  The beam lamp is dim or burned out.

5)  A wire came loose from the wire nut. or The cat chewed through the wire.

6)  Please add your story here....

[SlotCarsten]

If the sensors are of the infra red type, then a dirty trick is to view it through your phone camera. Then the ir-light is visible as white light.
That might tell you something.

[MattD]

All the lights below the slot are bright and visable.   They are very bright.

[Dave Crevie]

If you have florescent lights over the IR sensors, the flickering of the florescent tube sometimes confuses the sensor.

Turn the ambient lights off and see if that fixes it.

[Ramcatlarry]

light from the BOTTOM...hmm...could the sensors be out of alignment over the top?  Usually receptors have a narrow angle to see.

[MattD]

I have led lights over the track, but I can turn them off and see if that makes a difference.    Nothing has changed or moved and the system has done fine for a few months.    I did have this issue with one lane  a few weeks ago, but a piece of tape (maybe) next to the sensor on the gantry to restrict it's field solved that.   At least it was fine after the tape.   Might be a coincidence that it  started working OK then.   I've tried tape and even tape over the lights in the adjoining lanes, but it hasn't made any difference.    It just reads random lap times every second or two and counts as if there were a car triggering those times.    I will keep playing with it.

 

I do wonder if the sensors in the gantry are digital and can only be read by one circuit in the main units.   Say I put the sensor for lane 6 in position for lane 4 for the gantry would it still be read correctly as lane 4 or would it's output only be read by the lane 6 counter?      I took all the gantry apart and put it back together and bench tested it completely.   then moved it all to the track.    All the sensors looked the same to me, no designation that one was any different from another.  Knowing how digital works, if each sensor puts out it's on digital signal only that address should receive it, right?       

 

My next  try will be to make sure my wire connections are good.   I used those crimp splicers to connect the small wires from the gantry to the counter.   sometimes they give dubious connections.   Maybe one is hit and miss and that is causing this to act like the circuit is made or broke every couple seconds.    

[MattD]

I have a little follow up on the lap counter reading crazy on one lane.      Last week I cut some wires and  tried to stop the counter from going crazy.   I checked connections,  plugged and un-plugged the modules, turned off and on, all the simple stuff I could do.,    I slightly  moved the sensor in the bridge to see if that helped.   Nothing made any difference.

 

I blocked the light source completely and the  counter stopped the crazy read outs.   That did let me know the sensor was NOT reading light from the other lanes.   I left the light blocked and put of those free, blue Harbor Freight flash lights on the track surface shining up to the sensor.  Then it worked correctly when I moved my  hand over the light light  source.    At least I knew it was reading correct with a strong light source.    I moved the sensor light thru  the hole in the slot and maybe got it centered a little better and everything cleared up.

 

I am assuming the light had slightly shifted in the hole and wasn't send as strong a beam to the  light bridge.     If this happens again, I think I will pull the cover off the underside and try to do a little better job of  mounting the lights.   

 

It is fixed.