Post by thread:Object Speed Counting in sunlight.

Suggestions anyone? I have been monitoring mail traffic for IIR, Laser diode or Ultrasonic suggestions that my be able to solve my problem. I need to detect the speed of an object 2 - 5 feet from the sensor mount. Sensor is mounted upward looking at the sky. My thought was to use two ultrasonic sensors to detect a pulse width to determine the time the object was within the cone. Range data is secondary if at all. Need to be inexpensive - doesn't it all.... Suggestions / contacts are greatly appreciated... Thanks Mike Control System Research

<Mike Chaloupka writes in part> >I have been monitoring mail traffic for IIR, Laser diode or Ultrasonic suggestions that my be able to solve my problem. >I need to detect the speed of an object 2 - 5 feet from the sensor mount. >Sensor is mounted upward looking at the sky. Why not use the Sun's IR? I have no idea if this would work; but, adjust the bias on an IR detector until it just trips a Schmidt trigger in open sunlight. When the object passes overhead it will (presumably) obscure the sun. Putting a second detector in the line of travel will give a second pulse that confirms the validity of the first one and could be used for speed calculations if the geometry is right. Granted it's downright ugly, but it sure is cheap <g>. Cheers, Win

On Thu, 12 Nov 1998, Mike Chaloupka wrote: > I need to detect the speed of an object 2 - 5 feet from the sensor mount. > > Sensor is mounted upward looking at the sky. The optical way is easy, using a CW light source in the night and the sun in the day, but one uses more than one sensor (more like a matrix - minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing and can tell which way the object is passing, also has an early failure indicator built-in (sensors won't fail together unless someone paints them over very quickly <g>). I did something similar for a protection device on an exhaust chimney and I used 4 Al. tubes of different lengths in a pipe-organ style mount with glass windows and CdS photoresistors at the bottom connected to a LM324. The LM324 was connected as adaptive AC amplifier (to remove DC bias). The light was a parlight and was on all the time with a current sense resistor in one of the return wires. Outputs went to a Z80 based controller that also did other things. hope this helps, Peter

Thanks Peter for the tip. Any suggest regarding the light source. I though of using an EGG laser diode / receiver but total component cost are toooo high. Regarding the photoresistor - any particular kind? Did I mention the projectile my be travelling upto 100mph and has a width 4-5 inch circular & 19 inch long... Have you or anyone else listening hear dir MIR Mircropower Inpulse Radar technolgy. FCC doesn't like it yet buy companies have spend a lot for the license to use the technology. I understand it will revolutionize speed & object sensing since the entire circuit (transmitter /receiver) is possible under $50 Mike >>> "Peter L. Peres" <spam_OUTplpTakeThisOuTACTCOM.CO.IL> 11/13 5:34 AM >>> On Thu, 12 Nov 1998, Mike Chaloupka wrote: > I need to detect the speed of an object 2 - 5 feet from the sensor mount. > > Sensor is mounted upward looking at the sky. The optical way is easy, using a CW light source in the night and the sun in the day, but one uses more than one sensor (more like a matrix - minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing and can tell which way the object is passing, also has an early failure indicator built-in (sensors won't fail together unless someone paints them over very quickly <g>). I did something similar for a protection device on an exhaust chimney and I used 4 Al. tubes of different lengths in a pipe-organ style mount with glass windows and CdS photoresistors at the bottom connected to a LM324. The LM324 was connected as adaptive AC amplifier (to remove DC bias). The light was a parlight and was on all the time with a current sense resistor in one of the return wires. Outputs went to a Z80 based controller that also did other things. hope this helps, Peter

Hosfelt electronics (http://www.hosfelt.com/) has hand-held laser pointers for as little as $10.95 USD, you could adapt one to a "wall wart" power source, I'd guess. Some decent prices on other goodies for PICers, too, there. White LED's pricing looked pretty OK, for one. Inquiring Minds wanna know: What in the world's that projectile? Are you making a "Poor Man's Howitzer" here or something? <G> Mike Chaloupka wrote: > > Thanks Peter for the tip. Any suggest regarding the light source. I though o f using an EGG laser diode / receiver but total component cost are toooo high. > > Regarding the photoresistor - any particular kind? > > Did I mention the projectile my be travelling upto 100mph and has a width 4-5 inch circular & 19 inch long... > > Have you or anyone else listening hear dir MIR Mircropower Inpulse Radar tech nolgy. FCC doesn't like it yet buy companies have spend a lot for the license t o use the technology. I understand it will revolutionize speed & object sensin g since the entire circuit (transmitter /receiver) is possible under $50 {Quote hidden}> > Mike > > >>> "Peter L. Peres" <.....plpKILLspam@spam@ACTCOM.CO.IL> 11/13 5:34 AM >>> > On Thu, 12 Nov 1998, Mike Chaloupka wrote: > > > I need to detect the speed of an object 2 - 5 feet from the sensor mount. > > > > Sensor is mounted upward looking at the sky. > > The optical way is easy, using a CW light source in the night and the sun > in the day, but one uses more than one sensor (more like a matrix - > minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing > and can tell which way the object is passing, also has an early failure > indicator built-in (sensors won't fail together unless someone paints > them over very quickly <g>). > > I did something similar for a protection device on an exhaust chimney and > I used 4 Al. tubes of different lengths in a pipe-organ style mount with > glass windows and CdS photoresistors at the bottom connected to a LM324. > The LM324 was connected as adaptive AC amplifier (to remove DC bias). The > light was a parlight and was on all the time with a current sense resistor > in one of the return wires. Outputs went to a Z80 based controller that > also did other things. > > hope this helps, > > Peter

On Sat, 21 Nov 1998, Mike Chaloupka wrote: > Thanks Peter for the tip. Any suggest regarding the light source. I > though of using an EGG laser diode / receiver but total component cost > are toooo high. A parlight is a parlight. Made by GE, available through any party/show lighting supply. > Regarding the photoresistor - any particular kind? I used plain CdS photocells (the uncased version - a disc with 2 terminals protruding on the back). > Did I mention the projectile my be travelling upto 100mph and has a > width 4-5 inch circular & 19 inch long... No you did not. This may be a problem... My pipe organ had 2/3 tubes so it's up to you to calculate how long they will be obscured / lighted, each, at 100 mph and make sure that your electronics will be up to the task. Makes me wonder what you're counting ?! Peter