The bin_hex kit is useful for teaching binary, decimal and hexadecimal number systems. It has the advantage of being a hands-on tool that helps add some energy to the teaching of an otherwise difficult and boring subject (not to me!).
The bin_hex board has an 8-bit counter that is displayed in binary (8 LEDS) and in either decimal or hexadecimal. There is an auto mode, where the counter increments in 1 second intervals. In the manual mode, the count is advanced by pressing the INCR button. The count can be reset to 0 by pressing the reset button. There is also a DEC/HEX switch that selects the base of the count value displayed in the 3 digit display. This selection will allow a quick conversion of the current count value between decimal and hexadecimal.
When teaching the class, I hand one board to each scout. They press the appropriate buttons to advance the counter to a given number, and then read out the count in binary, decimal and hexadecimal. This has proven to be a popular item, though it may partially be because it wakes them up during a difficult part of the class.
The board may be powerd by a 5V walwart supply, or by 3 AA batteries (battery holder is included with the kit). Battery power is more useful, as there are no walwarts and wires to contend with.