An unusual Device question

[Ash Williams]

Okay, so I thought of giving a character with a Device like the Ivlivs from the Heroes of Olympus series. Basically, depending on what side the coin lands, a different weapon appears. I've already figured that I'd use Weapon Summoning (with the other weapon as an Alternate Power). The question is: How could I go about doing the "randomness" of the coin toss? Any suggestions?

[Bladewind]

Depending on how many alternate weapons there are, add a quirk of "random weapon" and roll a d20 to see what gets chosen.

You'd have to have a chart of what's what on the roll ahead of time but it's pretty random...

[Ash Williams]

I've only got two weapons (a flail and a shield [not a thrower like Steve Rogers']). After discussing it with my friends, I just decided to go with a regular coin-toss to decide. Since the character is a slightly toned-down version Marvel's Hercules, this seemed the way to go.