class Teclado:
def __init__(self, master=None):

#data entry
    self.entry_var=StringVar()
    self.entry_text = Entry(self.frame_master, textvariable=self.entry_var, widt=10)
    self.entry_text.config(relief=RIDGE)
    self.entry_text.pack()

def act_acp(self):
    self.miCon = sqlite3.connect("base")
    self.miCur = self.miCon.cursor()
    while value(self.entry_var)!=9:
        self.entry_var= input("what up?")
        if (len(self.entry_var)!=9):
            print("tienes que introducir 9 caracteres")
        else:
            self.miCur.execute("INSERT INTO REGISTRO2 VALUES(NULL,  '" +
     self.entry_var.get()+"')")
    self.miCon.commit()

if len(self.entry_var.get()) != 9:

import tkinter as tk
from tkinter import messagebox



class Teclado(tk.Frame):

    def __init__(self, master, *args, **kwargs):
        super().__init__(master, *args, **kwargs)
        self.entry_var = tk.StringVar()
        vcmd = (self.register(self.on_validate), '%P')
        self.entry_text = tk.Entry(self,
                                   validate="key",
                                   validatecommand=vcmd,
                                   textvariable=self.entry_var,
                                   widt=10
                                   )
        self.entry_text.bind('<Return>', self.on_enter)
        self.entry_text.config(relief=tk.RIDGE)
        self.entry_text.pack()

    def on_validate(self, P):
        if len(P) > 9:
            self.bell()
            return False
        return True

    def on_enter(self, event):
        text = self.entry_var.get()
        if len(text) < 9:
            self.bell()
            messagebox.showinfo("Error", "Debe ingresar nueve caracteres")
        else:
            print(text)
            # self.miCur.execute("INSERT INTO REGISTRO2 VALUES(NULL,  %s)", text)
            # self.miCon.commit()


if __name__ == "__main__":
    root = tk.Tk()
    Teclado(root).pack(fill="both", expand=True)
    root.geometry("200x50+0+0")
    root.mainloop()

self.miCur.execute("INSERT INTO REGISTRO2 VALUES(NULL,  %s)", (self.entry_var.get(), ))