Light aircraft pilot reported an NMAC with another light aircraft in the vicinity of 2R2 airport.

Narrative

On a VFR flight from EYE to ZZZ I departed heading southwest under the IND airspace (2;100 ft. MSL) to go west and south around the IND airspace and to avoid the JPG A MOA on the south east side of IND. I approached 2R2 at 2;000 ft. MSL I was planning to turn south before getting to close to the airport traffic pattern. I was aware of my altitude relative to the airport pattern altitude; I was not on frequency nor did not see any aircraft in the vicinity - I was looking both visually and at ADS-B traffic on a tablet. When I turned southbound; I saw Aircraft X in the traffic pattern under me - I do not know the distance but it was closer than I would like but it was not close enough to take evasive action (guessed distances above in conflicts). Once I was out of the airport area I check my ADS-B to see why I was unable to see the traffic; I found that it was not connected to the antenna therefore I was only able to see traffic visually. In hindsight; I realized that I should have (1) stayed north of and extended beyond the airport to the west before turning south; there was no need to cut between the airport and controlled airspace; (2) be on frequency with 2R2 since I was near potential traffic; (3) double check my connection with ADS-B prior to departure. I will change my flight path and or use flight following on my next trip to EYE.