DTMF is the acronym for Dual tone modulation frequency. Robotic vehicle based on DTMF technology is explained in this article. Here is a circuit that operates the robot without using a microcontroller. This circuit consists of simple ICs.
When a key is pressed from our mobile, it generates a tone combination of two frequencies from our keypad. In the two frequencies, one is high frequency and another one is low frequency. This frequency can be decoded by the decoder IC into binary sequence.
DTMF Based Robotic Vehicle Circuit Principle:
DTMF based robotic vehicle circuit consists of DTMF decoder IC, driver IC l293D IC and motors.
DTMF decoder IC used is HT9107B. It has 18 pins. Tone from DTMF encoder is given to the DTMF decoder IC. The decoder IC internally, consists of operational amplifier whose output is given to pre filters to separate low and high frequencies. Then it is passed to code detector circuit and it decodes the incoming tone into 4bits of binary data. This data at the output is directly given to the driver IC to drive the two motors. These motors rotate according to the decoded output.
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