Hi all,
Long story short I've just gotten involved with a Pedal Prix club at work and had a race today.
What we'd like to do is be able to display real time data in the pit, data like position on the track to start with and maybe add other things on down the track.
There are ready made solutions out there with are upwards of $250 per unit... Bit beyond the current budget.
My current line of thinking is why not try with arduinos and xbees (or alternatives) and transmit gps data back to a central location, in this case the pit.
I'd like to not use GPRS as it's proven unreliable each race and another cost to incur each race.
I know xbees would have the range to be able to do this. Reliability of the signal I'm not sure about at the moment, any real life experiences and stories would be appreciated.
So some questions.
Has anyone attempted something like this before? If so how did they go about it?
Would the pit computer just poll each xbee individually? How quickly can this realistically be done?
Can the data collected then be overlaid onto google maps and a start/finish line be set using gps coordinates? Some information I found suggested RFID tags with IR sensors etc which wouldn't work as we can't set up extra equipment at the start/finish line.
Any ideas and help would be appreciated.
Cheers,
Dave
Hi,
Interesting project, of curse I got some questions:
How big is the track? Is like a cart (open flat aria)? or a track like F1 (long/hils aria)?
Do you really need to get GPS data or just lab/position data of each car on the track?
How accurate you need to be the data like 1 to 1 real time speed/loc of the car or just parts of the track?
I made that questions because i got many ideas how you can make that kind of system and cheap.
Load gps-tracking-apps into driver's Iphone/Android Phone (3G/4G).
http://blog.dreamcss.com/android/best-android-gps-tracking-apps/
GPRS:2.5 generation
3G:third generation
4G:fourth generation
Domino60:
Hi,
Interesting project, of curse I got some questions:
How big is the track? Is like a cart (open flat aria)? or a track like F1 (long/hils aria)?
They would be short cart tracks, the track length is 1.4km, almost a mile.
Domino60:
Do you really need to get GPS data or just lab/position data of each car on the track?
How accurate you need to be the data like 1 to 1 real time speed/loc of the car or just parts of the track?
There are probably about 100+ bikes on track at any given moment, I'm only interested in tracking 3, having where they are at each part of the track would be beneficial. If something happens to them and they stop, when they are coming up to pit lane, record lap times etc.
We've got a system at the moment that is meant to show where each bike is on the track, much like in a F1 race where the car is on the actual track. However, it doesn't work and when is does its very intermittent and costs about $60 in phone usage each time to get it going. The developer of the system is more than a bit clueless as to how to fix it.
What ideas do you have?
sonnyyu I really don't want to use a phone, even if it is easier as it costs money each time and the riders are school aged people.
As you described the only way I'm thinking is to use RX,TX antennas, as a base you will have the receiver antenna and the bike will have the transmitter antenna for that you can use nRF24L01 and transcivers and program them with arduino, of curse you will need GPS too because in this way you described there is no other way to know where they are exactly so look how I'm thinking:
As a base station you will have a PC/Laptop with the Receiver Antenna module and the bikes gonna have the transmitters also a GPS module which gonna transmit to base the actual location of the bike, the GPS data will not be 100% accurate like 1~3 meters error but you will know where exactly is the bikes.
In the other way on Base you will receive the data and thru a (homemade program) you will see real time on (google) map where the bikes are + from the program or visually you will be able to record his lap.
But for the lap i would recommend other system because the GPS will not give accurate time lap.
Thanks Domino60,
The lap times are really for our own benefit and tracking of how students are going, in the end it would be more accurate than our current system, which doesn't work 95% of the time and no one can work out why, even the developers... so we've been doing it manually as they come past our tent in pit lane.
I think what you propose would work fine in our situation.
I might get a couple and have a play and let you know how it goes.
Cheers 
Nice to hear that you liked it
The base station will cost about (components):
nRf24L01
GPS
Arduino Uno
needed components (resistors..etc)
Approx: 20~30$
A single Bike will cost:
nRF24L01
mini arduino (or your own circuit ATmega328P)
GPS
needed components.
Approx: 10~15$
I forgot to tell you about the GPS :
http://www.aliexpress.com/item/Wholesale-High-Quality-3V-5V-GY-NEO6MV2-Flight-Controller-GPS-Module-with-Flight-Control-EEPROM-MWC/32307809963.html
Here is a link of a cheap GPS and working really well, I personally tested it.
The only what's left is to program them all, that's not really hard of curse the kinda tricky part is to create your own program which gonna take the GPS data from arduino and put them on a google map and saw you life tracking bike.
So in this way you have your own Base tracking system without paying anything anymore 
That's for 1.2Km max range if you will need better range you will need to update your base nRF24L01 antenna with a better antenna, ow and something last, put your base antenna on a long high post to get clear data.
