If you’re the kind of hands-on race director who doesn’t shy away from a challenge, you may have considered building your own RFID race timing system.
Building a race timing system from off-the-shelf components is a lot easier than you think. And it can give you great control over your timing costs as well as provide a stepping stone into race timing.
In the rest of this article you’ll find everything you need to start your race timing career, from understanding your options and choosing the right tools for the job to thinking through common race timing challenges and sorting out your backup procedures.
Starting at ground level…
How does RFID work?
RFID (short for Radio-Frequency IDentification) uses radio technology to identify and track objects through the use of radio tags.
The basics of an RFID tracking system go something like this:
- Pick an object you want to track (e.g. a runner)
- Take an RFID tag and program on it information about the object you want to track (e.g. the runner’s bib number)
- Attach the tag to the object you want to track
- Use an RFID reader to scan the tag and read back the information you have programmed on it
RFID technology was originally developed for industrial applications, where it was used to provide easy tracking of objects as they moved through warehouses and manufacturing plants. It was during the 90s that RFID was first adapted for use in mass-participation sports.
The very first RFID race timing systems were like any other new technology: very expensive and – let’s face it – quite rubbish. But progress has been swift and RFID has come a very very long way.
Today RFID timing is considered the golden standard for race timing and can be relied on to provide near-100% accurate results for even the largest races. And it has become affordable enough to bring it within reach of most every race out there.
The different types of RFID
There are many different types of RFID frequencies and technologies in use commercially, and not all are suitable for race timing.
Low Frequency (LF)
Low frequency RFID uses frequencies in the 125-134kHz range to identify tags in close proximity (usually less than 10 centimetres) to the tag reader. LF RFID can only handle low read rates, making it unsuitable for most race timing setups. It’s widely used in industrial applications and pet IDs, where scanning rates are low and objects are scanned through contact or with the use of handheld RFID readers.
High Frequency (HF)
High frequency RFID uses frequencies in the MHz range. HF has a longer range that its LF counterpart (typically up to a meter or so), can handle a higher read rate and be used to transmit larger data payloads. However, this is still not enough for most race timing applications.
Ultra-High Frequency (UHF)
Ultra-high frequencies are the most widely adopted in race chip timing systems. UHF RFID systems use frequencies in the 860-960 MHz range and can be used to detect as many as 1,000+ tags per second as far as 10-15 meters from the reader, making them ideal for wide and busy finish lines where several tagged participants may be crossing in a short space of time.
NFC vs RFID
Although technically a subset of RFID, NFC technology (short for Near Field Communication) deserves special mention amongst RFID technologies.
NFC sits in the LF/HF part of the RFID spectrum and has been increasingly adopted for timing and runner identification in trail and ultra races. Part of the reason why is the low cost of wearable NFC tags (these tags use similar NFC chips to the one you’ll find in your contactless credit card), but also the in-built NFC functionality available in Android smartphones, which essentially can turn any Android phone into a NFC tag reader.
Essential components of an RFID race timing system
Building your own RFID race timing system may seem daunting, but there really are only a few core pieces of equipment you’ll ever need.
You can build a system capable of timing even the largest of races with just a few thousand dollars – or less, if you shop around for second-hand components. Here’s what you will need:
RFID tags are worn or carried by participants and are used to identify each one uniquely at timing points. Tags are made up of two components: 1) an RFID chip which is programmed with information about the carrier of the tag, e.g. their bib number, 2) an antenna which enables the connection with the RFID reader.
RFID tags, like the super popular Smartrac DogBone, can be attached on participants’ bibs, worn on the shoe or, for bulkier active tags, strapped around the ankle. All of these can be equally effective, but some make better choices than others depending on the type of event you are timing and the antenna setup you plan to use. We’ll take a closer look at the different choices for RFID tags later in the article.
RFID tag readers
The tag reader is the “brain” of the chip timing system – and the most expensive item on your shopping list. It uses radio antennas to detect RFID tags, decode the information stored on them (processing and combining multiple readings where necessary) and transmit that information to the race timing software.
RFID readers can be handheld, mountable or desktop and vary significantly in cost depending on the number of antennas they can accommodate (usually 2, 4 or 8), their read rate, connectivity options (ethernet, Bluetooth, Wi-Fi) and other specifications.
Both the Impinj R420 and Zebra FX9600 (formerly Motorola) are very popular choices of race timing readers in the $1,000 – $2,000 range. They both have 4 antenna ports and with the right antenna setup will give you all the power you need to time any race, however large.
The job of antennas in an RFID timing system is to detect RFID tags and transmit data from the tags to the tag reader. Most antennas are passive, that is, they not only connect to the RFID reader but are also powered by it.
