Week 9 - Input Devices

Chintan Vaishnav


I am interested in building both Step reponse and Temperature sensors. These are most relevant to the sensors I am trying to build for agriculture as a part of my final project.


I built the "load" version of the Step Response. Milling, soldering, and downloading software worked just fine. The current challenges are the following:

  • Pythone terminal hangs talking to my board no Mac, and Ubuntu.
  • The board does not seem to send back "1,2,3,4" sequence. If I comment this part of the code, the pythone termina works, but not sure what its reading.
  • The oscillscope shows expected signals on PB3 (charge pin), and PB4 (sense signal). PB2 (output pin, which the termina reads), has a pulse train that does not seem to change even when sense signal changes.
  • Wondering if the software on the chip is executing right?
  • Fix

    The problem was with the baud rate at which the board sent information (sensor readings) up to the computer. The samplnig rage at which the computer expected the input (using FTDI) was slightly different from the rate at which board sent the info. Play with the definition of bit_delay_time (#define bit_delay_time) by changing the value to 100+/-2 in hello.load.45.c. Here is my heavily commented version of hello.load.45.c.

    I can now produce the following output on my screen.

    Input from step response