IntroductionThis is a work in progress. The system has been in use for over a year it all works but I expect to get all details online soon.
Described here is a complete chip system intended for timing running races.
With minor changes it can be modified to cope with cycling or triathlons or many other race types.
Unlike other online chip timing guides, which tend to leave out a lot of the important details, this one includes everything needed, including software, to create a working chip timing system.
Software is included to operate the chip reader allowing chips to be read, processed and converted into results for importing into whatever results program you have.
In its basic version, as shown below, the results will appear as a .csv file with each line in the file giving the race number and time of the runner in that position.
The simplest version of the chip timing system is very cheap and can be built for under £1000. Most of that, about £700, is for the chip reader itself.
Optionally, you can add a camera as a backup.
What's described is the system designed for the North East Harrier League during 2016.
The races are handicapped so runners tend to finish more bunched than in a normal race of similar distance. The peak finish rate of the largest race is around 90 runners per minute and the system copes well with that.
You can see the typical results from a single meeting here.
The system was introduced into the league as the main timing system in early 2017 to replace the usual manually recorded and timed results.
This picture shows an entire 1 antenna chip reader in use at the finish line of a cross country race.
For the cross country I set up 3 of these, one on the finish line as shown here, with a slightly larger antenna, and 2 in a short finish funnel.
Main componentsTo show how little you need to make a working chip timer, here is a view of a single antenna chip timer opened out from its case and labelled.
The only addition you need is a tripod to mount the antenna on and an optional camera as backup, which would be mounted on the same tripod. Click the image for a closer view.
This reader has 4 antenna ports so can operate up to 4 antennae, but as explained later, 1 antenna will often do a better job.
The tablet shown will run for 6 hours from its own internal battery and the Lithium battery shown will run the chip reader for 10 hours so the system can be setup before the meeting and be left unattended for the meeting duration, which is about 4 hours for this particular cross country.
OverviewMost race chip timing systems are based on EPC Class1 Gen2 compliant readers and tags. That's what will be described here.
These systems were not designed for race timing, they are intended for logistics and are installed all over the world to track goods in and out of warehouses, trucks and ships so they are well established and not too expensive.
These are UHF systems and operate at frequencies around 860-960MHz. The exact frequency range varies from country to country and you will often need to set up the reader to use the correct frequencies before timing races with it.
The RFID tags for these systems are made by the million and are very cheap. If you buy a full reel of 5000 chips, which is the basic minimum order quantity, they cost around £600 which is around £0.12 per tag so they can be treated as disposable, just as bibs are.
A very common tag used in race timing is the Smartrac Dogbone tag and, after testing a few different tags I found them to be the best so that's what is described here.
A bottom of the range, fully functional chip timing system needs just the items listed above, plus a few stakes/cones and some tape to mark out the finish area and a good, enthusiastic operator.
I will first describe the simplest hardware setup and later explain how to extend this to more complicated systems.
Ability to cut cables and attach connectors is assumed. You can buy ready made cables but DIY is a lot cheaper and is a useful skill to have when someone trips over a cable and you need to repair it in a hurry.
If bought in bulk, the chips come on reels of 5000 weighing 3kg.
Component detailsHere are the details as used for the North East Harrier League system.
A lot of these can be varied to suit your own setup.
The chip readerThis is the most expensive component in the system.
The reader used here is the Zebra (formerly Motorola) FX7500.
It is available in a number of variants depending on location and the number of antennae you want to use.
This specific one is part number FX7500-42325A50-WR
All this type of RFID chip reader operate in a frequency range of 860-960MHz and each country has its own particular frequencies within that range.
They'll all work with this project.
TheFX7500 chip reader costs about £700. Be aware that sometimes they come with a power supply and sometimes the power supply is extra.
A reader power supply can come in useful for testing, setting up and allocating chips to runners so, even if you intend using batteries for races, it might be worth having at least one power supply.
The power supplyIf you intend powering the chip reader for the mains then you'll need to get the power supply. These are 24V 3A supplies although the reader consumes under 1A.
