 # A car with Keyboard input

Hi, My project is A car with Keyboard input. You can find the circuit on http://www.instructables.com/file/FCZTM1CGKS0S6SL . I will just replace the decoder in this circuit that will convert instead of mobile signals the keyboard signals into their binary equivalent. Can you please tell me a decoder that can do this.

Thanxxx

The output of the tone MT8870 DTMF decoder is just BCD (binary coded decimal) So, in this case... PA0-PA3 on the ATmega are being used.

Binary coded decimal is this: PA3..PA0 0000 = 0 0001 = 1 0010 = 2 0011 = 3 0100 = 4 0101 = 5 0110 = 6 0111 = 7 1000 = 8 1001 = 9 1010 = A 1011 = B 1100 = C 1101 = D 1110 = E 1111 = F

Actually, BCD typically ends at 9, but the DTMF decoder can actually use all 16 combinations.

Actually, notice there are inverters between the Q outputs and the PA inputs. So in the code above, everywhere you see 1, you need to make that 0 and vice-versa. Unless you are keeping the inverter.

You haven't told us anything about your keyboard so telling you how to wire it up is impossible. But all you need to do is take your keyboard and make sure it outputs those codes.

The output of the tone MT8870 DTMF decoder is just BCD (binary coded decimal) So, in this case... PA0-PA3 on the ATmega are being used.

Binary coded decimal is this: PA3..PA0 0000 = 0 0001 = 1 0010 = 2 0011 = 3 0100 = 4 0101 = 5 0110 = 6 0111 = 7 1000 = 8 1001 = 9 1010 = A 1011 = B 1100 = C 1101 = D 1110 = E 1111 = F

Actually, BCD typically ends at 9, but the DTMF decoder can actually use all 16 combinations.

Actually, notice there are inverters between the Q outputs and the PA inputs. So in the code above, everywhere you see 1, you need to make that 0 and vice-versa. Unless you are keeping the inverter.

You haven't told us anything about your keyboard so telling you how to wire it up is impossible. But all you need to do is take your keyboard and make sure it outputs those codes.

Sir, If I use a matrix keypad with it instead of mobile then this circuit and the programme that is given in next step will work.

Are you asking me a question or are you stating that you have figured it out?