# Automatically count the number of times an object passes a specific location

#### Cj51ane

Joined Jul 5, 2021
4
Hi, I am looking some help.

I organise a fundraising event whereby a sports club run a marathon. This is done in a relay format, completing 421 laps around a 100m circle. A relay baton has to be carried around all these laps

I was wondering if it is possible to use some kind of circuit to count the relay baton as it is carried around the laps.

Any help would be greatly appreciated.

Ciaran

#### Irving

Joined Jan 30, 2016
3,810
I assume you mean an automatic, non-contact solution?

The obvious solution is a low power transmitter in the baton and a receiver at some location on the circle. As long as the transmission is low enough power to only be 'heard' when the baton is near the counting station it will work...

#### Externet

Joined Nov 29, 2005
2,184
RFID for the baton passing by a gate + counter ?

#### Cj51ane

Joined Jul 5, 2021
4
I assume you mean an automatic, non-contact solution?

The obvious solution is a low power transmitter in the baton and a receiver at some location on the circle. As long as the transmission is low enough power to only be 'heard' when the baton is near the counting station it will work...

Thank you so much for that information! Yes an automatic non contact solution is exactly what I need.

Where would I get the low power transmitter and receiver you mentioned?
Thanks again!

#### Cj51ane

Joined Jul 5, 2021
4
RFID for the baton passing by a gate + counter ?
Thank you very much for your help. Where would I get the RFID? And what sort of gate would I need? I have seen plenty of counters available.

Thanks again!

#### Externet

Joined Nov 29, 2005
2,184

#### drc_567

Joined Dec 29, 2008
1,156
The difficulty with the RFID system appears to be finding a specific RFID reader and card pair that operate at a practical distance, maybe several meters. It seems that many of the low-end RFID systems only work at a distance of inches or centimeters.

#### Irving

Joined Jan 30, 2016
3,810
Thank you so much for that information! Yes an automatic non contact solution is exactly what I need.

Where would I get the low power transmitter and receiver you mentioned?
Thanks again!
The RFID solution is a practical one, but to advise further we need to know where you're based and what's your reasonable budget? You may be able to rent most of what you need.

Also, will you have mains electricity or a generator, or will this have to run on batteries, in which case how long is the event expected to last?

#### Cj51ane

Joined Jul 5, 2021
4
The RFID solution is a practical one, but to advise further we need to know where you're based and what's your reasonable budget? You may be able to rent most of what you need.

Also, will you have mains electricity or a generator, or will this have to run on batteries, in which case how long is the event expected to last?

Many thanks everyone!!
I am based in the UK. I'm not sure how much these items would cost. I'd it was more than £50/£100 then I wouldn't go ahead with my idea. Is this budget realistic?

I would need the RFID to work at a distance of 1 - 2 metres. Currently I am running a timing clock of a 12v car battery using a 12v to 240v converter. Would this work to power the RFID?

#### Irving

Joined Jan 30, 2016
3,810
OK, well yes, the RFID solution, even to hire would be a few £100.

OK, here's a very simple solution. Make up a couple of vertical wooden gates/supports*** like in post #6 above about 2m apart and fit one of these beam breaker detectors on the inside faces at waist height. Both sides are powered directly from the 12v battery. Then all you need is a counter - three of these nice big LED numbers driven by an Arduino microcontroller and one of these driver boards and some other minor bits, wire, etc. and a transparent plastic box to mount the display etc in and make it all tidy & waterproof.

A few lines of software and job done.... total cost for parts ~£60, plus the wood & case. Probably around the £100 mark if you're handy with a saw/drill/etc...

Do it right and can be reused year by year...

*** or maybe a pair of cheap tripods...

#### MisterBill2

Joined Jan 23, 2018
17,870
Actually, the beam break system and a digital counter and NO ARDUINO needed. Then the package could be assembled and be fairly durable and rugged enough to keep functioning for the duration. The counter could be either electronic or mechanical, both types are common.

#### Irving

Joined Jan 30, 2016
3,810
Actually, the beam break system and a digital counter and NO ARDUINO needed. Then the package could be assembled and be fairly durable and rugged enough to keep functioning for the duration. The counter could be either electronic or mechanical, both types are common.
True, though off the shelf large digit display counters are silly expensive (unless you can find a cheap one, I looked and couldn't find anything < £200 just for the display). I was postulating a cheap, easy to make. display with 4" high digits that can be seen from a distance and would look very professional.

Agreed, the Arduino isn't the only way and could be replaced with a 555 to do a bit of signal conditioning/debounce, MC14533 counter, MC14511 7-seg decoder, ULN2003 seg driver, 3 x 2N3906 transistors and a dozen resistors, etc. but that's a much more complicated and probably more expensive build.

