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    The Learning Circuit
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    Bob Baddeley returns to continue helping Ben automate his workbench using Alexa and Raspberry Pi.   They’ve already gotten Alexa up and running, talking to a microcontroller over USB.  Now it's time to automate everything else in the shop.  They’ll use a multimeter and get a reading from it, they’ll go over the network connection to the oscilloscope so that they can change its settings and take screenshots with voice commands. They will interface a Gert Board with the GPIO on the Pi so they can turn bits on and off. 



    The Fluke Multimeter has an IR port on the top, so when they plug it into a device, it shows up as a regular serial port.   They hook it up to the terminal on the Raspberry Pi to determine what steps to take next.  The data returned depends on what mode the multimeter is in.  They’ll need to parse the data to see what they care about and send it back over the JsonResponse.  They are asking the python script to send a serial signal to the multimeter to request the reading, and then they take the response back and send it to their PHP script.  The PHP script takes that response then takes that response and splits it up into the individual comma separated values.  They’ll take the data sheet for the multimeter and convert it into its actual readings, pulling out the values that they care about. They’ll need to parse the data ain order for Alexa to pronounce the information correctly.   As it turns out, the Fluke has an internal reading that it sends over the serial port that is different from what it displays on the screen.  They’ll need to do some quick conversions in their PHP script to accommodate that.

    Next, they’ll automate their MD0-3106 Tektronix a oscilloscope using a list of commands from a datasheet.  They’ll use Putty to set up a telnet connection with their oscilloscope.  Unlike the multimeter, you can control pretty much anything on an oscilloscope using tel-net commands. They can even reuse the code from the multimeter using different intents such as stop, run, save zoom, pan, scale, single, auto set, and repeat. Bob goes over the code they are using with Ben.  Alexa interprets voice and sends that to their Apache server which is running PHP, the PHP is calling Python which then goes down to the scope, and the Scope interprets.

    After testing the oscilloscope commands they move onto the Gert board. Before plugging into the Alexa API they draw everything out on a whiteboard.  Ben sets up a skill that has an intent of set to allow them to set a specific pin while Bob sets puts a table in python.  Wiring Pi has been deprecated so they’ll need to use RPi.GPIO.  Alexa is now able to set pins hi and low or on and off.