4 ms·

Show HN: Canny the Robot – Programming a device with headphones

16 points by akumpf 11y ago

akumpf 11y ago
Direct link to video here: https://www.youtube.com/watch?v=780A0cv1qgA https://www.youtube.com/watch?v=780A0cv1qgA Any comments or questions about how the robot/audio programming works are more than welcome :)
- hellbanner 11y ago
  Yes, is it binary.. ?
  - akumpf 11y ago
    The audio used to program the robot is analog (tones in the form of sine waves), but the data itself modulating the tone is binary. More specifically, it's AFSK. See the diagram/info on the Wikipedia page about for a more detailed explanation. https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_FSK https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_F...
sprobertson 11y ago
Could you go into more detail about how the main decoding circuit works? How does it turn an audio signal into UART?
- akumpf 11y ago
  Serial/UART is just a simple way of organizing how 1s and 0s are sent (start bit, data bits, optional parity, and stop bit, all at an agreed upon baud rate). To send data to the robot, the transmitter (computer + headphones) encodes 1s as tone (9876Hz) and 0s at another frequency (12345Hz). So for the decoding circuit all you really need are 3 stages: a microphone, an amplifier (opamp chip), and something that can very tightly look to see if the 0s frequency (12345Hz) is present since UART rests high when idle. A phase locked loop (PLL) is excellent for frequency locking, but can be a little hairy to use. The LM567 tone decoder chip however has a PLL inside but is a simple chip to work with. A little variable resistor next to the tone decoder is used to precisely dial in the frequency. Lots of other resistors and capacitors in there to hook everything together, but that's essentially it. Does that make sense? Happy to answer more questions if you have any :) Circuit schematic for reference here: http://research.kumpf.cc/2015-ProgrammingWithHeadphones/imgs/CannyCircuit.png http://research.kumpf.cc/2015-ProgrammingWithHeadphones/imgs...
  - deleted 11y ago
    [deleted]
  - sprobertson 11y ago
    Ah that does make sense! On first read I thought there was some other level of processing, like converting specific tones into bytes (9520Hz -> 0x42). You're translating the pulses directly to and from bits, which seems more sane.
akumpf 11y ago
Another interesting write-up about Canny on IEEE Spectrum: http://spectrum.ieee.org/automaton/robotics/diy/canny-robot-rocks-out-to-audio-programming http://spectrum.ieee.org/automaton/robotics/diy/canny-robot-... Would love to hear thoughts from other engineers and designers oabout where you think a programming interface like this could lead.

16 points by akumpf 11y ago

Direct link to video here: https://www.youtube.com/watch?v=780A0cv1qgA https://www.youtube.com/watch?v=780A0cv1qgA Any comments or questions about how the robot/audio programming works are more than welcome :)

hellbanner 11y ago
Yes, is it binary.. ?
- akumpf 11y ago
  The audio used to program the robot is analog (tones in the form of sine waves), but the data itself modulating the tone is binary. More specifically, it's AFSK. See the diagram/info on the Wikipedia page about for a more detailed explanation. https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_FSK https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_F...

sprobertson 11y ago

Could you go into more detail about how the main decoding circuit works? How does it turn an audio signal into UART?

akumpf 11y ago
Serial/UART is just a simple way of organizing how 1s and 0s are sent (start bit, data bits, optional parity, and stop bit, all at an agreed upon baud rate). To send data to the robot, the transmitter (computer + headphones) encodes 1s as tone (9876Hz) and 0s at another frequency (12345Hz). So for the decoding circuit all you really need are 3 stages: a microphone, an amplifier (opamp chip), and something that can very tightly look to see if the 0s frequency (12345Hz) is present since UART rests high when idle. A phase locked loop (PLL) is excellent for frequency locking, but can be a little hairy to use. The LM567 tone decoder chip however has a PLL inside but is a simple chip to work with. A little variable resistor next to the tone decoder is used to precisely dial in the frequency. Lots of other resistors and capacitors in there to hook everything together, but that's essentially it. Does that make sense? Happy to answer more questions if you have any :) Circuit schematic for reference here: http://research.kumpf.cc/2015-ProgrammingWithHeadphones/imgs/CannyCircuit.png http://research.kumpf.cc/2015-ProgrammingWithHeadphones/imgs...
- deleted 11y ago
  [deleted]
- sprobertson 11y ago
  Ah that does make sense! On first read I thought there was some other level of processing, like converting specific tones into bytes (9520Hz -> 0x42). You're translating the pulses directly to and from bits, which seems more sane.

akumpf 11y ago

Another interesting write-up about Canny on IEEE Spectrum: http://spectrum.ieee.org/automaton/robotics/diy/canny-robot-rocks-out-to-audio-programming http://spectrum.ieee.org/automaton/robotics/diy/canny-robot-... Would love to hear thoughts from other engineers and designers oabout where you think a programming interface like this could lead.