We have developed a new product called Sajda Recorder, an electronic device that displays on its screen the number of prayer cycles and prostrations performed to help those who get confused or forget during prayers. Is it permissible to use it?

Yes, it is permissible to use this electronic device. The early generations of Muslims used a precedent to such a device. It was mentioned in Ibn Sa’ad’s al-Tabaqat and in al-Baladhuri’s Ansab al-Ashraf that Mohammed Ibn Sirin said, “’Umar Ibn al-Khattab (may God be pleased with him) experienced forgetfulness during prayers, so he asked someone to stand behind him during prayer to remind him in case he forgets.”
Miswar Ibn Yazid al-Asddi (may God be pleased with him) narrated, “I witnessed the Messenger of God (peace and blessings be upon him) forget to recite some verses during prayer. After he ended the prayer, a man told him, ‘O Messenger of God! You forgot such-and-such verses while reciting. The Messenger replied, “You should have alerted me.”
Anas Ibn Malik (may God be pleased with him) narrated that the Companions of the Messenger of God (peace and blessings be upon him) used to remind one another during prayers. He also reported that when he would start to pray, he would have someone behind to remind him if case he omitted any verses during recitation.
In his book Al-Mughni, Ibn Qudamada wrote, “Amir Ibn Rabi’ah said, ‘I was in Mecca while a man was praying before the maqam; there was someone behind prompting him and it turned out to be ‘Uthman Ibn Affan (may God be pleased with him).”

The ruling
Based on the above-mentioned proofs, it is permissible to use this electronic device as long as it helps the person offering prayer to concentrate and does not cause any sort of distraction.

And God Almighty knows best.