Room A: 32 students, infrared, eight-millimetre frame
The frame sits proud of the glass. You can see it if you look and feel it when writing near the edge. The teacher did not mind; she writes in the middle.What she did mention was dust. Chalk settles on the frame, and one receiver stopped responding after a spring term of it. A dry cloth fixed it, twice.
The school buys cheap styluses. They work, because the panel does not care what touches the grid. A snapped pen is still a finger.
Room B: 26 students, capacitive, flush glass
Feels like a very large phone, which the students noticed within a day. The teacher writes faster because the ink sits under her finger instead of a few millimetres away.Then a student knocked the top corner with a metre ruler during a demonstration. Not hard. There is now a coin-sized area that no longer responds. The panel displays perfectly; it just does not feel that spot.
Repair means replacing the panel, not the frame.
The contact count that surprised us
A forty-minute class generates two to four hundred touches, counting board work, menus and volume. Over twenty weeks that is well over thirty thousand contacts, concentrated in the middle third of the glass.Both technologies survived the count. What killed them was dust in one room and one impact in the other. Neither is on a datasheet.
What the school bought next
Infrared for the general classrooms, because a frame strip is a fifteen-minute swap and the stylus policy is 'whatever is in the drawer'. Capacitive for the glass-walled training room, where the flush surface matters and the room is supervised.Same brand, same software, different failure economics. The decision had nothing to do with which one felt better to write on.
Mounting height matters more than either
Bottom edge at ninety centimetres from the floor, and a child can reach the top of the board. Put it at 110 because it looks tidier on the wall, and the back row cannot write on the upper third.We see this in more classrooms than any touch problem, and it costs nothing to fix at installation and a service visit to fix afterwards.