The company your buy the chip reader from should also supply the power supply and it's sometimes included in the price of the chip reader, but not always.
The alternative is battery power and that's what's used in this project.
I settled on this one: https://hobbyking.com/en_us/multistar-high-capacity-6s-6600mah-multi-rotor-lipo-pack.html
and if you wait for the right offer you can get them for under £30 each.
You will need to get a LiPo battery charger as they need special chargers. Search for a suitable one on the same website.
This battery weighs about 850g. The equivalent capacity Lead Acid battery will weigh about 2.2kg.
Battery capacity needs to be enough to power the chip reader for the duration of your competition.
To calculate the required battery capacity, for the FX7500 used here, assume about 15Wh of battery capacity per hour of use.
The computerJust about any Windows laptop or Windows tablet PC can be used. I used the cheapest I could get.
There are 2 variants in use, a Linx 810 and a Viglen Connect NXR08001. These are both 8 inch tablets running Windows 10.
The tablets are good for this setup because they are very light and small enough to be packed in a tiny box with the reader but the reader and the software will work with just about any Windows computer. It has been run on a 7inch netbook with WinXP and a bottom of the range Win7 laptop (HP 15-r101na) was used to simultaneously run 2 readers with no problems.
In use, the chip reader software uses less than 2% of the tablet's resources and, although I haven't tried it, there is no reason 1 laptop can't be used to run as many chip readers as you can network it to.
The cablesThe USB port and Ethernet port use standard cables you should be familiar with. Just buy cables that are the right length as long ones can get caught or tangled when setting up the equipment.
Antenna cables are more complicated.
The system described here uses very short cables, of under 1 metre, so cable quality is not a problem and I can use the cheapest suitable cable available.
The caseThis is a matter of personal preference. Just choose something that matches your setup.
In early tests I just used a holdall with a laptop and zipped it up if the weather looked bad, but a solid case of just the right size is much easier to handle and transport and affords some protection to the equipment.
Then I tried the much more compact children's lunch bags from Sainsburys which were just the right size but they aren't fully waterproof and I couldn't see what was going on without opening the bag.
Finally, I settled on is the Sistema 3.5l bakery box intended for food storage.
I did need to cut a hole in for the antenna lead and that should be sealed with a rubber grommet of the correct size to keep out rain.
The antennaeThere's a lot of variety here.
The first choice is to use timing mats on the ground or not.
If you decide not to use timing mats then the second choice is overhead gantries or antennae mounted to the side of the course.
Then there is antenna polarisation to consider.
UHF radio signals have trouble passing through people so, to get a good view of all the chips in a crowd of people, you need your antenna to be below or above the course so they can't be blocked, as side antenna will likely be blocked by other runners. This is a particular problem if you want a chipped start where runners are tightly packed.
Timing mats are good but they are bulky and expensive. The cost of a 6m long timing mat, suitable for most races, is still over £2500, just for the mat. That triples the cost of your timing system as the rest of the equipment is under £1000.
Overhead gantries are an alternative to mats. They are still expensive and heavy and they take time and space to set up but they can impress race organisers and you can mount adverts and clocks on them as well as the antennae.
Described here are side antennae. These are light, quick to deploy, cheap and functional but they don't handle crowds well so they'd struggle with a chip start.
The rest of the system is identical whether you use gantries, mats or side mounted antennae. They're all basically the same antennae, just packaged or mounted differently, so the same reader will work with any of them.
Finish layoutThis is rarely discussed in connection with chip timing but it is crucial to understand how layout can affect results.
Timing mats tend to be the easiest. You lay them along the finish line, runners' feet will always pass within 50cm of an antenna so if you mount the chip on the ankle or shoe then you'll get good results.
Overhead gantries are not quite so good.
Side mounted antennae suffer the most from this. A 6m finish line with the antenna on one side of the course will see chips maybe 8-10m before the finish, introducing a timing error of well over a second for those finishing on the far side of the course.
