Current will split through the parallel part involving r3, r4 &r5. once you work out the voltage drop across it you can find the current through r3 and the remaining current will go through r4 &r5 and then you can work out the power used in r5
Pretty much what some of the other guys said, it can be a tricky bone to heal because of the blood vessel in it.
It took me seven months for mine to heal and be able to ride after they put a screw in it after having 2 casts, but once the screw was in it was a quick process.
If you riding downhill pretty sure the track is closed for public use.
You can get a fine if your caught on the track.
plus if you get hurt its a long way out/in depending how far down you are.
you could ring and ask them to see if it open
im unsure what the xc is like though
I made mine diferently to the wiki
I didn't solder inside the unit (only outside)
I conneted small wire to the start/stop spring and the lap/reset spring under the PCB.
this is because they are joined together on the PCB and I also couldn't solder onto the tab that moves across.