It is not that tricky. You could also buy a soldering iron and base the microcontroller and some necessary parts completely on a perfboard. You could also add an sd-card so you can grade your students later easily.

I could provide help in designing the circuit and coding the firmware.

It actually does not matter which ÂC is used. But thats a good one as well :)

Hey, if it is just for the typing you could buy PS/2-Connector Keyboards for around $7 each. A cheap microcontroller like Atmels ATTinyXX on a custom PCB could be used to connect display and keyboard. Lets say $10 for both. Than you just need a display and a case. Depending on how many characters it should display it starts from $8 1x16 (1 line, 16 characters). Lets assume a standard case for just $1. Programming this should be fairly easy as multiple projects on the internet have libraries available. So you get your electronic typewriter for $26. It could be even cheaper. These will consume much less than 10 Watt and it would be possible to power them with rechargable batteries or big capacitors. some sources: AVR keyboard: http://avrprogrammers.com/example_avr_keyboard.php AVR display libraries are all over the web. Just my two cents. This could be an initiativ of indiegogo or something similiar!

Hey, if it is just for the typing you could buy PS/2-Connector Keyboards for around $7 each. A cheap microcontroller like Atmels ATTinyXX on a custom PCB could be used to connect display and keyboard. Lets say $10 for both. Than you just need a display and a case. Depending on how many characters it should display it starts from $8 1x16 (1 line, 16 characters). Lets assume a standard case for just $1. Programming this should be fairly easy as multiple projects on the internet have libraries available. So you get your electronic typewriter for $26. It could be even cheaper. These will consume much less than 10 Watt and it would be possible to power them with rechargable batteries or big capacitors. some sources: AVR keyboard: http://avrprogrammers.com/example_avr_keyboard.php AVR display libraries are all over the web. Just my two cents. This could be an initiativ of indiegogo or something similiar!

you dont even need arduino: http://ask.slashdot.org/comments.pl?sid=3126213&cid=41378631