ConnectorsIf you are using a battery to power the reader than you'll need a connector compatible with the reader.
You can either cut off the battery connector and replace it with this one or you can make up a lead to convert one to the other.
Be careful of cutting off the battery connector as some LiPo battery chargers need the connector to re-charge the battery so you can't cut it off until you know your LiPo charger doesn't need it.
For the antennae cable you will need 2 connectors, one for each end.
Timing accuracyDon't expect perfect timing from a chip timer!
The main advantage of a chip timing system is that it removes the huge effort of manually recording race positions and times and typing them into a computer, along with all the usual errors and mistakes which take ages to fix afterwards.
A chip timer will do approximately as good a job at timing as a good manual timekeeper. This applies to all this type of chip timer, not just this one.
There are many causes for this lack of accuracy.
Typically, for the FX7500 chip reader, each antenna switches about every 120ms, so with 4 antennae, each antenna will be on for 120ms and off for 360ms before switching on again.
Then there's the distance from the antenna of the chip being read.
A timing mat with ankle mounted chips will do a better job as the chips will always pass within 50cm of the antenna but that's still an error of more than 0.1s on top of the antenna multiplexing delay of 0.4s and there's also the timing error depending on which foot the runner crosses the line with first, the chipped foot or the non-chipped foot.
There are ways to mitigate some of these problems which will be described later, but you'll never eliminate them altogether.
Build a systemThat's enough pre-amble. Let's build a chip timing system.
For the initial test system you will need a chip reader, an antenna, a lead to connect the antenna with appropriate connectors on each end, a Windows computer, a power supply and some chips to test.
At this stage, you don't need tripod, case, or a purpose bought computer.
Here is the material I bought but you can buy whatever quantities you like from anywhere you choose. This is just for reference:
My original chip readers were Zebra FX7500-42325A50-WR
Any laptop or desktop computer will do for testing so you don't need to buy one new just yet.
The antennae I use are these:
You may also wish to look at these panel antennae, depending on your intended setup, but they are more expensive.
Strain relief 2 per antenna cable advised (not compulsory).
Many places supply ready made cables such as this 3m cable but I advise you to get used to making up your own so you can make them the exact length needed and make repairs while you're out on a job.
You may wish to include some matching female connectors for the antenna in case the antenna comes with the wrong connector and a short lead and it needs to be replaced.
You'll also need a standard network cable, which you probably already have. A USB printer cable can often also be used instead of the network cable as the chip reader can be used via USB as well as ethernet.
Ideally, you will have bought a mains power supply with your chip reader and that will be used for testing, but, if you are planning on using batteries, you'll need a battery and connector.
Finally, if you are using a battery to power the reader, rather than a power supply, then you'll need a plug to fit the reader.
SoftwareHere is the chip reader software.
This does the configuring of the chip reader and returns files containing the chips seen.
You can process these files yourself to look up which runner has which chip.
The chips I use are preprogrammed so the first thing I do is look up the EPC returned from the chip in a look-up table and look up the runner bib number in the table.
I intend to get a very basic results program posted here soon but for those of you who can program you can use your own code for the results.
Other chip timing systemsThere are lots of other timing systems available. Feel free to investigate them, they may suit your needs better than this one. Here are some examples:
race|result. These are common in Europe and maybe elsewhere. They sell a quick to deploy timing mat. Unfortunately, it still costs £2700 just for a 6m long mat.
The company also appear to tie users into their systems, buying their chips and using their website for entries and results. I'm not sure if this is compulsory or not but when I tried to use one with my own chips I gave up because of the hassle.
Agee Race Timing. This one will sell you the hardware or let you buy and set up your own and then sell you the software. As far as I know this software is entirely compatible with the equipment described here.
ipico. Another well known system.
You'll find many more businesses that have bought the above systems, and others, and then hire out their services to individual races so if you can't justify the expense of making your own chip timing system, there are plenty of alternatives you can hire for your race.