Tutorial: Connecting Hologram Nova directly to Google Cloud Platform (Firebase)

Here’s how I connected my Hologram Nova to the Google Cloud Platform (Firebase).

Project Background:

I have a Raspberry Pi with physical sensors plugged in. A Python 3 script reads the sensors and is responsible for sending the data to my Firebase database. In this tutorial, I’ll be hardcoding the sensor values for simplicity (fill in your sensor functions here).

Solution Overview:

  • we’ll create a Firebase database
  • then we’ll get the credentials to write to Firebase (either with a REST call or with Firebase’s Python library)
  • next, it’s time to code, and we’ll set up a Point-to-Point Protocol connection
  • finally, we’ll write from our Nova directly to Firebase

Firebase Setup:

  • firebase.google.com > “go to console” > “add project”
  • enter a project name > (unselect A/B testing) > “create project” > “continue”
  • click the “Web” icon next to the phrase “Add an app to get started”
  • enter an app name (any name will do; you’ll never reference this again) > “register”
  • copy the firebaseConfig variable for later use > “continue to console”
  • in the left column, under Build > Firestore database > “create database” > “start in test mode” > “next”
  • choose a physical location for your database under “Cloud Firestore location” (reference: https://cloud.google.com/compute/docs/regions-zones) > “enable”

You should now be in the Build > Firestore database > Data tab, which is where you’ll be able to see your data stream in!

Authentication Setup:

  • There are 2 ways to authenticate:
  1. with a web API key for REST calls
  2. integrating the firebaseConfig variable that you copied above

For this tutorial, I’m going to show the REST approach because it’s generic, and because the firebaseConfig way needs to be integrated into your specific platform, and there are many tutorials for that on YouTube already.

To generate a web API key, navigate to Google Cloud Platform > (hamburger menu) > APIs & Services > Credentials > Create Credentials > API key > (copy the string)

PPP Setup:

Here’s an example Python script to enable PPP. Manually turn Wi-Fi off to verify :slight_smile:

import netifaces                                            # sudo pip3 install netifaces
import requests

ppp_exists = False

    ppp_exists = True
    ppp_exists = False

if ppp_exists == True:
        r = requests.get('https://google.com', timeout=10)  # timeout's necessary in case we can't access the internet
        print(f'status code = {r.status_code}')
        print('no connection')

print(f'PPP status: {ppp_exists}')

Write Directly from a Nova to the Google Cloud Platform:

import requests
import json
import datetime

web_api_key = 'MY_WEB_API_KEY'
collection_name = 'MySensors'
url = f'https://firestore.googleapis.com/v1/projects/{project_id}/databases/(default)/documents/{collection_name}/?key={web_api_key}'

d = datetime.datetime.utcnow()
time = d.strftime("%X")                             # hours:minutes:seconds

payload = {
    'fields': {
        'name': { 'stringValue': 'sensor123' },
        'temperature': { 'doubleValue': 75 },       # NOTE: shorten these names to save on data throughput, ie: 't': {'doubleValue': 75}
        'time': { 'stringValue': time }
headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
response = requests.post(url, data=json.dumps(payload), headers=headers)
# print(f'response = {response.content}')

response_dict = json.loads(response.content)        # print the response in a readable format
for i in response_dict:
    print(f'{i}: {response_dict[i]}')

Thank you, @Reuben for helping me with the PPP interface!

And thanks for reading,

1 Like

Glad you were able to get it all working. Thanks for sharing this great write-up. We can point people here in the future if they have any questions about it

1 Like

I’m glad you liked it!

I’ve got some questions for you. Maybe I can email you, and if I make headway, I’ll update this tutorial.

Basically, something’s eating away at my data, and I’m not sure how to tell where all the traffic’s coming from or how I can stop it.


Hard to say. One thing we always say to check if you’re using PPP is if the device is downloading updates or something behind the scenes. There might be some services running that start using the cellular connection

Thanks, Ruben. Could you point me in the direction of a tutorial you like? PPP is very new to me.


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