Hello everyone. I'm new to using Arduinos (and pretty much any electrical componentry). I're read up on the arduino system and think it would be ideal for an idea I have. I'm not new to building things, and am pretty competent with assembly and fabrication, so that part isn't where I need help. What I need help with are the electronics in the system.
I'm looking to make a portable timing system to be used on track bicycles. It would be in use when riders don' have access to a facilities timing systems, or someone to work a stopwatch. The basic idea is to make a stopwatch that uses a photo-emitter/sensor and is tripped when going over a reflective strip.
I'm looking for a system that can be used like this.
rider lays strips on track at appropriate intervals, with a start, and stop strip.
-once rider is on the tack and ready to use the system, he would "wake" it up wit a switch on the handlebar.
when rider travels over the first switch, the watch starts.
-when rider travels over the second strip, the watch stops.
-rider then trips handlebar switch to put system to sleep, or mark it as a lap.
-subsequent passes run over the strips are recorded as laps as well.
-data to be logged to be reviewed and recorded after the training session.
I'm looking to make a housing where the unit can be mounted on the bike, withing the front triangle, hanging from the top tube of the bicycle. A bracket with the emmiter and sensor would be mounted on the left fork leg and attached to the housing via cable. A battery pack would be contained withing the housing. A wake up/lap switch would be mounted on the handlebar and a cable run to the main computer housing.
I'm not all that familiar with what is out there and available when it comes to electronic components and haven't build anything like this before. I can make great solder connections as I have repaired the physical components of electrical systems before and I also build/craft/fabricate things on a regular basis. I know it won't be easy, but then again nothing worth building is. Can you guys offer me some guidance? Thanks, taras.
Sensing those strips reliably will be the tricky part of the project. You will have to spend some time trying out different sensors and positions.
Any ordinary Arduino like Uno should be ok for your project. To minimise size I would consider a Nano 3 or Pro Micro. It can be powered with 3 or 4 x AA rechargeable cells via the 5V connector, bypassing the built-in voltage regulator that the barrel connector feeds. Don't use 4 non-rechargeable cells, too much voltage, 3 would be ok.
They use a similar timing system with go-kart racing.
One unit resides with each machine, an IR trip is mounted alongside the track.
As each machine passes, it triggers several arrangements within each machines units.
I'd look up how they work and get some idea there.
I like the idea of the card reader. Would I also need other componentry like a breadboard to base all of this off of?
I know spoonfeeding a newb isn't what these forums are for, but what else would I need? Most of my experience is building boats and the like, so I'm a little out of my element with this stuff. Any good resources for me to look up so I can learn and maybe ask some more educated questions?
Yes, a breadboard will be invaluable for getting your circuit working. However, breadboards are fine for use on the bench but if strapped to a bicycle, you will have components falling out at random! You will either have to put up with this, or solder up your components onto stripboard or tripad board before testing on the track.
A few sundry components will be useful for prototyping. Some LEDs and series resistors (220 or 330 ohm), some 10K resistors, some pushbuttons and toggle switches and some solid core hookup wire in several colours (red black green yellow...).
Basic tools: wire cutters & strippers, fine-nosed mini pliers, a cheap digital multimeter.
Bluejets, I had looked into that, and although it seems good on the surface, the problem here is that some testing intervals will begin within the bank of the velodrome. The IR sensors are fine when used in a perfectly horizontal plane, but that won't be possible with a velodrome set up.
Paul, thanks for the tips. I didn't realize that breadboards would provide such an insecure connection. Soldering it is.
Not that they only travel in perfectly horizontal lines, but are only useful when used in a fixed plane. The way that the IR beams are set up on kart tracks is on a fixed location, pointed horizontally across the track, and the karts are crossing the beam in a fixed plane. The nature of being able to move the timing strips to different points of the velodrome means that the beam would have to be calibrated for each location on the track and the lean of the bicycle (which karts don't do) would make it impossible to set up the IR system as on a cart track. If it can all be self contained to the bicycle, as I would like, and be able to utilize the reflective strips, then this seems the way to go.