Any 10 pin remote release should work, Nikon has a rather expensive IR one the ML-3 (note the ML-L3 from your D5100). There are also a number or RF releases available for much lower prices on eBay. B&H also sells RF releases at intermediate prices. There is a ProMaster RF release available at many local camera stores.
The receivers for most, maybe all, of these devices have a foot that mounts in the hot shoe. Mounting the receiver in the hot shoe is just a convenience. There are no electrical connections in the receiver foot and the receivers are light enough to safely hang from the cord to the 10 pin socket, I frequently use my ProMaster RF release hanging from it's cord.
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