#### drc_567

Joined Dec 29, 2008
1,156
The main advantage of an RFID design is that the accumulated circuit iterations for each team and associated RFID tag could be tabulated on an Arduino, or similar microprocessor. It seems that to achieve the RFID design method, in an economical manner, it would be necessary to make the final runner on each circuit make a special effort to pass the baton/tag by a particular point, where the RFID reader is located, so that the baton would be within the reader proximity and the total circuit number for each baton could be incremented. This requirement would be a change from the usual marathon routine, and may not be practical or acceptable.

#### MisterBill2

Joined Jan 23, 2018
17,870
OK, here is a cheap version: Use the beam-break sensor and the contact closure connection is wired to the button on a computer mouse. The mouse is plugged into an older laptop computer with a simple program to count mouse clicks and display the number on the screen. The display can be as big as the screen, and it would also be possible to display the lap time as well. Then the expense would be much less. And an older computer mouse, not a laer mouse but one with a mechanical switch, should be easy to find.

#### Irving

Joined Jan 30, 2016
3,810
The main advantage of an RFID design is that the accumulated circuit iterations for each team and associated RFID tag could be tabulated on an Arduino, or similar microprocessor. It seems that to achieve the RFID design method, in an economical manner, it would be necessary to make the final runner on each circuit make a special effort to pass the baton/tag by a particular point, where the RFID reader is located, so that the baton would be within the reader proximity and the total circuit number for each baton could be incremented. This requirement would be a change from the usual marathon routine, and may not be practical or acceptable.
I'm guessing, since its a 100m circle (hence 421 laps = 42.1km) and only around 20-40s a lap (approx 2.5h - 4.5h marathon) that one runner completes several laps and there would be a baton handover somewhere away from the 'gate'. I didn't get - from the original description - that there was more than 1 team; there's no requirement to track more than one baton. That makes a beam breaker solution feasible.

Joined Jan 15, 2015
7,458
I am going to suggest RFID and here is why. When we travel by car we use what is called EZ Pass. My receiver transponder is clipped to my windshield and works easily over several meters and is powered up by the received signal meaning no batteries to fail. My unit has a code unique to me so if you have several runners passing off a baton each baton will have a unique number or code. You can not only count laps but time laps for each individual runner as well as get a total elapsed time. The system also allows fast data pickup, faster than the runners will be traveling when a baton is handed off. We just roll right through toll booths in our designated lanes.

There is also, as mentioned a beam breaker circuit. A simple Google of "Garage Safety Beam" should bring up some examples and nice thing is most resist false triggering from UV light.

Ron

#### MisterBill2

Joined Jan 23, 2018
17,870
The stationary portion of that easy-pass sensor costs more than the cars driving past it. Rather out of the budget for this project. That is why a beam break sensor generaating a mouse click for a slightly older laptop computer could work, with the laps showing up on the screen. A much less costly way.

Joined Jan 15, 2015
7,458
The stationary portion of that easy-pass sensor costs more than the cars driving past it. Rather out of the budget for this project. That is why a beam break sensor generaating a mouse click for a slightly older laptop computer could work, with the laps showing up on the screen. A much less costly way.
I never said we needed an exact duplicate. How wide is a track running lane? I also mentioned a beam break. Cheap and easy a garage door safety system. RFID was just an example using EZ Pass.

We used RFID for badges at work at a distance of about 1 meter or 3 feet if we prefer.

Point being to know exactly what you want before hand and not adding it would be nice to have later.

Ron

#### MrSalts

Joined Apr 2, 2020
2,767
Beam break with a human can be more difficult than first glance - below shoulder height and you have trouble with hands, arms, legs and torso causing a double-count. Mounting high enough for most runners means it might be too high for some runners (depending if children are involved). adding a one-shot with a few-second on-time will prevent double hits.

Sunlight and sensor AGC causing saturation and causing a no-count situation. Use properly filtered sensors and orient away from sun with light shrouds.

rfid shoe tags with readers on a rail on either side of the defined track (easily keeping runner within 50cm of tag). Each runner with their own tag allows monitoring how many laps each runner completes.

#### MisterBill2

Joined Jan 23, 2018
17,870
I never said we needed an exact duplicate. How wide is a track running lane? I also mentioned a beam break. Cheap and easy a garage door safety system. RFID was just an example using EZ Pass.

We used RFID for badges at work at a distance of about 1 meter or 3 feet if we prefer.

Point being to know exactly what you want before hand and not adding it would be nice to have later.

Ron
Those garage door systems are quite interesting and not at all like a simple photoelectric sensor system.