I hesitated too - but went for the safer "device". The fact is that yes, in an unambiguous situation eg you're a photographer, someone just called for emergency news and you're rushing out of your home yelling "I'm taking my camera" to your spouse, yes you will use this exact sentence, but in a general sense it has a broader meaning. Actually, I'm even surprised wordreference doesn't even reflect that usage: http://www.wordreference.com/fren/appareil
Another use besides "device/machine/apparatus" is "airplane". Not sure Duo accepts "I take my plane" here, though. :D
It is quite common to us "appareil" for telephone in French. When ask who is on the other side of the phone, we say "Qui est à l'appareil ? " The response is usually " C'est xxx à l'appareil."
Because 'I take my device' is an unusual (but not unheard of) sentence in English, I wrote 'I take my equipment' which would be easily understood, but not accepted. The word 'device' conjures up a special purpose, unusual, clever, ingenious, problem-solving piece of equipment. I agree with SeanMeaneyPL on this page.
What exactly does "device" mean here? I put instrument because that's always what appareil has seemed to mean to me - a piece of equipment that does a specific job. I guess that's a device, but that's not a word I would use in english. The only time I hear people say "device" they really mean "electronic device" like an iPad.