Cooking grains other than rice in rice cooker?

I'd stick to the same ratio, maybe a tad less, but never more. (the rice cooker in principle is simply a heating element with its own fitted container. Since the cooking pot is covered, the evaporation may be less, hence reduce the amount of water!)

In my cheapo rice cooker, quinoa 2:1, steel-cut oats 3:1 (water:grain).

Thanks, everyone - what ratio should I use? Same as if I was cooking in a regular pot?

It works wonderfully!
I have used my rice cooker for barley, couscous, quinoa, steelcut oats, cracked wheat etc. just adjust your grain liquid ratio accordingly.

I've used mine for steel-cut oats, with good results. Supposedly much is possible -- waiting for more!

It should work for barley & quinoa which are much softer 'grains. add a tablespoon of olive oil to the water to ensure that the grains do not stick together.

it depends on what you want to make.. Yes I've made use of the rice cooker in making a lentil &rice porridge, Not tried it for other harder grains like cracked wheat.