The Open Design Orienteering Timing System

Uni finished, the next step not yet begun - obviously time for a large project. I have been kicking around the idea of building a custom timing system for orienteering for a number of years, but I finally got around to setting aside some time and (possibly just as importantly) asking the Orienteering Foundation for funds to go off and buy development and evaluation hardware.

What is the aim of this project? To build a proof of concept low cost open design electronic timing system for  use in orienteering training and small events. For those unfamiliar with the sport an Orienteering race is effectively a cross country race with no streamers showing you where to go - so you have to use a map instead. Thus it becomes a challenge of navigating between checkpoints as fast a possible. 

An example course and map, around the southern side of the University of Bristol campus

Validation systems to ensure competitors actually visit all checkpoints or controls are essential in any races with any sort of stakes. While this used to be achieved with pin punches and bits of card, modern orienteering will use high performance electronic timing systems wherever possible. To newcomers this can often be a very good advertisement of our capabilities ad worthiness as a sport. Unfortunately the current solutions for electronic timing are incredibly expensive which poses issues for clubs starting up or clubs looking to deploy their timing systems in areas prone to theft. Therefore I have the grand plan of building the design (and software) for a low cost electronic timing system. The low cost will reduce the barriers that new clubs can face, while keeping the design open and accessible will allow contributions from other members of the orienteering community to change the capabilities of the system to their requirements.

The final goals are:

• Have 100 competitors on a 20 checkpoint course for under £500.
• Ensure top level designs and software are straightforward and accessible.
• From a performance standpoint checkpoint registrations should ideally take <20ms at a range of under 0.5m, while competitors should have the ability to record as many checkpoints as possible. Orienteers, being used to current timing systems, will also require the checkpoint registration times to also be recorded to around centi-second accuracy over a course that could take 24 hours!
• From a safety standpoint it would also be helpful if checkpoints remember who has visited them as this can help with search and rescue (if needed).
• From an operational standpoint the entire system should still work if it has been submerged for a while in a nice wet bog.

To hit these goals 13MHz RFID communications work quite well, allowing competitors to carry around a couple of kilobytes of read/write memory in fairly weather proof packages while also allowing fast communication times on protocols that are likely to last for another decade or so (at least). So far I have been working with the CR95HF chip from ST Micro, which is multi-protocol and also has some ST written drivers for using it to talk to NFC cards which is pretty useful. I expect that eventually I will have to specify more stringent RFID tag requirements for compatibility (as in possibly a specific set of MIFARE standards) as supporting a wide range of tags looks to be beyond the abilities of the micro-controller being used. It also requires minimal external components for RF drivers which will be useful when I finally start thinking about PCBs.

Using an Arduino compatible chip is also good, as writing the top level code in the Arduino style will allow it to be read by beginners. Work over the past month trying to get the RFID drivers to compile onto the AtMega328 have shown me that the lower level 'under the hood' programming will be less friendly (just so that it can fit).

At some point I will also have to start thinking about timing tolerances and potentially Real Time Clocks, but for the moment all effort is being put towards getting the RFID systems to talk!

The most important part, a logo/icon for the ODOTS

An alternative name - and logo, I think I must have had the render settings set much lower for this one!

It is important to note that I enjoy using the current timing solutions a lot, which have been honed over a number of decades to provide reliable, painless timing with brilliant precision. Recent moves to contactless registrations have made passing through checkpoints very fluid and don't require any slowing down at all (brilliant if you are trying to live up to your internal image of running along like the the three hunters).