I need to connect two photo cells/reflectors together. One pair set at 1.5 feet off the ground and the other pair set at about 4 feet off the ground at the finish line of a hill climb event to make sure I get a timing pulse if the bike is in the air as it crosses the line ,so at least one pair will read the bike as it crosses , can this be done and if so how would I wire it , I'm new to this type of timing and I could not find any other discussions on how to do this,,Thanks,
Kirk

In your situation Alge photocells schould be conected paralell, because they have normally open working contacts(in real: open collector NPN transistor). So link between coloured banana(red)contacts of cells, link between black contacts, and connect one line to chronometer -coloured to coloured, black to black. Now, no metter if one cell or both of them send impulse -you got impuls on chrono.
Your proposition will work as need to cross both cells simultanously to get impulse!

Jaroslaw Grondal, Poland
www.gro-timing.com

Thank you very much
Kirk