You seem to have placed the sensor correctly in the shoe. Be sure that the Nike symbol faces the back of your shoe correctly. Also, if your receiver is not entirely inserted into the socket of the iPod, it may not pick up correctly. If, for example, you have a case in which your iPod is carried, be sure that it does not block the insertion of the receiver at all. Try taking your iPod out of the case, place the receiver back into the iPod and see if it picks up now. If it does, your carrying case would seem to be the problem. Lastly, try doing a soft reset of your iPod to see if that makes any difference. You do this by holding down Menu and the Center button simultaneously for about 6-10 seconds until the Apple symbol appears, then release both. I usually take my headphones and the receiver out when I do this. Now reinsert your first your headphones, then your receiver. If none of these maneuvers help, it would appear that you have a defective unit. Return it to Nike for a new one. It may be that your Nike+iPod unit was sitting around in the store for too long and the battery simply ran down. Good luck!