// emit an observable every time interval
Observable<Long> intervalObservable = Observable
        .interval(1, TimeUnit.SECONDS)
        .subscribeOn(Schedulers.io())
        .takeWhile(new Predicate<Long>() { // stop the process if more than 5 seconds passes
            @Override
            public boolean test(Long aLong) throws Exception {
                return aLong <= 5;
            }
        })
        .observeOn(AndroidSchedulers.mainThread());