3000 budget, can only afford to buy second-hand equipment, this generation of glasses seems to be unstable quality?

Don't know how other AR glasses, how development platform of the manual, AR developers can suggestion?

Development goal is AR version of the speech recognition to eliminate subtitles, USES gestures conversion algorithms identify English letters (a total of 26 gestures), access to the pinyin input method users choose some words, finally the text to speech output

Taobao looked MAD Gaze plus configuration parameters, as well as some evaluation, it seems to be the best choice of the budget?

Seek better advice