What to say? It is only unpractical calculator, every phone have calculator, it is absolute useless machine .... but maybe nice :)
Features: - operations +-*/ - CR2032 - Arduino firmware - Talking ... but with poor volume - Auto power off - Long press on/off button to switch (silence / male voice / silence / female voice ...)
Board is designed form reverse engendering code from http://www.spikenzielabs.com/calc Also almost code is for this calculator, I just try enhance to 8digits and talking, maybe all work good.
Hola, ¿el