Twitter Controlled Anything - Micropython on ESP32

I recently purchased an ESP32 from amazon for testing purposes and a colleague mentioned you could install a minimalist python environment on them for control. To say the least, I was intrigued.

I wanted to be able to control a light (or anything really) using tweets. Below are the instructions/scripts I wrote to get it working. First comes the prerequisites:

• ESP32 (duh)
• A VPS, Pi, or really any computer acting as a flask server (it just needs internet access)
• A wifi network for the ESP32 to connect to, I just used the hotspot on my phone as a PoC
• Twitter API credentials (really easy to get, just fill out the forms)

TLDR:

Your ESP32 will query your flask server for a trigger word to enable the LED. The Flask server will query twitter for your latest top tweet, if it has a trigger word in it, relay that to the esp32 client. Boom, tweet causes LED to turn on.

The first step is to get your ESP32 setup running the micropython environment. I followed this excellent guide. 

Once you get your ESP32 configured to run python code, go ahead and transfer the following script to act as the client. You just need to change the wifi details and target flask server:

import machine
import urequests
import time

pin = machine.Pin(2, machine.Pin.OUT)

def connect():
    import network
    sta_if = network.WLAN(network.STA_IF)
    if not sta_if.isconnected():
        print('connecting to network...')
        sta_if.active(True)
        sta_if.connect('WIFINETWORKSSIDHERE', 'WIFIPASSWORDHERE')
        while not sta_if.isconnected():
            pass
    print('network config:', sta_if.ifconfig())

def no_debug():
    import esp
    # this can be run from the REPL as well
    esp.osdebug(None)

no_debug()
connect()

while True:
    time.sleep(2)
    if 'yes' in urequests.get('http://MYFLASKDOMAINHERE.com:5000').text:
        pin.value(1)

Connect the LED to Pin 2 on the ESP32 and it's all set to go. Now onto the flask server...

On your VPS/Pi/whatever, install flask and tweepy and create a directory to hold your script files. Grab the Access Token, Access Secret, Consumer Secret, Consumer Key from your Twitter Dev console that you set up earlier and place them in a "twitter_creds.py" file like the following:

ACCESS_TOKEN = '18077065-lakjsdflkajshdlfkajshdflkajsdhqqSYOtHSXtK1'
ACCESS_SECRET = 'hPqlkwjehrlkfjnlqwejhqrwklejrqhlwkejrJr1'
CONSUMER_KEY = 'QZlk9qlkwejrhqlkwjerhlqwlLh'
CONSUMER_SECRET = 'uEnkzjxcnvluqblwjbefkqwlekjflkqjwehflqlkjhuOE'

Then paste the following into "tweepy-top.py"

from twitter_creds import *

import tweepy

auth = tweepy.OAuthHandler(CONSUMER_KEY, CONSUMER_SECRET)
auth.set_access_token(ACCESS_TOKEN, ACCESS_SECRET)

api = tweepy.API(auth)

def get_top_tweet():
    top_tweet = api.user_timeline(count=1)
    return top_tweet[0].text

Now create your main flask app by pasting the following into "flaskhello.py":

from flask import Flask
from tweepy_top import get_top_tweet

app = Flask(__name__)

@app.route("/")
def hello():
    if 'light' in get_top_tweet():
        return 'yes'
    else:
        return 'no'

if __name__ == "__main__":
  app.run(host="0.0.0.0", threaded=True)

There you can see 'light' is used as the trigger word. Using this setup, every 2 seconds the esp32 will make a request to your flask server, which causes the flask server to query twitter for the user's top tweet, if the top tweet contains the word "light" in it, it returns the string "yes". The ESP32 recognizes the "yes" and turns on pin 2.

This is a very simple PoC and gets the job done. You can take this and expand in a thousand directions with it, some ideas:

• A desktop counter that keeps track of your followers, retweets, likes, etc
• A LED scroller that outputs your latest mentions
• Or simply use twitter as the control for some device

The options are endless...enjoy :D

Configure Static Wifi Card Interface Names in Kali

I've always hated having to correlate the mac address of wlanX with whats printed on the sticker of the device (if it is at all) to find out which adapter is which in kali. Turns out you can can create static entries that tie to the MAC address of the adapter. Below are the steps:

1. Plug in your device, make sure it shows up in kali with ifconfig/iwconfig (probably as wlan1...)
2. Note the MAC address of the alfa card (or w/e card you have)
3. open /etc/udev/rules.d/70-persistent-net.rules and look for the entry corresponding to the MAC you noted. It should look something like this:
   • # USB device 0x:0x (rt2800usb)
   • SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:c0:ca:87:5b:27", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan1"
4. change "wlan1" to "alfa1" or whatever naming scheme you want, save the file
5. unplug, replug
6. dmesg should say:
   • [ 1341.218253] systemd-udevd[2381]: renamed network interface wlan0 to alfa1
7. repeat with your next wifi adapter

That's it. You're basically just editing it's udev entry to have a different name. This persisted past several reboots and recognizes multiple different cards plugged in at once. You can use these new names exactly the same way as the old ones:

# iwconfig alfa1

alfa1     IEEE 802.11abgn  ESSID:off/any  

          Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   

          Retry short limit:7   RTS thr:off   Fragment thr:off

          Encryption key:off

          Power Management:off

I took a label maker I had laying around and printed out "alfa1, alfa2, tpl1, etc" and stuck them to the adapters themselves. Now I can find which adapter I need just by glancing at the spaghetti mess of wires and adapters.