I interviewed another school that used a hand bell for class change etc. They would get a student to walk around the school swingging the hand bell for about a minute to make sure everyone hears it, about 13 times a day. You know what, they told me the student doesn’t always turn up, then they have to rush around ringing the hand bell themselves. This is a common story I hear, where the Bell Monitor Student eventually gets the sack because they are not reliable, and the staff take back the job because it’s easier than looking after the kid. Then it become a chore, and they look to automate the bell.