public void add(Device d) {
		if (d == null) {
			return;
		}

		DeviceList newlist = new DeviceList(d);
		if (this.head == null) {
			this.head = newlist;
		} else {
			DeviceList temp = this.head;
			boolean notInSet = true;

			if (this.head.device == d) {
				notInSet = false;
			}

			while (temp.next != null && notInSet) {
				if (temp.next.device == d) {
					notInSet = false;
				}
				temp = temp.next;
			}

			if (notInSet) {
				temp.next = newlist;

			}
		}
	}