Thanks heaps. The whole system is going to be what we'd like it to be.
I was looking around at the nRF24L01's, which one would be best considering it'll be mounted inside the bike, imagine a three wheeled trike that is enclosed with plastic / fibreglass? We "might" be able to mount the antenna externally to the bike if I get one of those units.
If you gonna mount them in the bike get that kind of antennas because
they have better transmitting and receiving area/zone than the simple linear antennas.
The simple antennas need to be aligned in the same vertical position as the base antenna to get
normal and fast data but as you say you gonna put them on bike they may lose signal to transmit so
get better that kind of antennas:
2.4Ghz Circular Polarized Antenna.
They transmit 360` deg. ofc they have few angle degree dead zone above and bellow but in general they get better (cover range).
Thanks mate, ordered most of the parts aside from the antenna which I'm struggling to find a 2.4ghz version, they're all 5.4ghz which from what I can tell won't work properly.
Also all of this will be running from a battery, I've got some Pololu 5V Step-Up/Step-Down Voltage Regulators so we've got flexibility on what batteries we can use.
Do you have any suggestions for a voltage monitor to connect to the batteries directly?
I'm going to send this data back to the pit so we know when they need to be changed over.
Thanks again for all your help so far mate.
I just found them on aliexpress haha
Thanks mate, ordered most of the parts aside from the antenna which I'm struggling to find a 2.4ghz version, they're all 5.4ghz which from what I can tell won't work properly.
You just need to look in the right place
Here is a link, you can trust and order from this website, they return money back if you don't receive your items on time.
http://www.aliexpress.com/item/2-PCS-Lot-2-4G-2-4GHz-Circular-Polarized-Clover-Leaf-antenna-L-Type-Plug-for/2032961211.html
Do you have any suggestions for a voltage monitor to connect to the batteries directly?
A Digital voltmeter would be fine:
Thanks again for all your help so far mate
No problem, give me future updates I wanna know your progress
Will definitely keep you posted mate.
I think if I do a voltage divider to take a maximum of 11v and feed out 5v I should be able to relay that back to the pit
Ok, so I've put together and tested the units in a race situation.
They worked well aside from the fact the nRF20L01 modules couldn't quite get the distance, lots of trees around and through a few marquees on it's way up to the receiving station, 9.5-10m up in the air.
I've ordered two XBee Pro 63mW RPSMA - Series 2B (ZigBee Mesh) units to test to see if I can get a better range out of them.
Other than range, still need to work out how to get a map to display properly and better power supply. Thinking LiPo's now.
Overall I'm happy with the system as a proof of concept.
Oh, I ended up adding more to the units, we've now got two switches which can indicate whether someone is pitting for water, rider change or both together to signal for help.
They worked well aside from the fact the nRF20L01 modules couldn't quite get the distance, lots of trees around and through a few marquees on it's way up to the receiving station, 9.5-10m up in the air.
You mean nRF24L01, and 10m in the air what exactly? You need better antenna and yes of curse the trees and over obstacles in between are a bit of problem.
You need to put down the data rate in kbps.
Looking the Frequency of the xBee you gonna buy it's in the same frequency as the nRF24L01, 2.4Ghz
It's all depends on the data rate and antennas.
As I know to get thru obstacles you need a lower Freq. band but can't understand why the nRF is not working.
Questions:
- What is the nRF24L01 you have? is the Power Amplifier one (PA)?
- Do you used just the standard 2db antenna?
nRF24L01 should not be a problem in your case, you need to down the data rate and get better antennas.
Here is a video that I like, Range test of nRF24L01 PA SMA:
If you see his other video he used 2nd antenna.
You need to change the transmiter antenna to a coverfeath and the station antenna with a higher dbi pointed. In that way you will get more range and almost 0 signal lost.
Keep me updated
Thanks,
D60
Hey mate,
Used the standard 2dBi antenna's, I've got the cloverleaf ones to try now too, unfortunately I didn't have these on the day. I will give them a go also, unfortunately can't do the same area but can recreate a similar place.
9.5-10m's up in the air was referring to a 7m pole I had taped up a tree to raise the height of the receiving unit.
I did set the data rate to be 250kbps.
The units I ordered were the PA LNA ones, unless I was duped. Just looking at google maps it got about 400 meters whilst the bike was stationary.
One question with the cloverleaf antenna's, will they give better penetration of trees and marquees than a standard antenna of the same dBi rating?
Wondering also if mine being the unshielded version would affect it?
I know this race we were at is the biggest track and also has the most obstacles to overcome.
Cheers
