Arduino Lilypad USB with Infrared Sensor

Hi, I'm having issues interfacing my Arduino Lilypad USB with an infrared sensor (https://www.sparkfun.com/products/8958). The sensor works perfectly on a Leonardo, but when I wire it to my Lilypad USB (using alligator clips, as I wanted to test out everything before sewing), the analog input readings do not seem accurate. When I place something very close to the sensor's lens, the analog reading is supposed to increase above 200, which happens as planned when I test the sensor on the Leonardo. However, on the Lilypad, the sensor reading is constantly low, oscillating around 20. If someone could help me out with this issue, that would be great. Thanks, Anoop Bhat