There are three types of RFID antennas commonly used in race timing systems:
Ground antennas have been used in race timing systems since forever and are the antenna of choice for major marathons and very large events.
Ground antennas are placed across the finish, start or intermediate timing line. The mat or plastic cover shields the antenna coils underneath which create an upwards radio field facing incoming tags.
Ground antennas work great with both shoe tags and bib tags and are usually foldable and can be extended to any width by connecting multiple antennas together.
Side antennas are upright antennas usually positioned in pairs facing each other at either side of the timing line. They create a fairly narrow wedge-shaped field and are oriented slightly outwards facing incoming tags just as they cross the timing line.
Side antennas, particularly the square variety like the hardy MTI outdoor antenna, are by far the most versatile type of RFID antenna. They can be used in all types of events and are the top choice for high-speed events, like sportives and road cycling events, where even the lowest-profile ground antennas can be dangerous to participants.
Overhead or aerial antennas can be used in conjunction with side antennas on the top of finish-line gantries to add a radio “curtain” to the side antennas’ radio “wall”. They’re typically used to beef up read rates in high-speed races, like road cycling and motorsport events.
Race timing software
Making sense of RFID data captured by the reader and translating that into neat race times is the job of specialized race timing software.
The important thing to keep in mind when buying timing software is that not all software will work with every RFID reader out there. Most software will work either with a dedicated hardware setup or a select list of readers, usually from the bigger manufacturers like Impinj, Zebra, Alien etc.
If you feel adventurous and would consider developing your own race timing software, make sure to check whether the manufacturer of the RFID reader of your choice offers a software development kit (SDK) to help streamline the process.
Most RFID antennas on the market come without any mounting kits, which is something you’d need to buy separately to set up your antennas the way and in the direction you want them.
Tripods are particularly good for that job and you you can buy fairly inexpensive professional tripods from Amazon. Then on top of that, you may or may not need to buy a mounting kit to securely attach the antenna to the tripod. Something like this, which works really well with the MTI antennas we discussed earlier:
If $30-$40 for one of these is too much (you’ll need one of these for each of your antennas), then you can look at cheaper fixed mounting brackets from pretty much any hardware store.
Last but not least in your RFID timing system build, you’ll need cables to connect your antennas to your reader (and your reader to your laptop, but those are fairly standard Ethernet cables).
The importance of picking quality cables is easy to overlook. Seeing as you’ll be likely operating outdoors and moving things around, you should consider investing in durable, insulated cables that can withstand whatever the weather may throw at you.
Getting the length of your cables rights is also important. You’d think that the longer the cable the better, but, unfortunately, there are reasons why you want to avoid overly long cables:
- They’re more difficult to transport and more prone to causing accidents at busy timing points
- UHF cables suffer from loss of signal with length, so buying longer cables means having to invest in more expensive low-loss cables
So, when it comes to cable length, give yourself a bit of slack to work with, but don’t go too long.
Popular add-ons for RFID race timing systems
While not essential, there are a few more items you could add to your DIY chip timing system to extend its functionality. Below we list some of the more popular race timing add-ons.
A results kiosk usually takes the form of a touchscreen box with a ticker tape printer on the side where participants can walk up to and look up their finish times after the race. Results kiosks are becoming very popular with racers and would be a good investment to make for any aspiring race timer.
Everybody loves a race-day photo, right? Thankfully, with RFID you don’t need a photographer standing by. You can set up a camera that can be connected to your timing software and triggered whenever a participant crosses the finish for that perfect finish line snap. Photos can be tagged and timestamped automatically, saving you the hassle of having to sort photos after the race.
LED display screens
Similar to the kiosk, LED display screens can provide a convenient way for participants and spectators to view race results as they come in. These are less interactive than results kiosks, but can cut back on lines for results, thus providing a good solution for larger races.
Types of RFID Tags
When it comes to RFID tags, and depending on your hardware setup (particularly your choice of antennas) and type of event, you will have a choice between different types of tags that vary in cost, reusability and performance. So it’s worth spending a bit more time understanding your options.
Disposable vs reusable tags
One of the more important choices you’ll need to make is whether you go with disposable or reusable tags.
There’s three things to consider there:
- Tag durability
- Logistics, particularly in collecting and re-programming reusable tags
Reusable tags can be re-programmed for repeat use, which means you will pay the – typically higher – cost of a reusable tag once and be able to use the tags again and again. In contrast, disposable tags, which are cheaper to manufacture, will be distributed to participants or be embedded in a bib never to be used again.
In terms of logistics, throwing a tag a