I cut the cord off of an old broken keyboard. This allows students to practice typing without you having to sacrifice computer time for other students. Student use the keyboard to type their weekly vocabulary words or word study list. Make sure you include a chart to show which fingers are used to type the correct keys. For a challenge, students can type the words with their eyes closed.
This center is a good way to allow low level students to practice spelling without an actual written work product. It is a "safe" activity for them because no one can see their mistakes or their low level words. The kinesthetic action of typing is also a good way to meet the needs of students with behavioral issues because it forces them to focus and the repetitive action can actually be calming.