Radio control car that recognizes words

Make things

Let’s make the radio control car that moves by recognizing words.


How to make

Hardware Connection

Wire as shown in the table and figure below.
Note that the DC Motors orientation. It changes tire rotation direction.

obniz DC Motor
0 Left DC Motor OUT1
1 Left DC Motor OUT2
10 Right DC Motor OUT2
11 Right DC Motor OUT1

Make the car body so that obniz and Battery can ride on.


Get the api key of “Google Cloud Vision API”

This application uses Google Cloud Vision API. So you need your own API key.
Follow this official document and get the API key.

When you use this application, copy and paste the API key the area shown in this image:

Use Google Cloud Vision API

By using Google Cloud Vision API, you can easily do image analysis with POST request.
It has many variation of analysis, but this time we use text detection API.

When you use this API, note that the image must be encoded in Base64 format.

var base64Img = BASE64_IMAGE;
// get API key
var apiKey = document.getElementById("google_api_key").value;
var body = {
  "requests": [{
    "image": { "content": base64Img },
    "features": [
      { "type": "LABEL_DETECTION" },
      { "type": "TEXT_DETECTION", "maxResults": 1 }
//request to google api
fetch("" + apiKey,
    body: JSON.stringify(body),
    method: 'POST',
    headers: { 'Content-Type': 'application/json' }
).then(function (response) {
  // process for the response

Correspondence between the word and the movement

Word Movement
go Go forward
back Go back
stop Stop
right Turn to the right
left Turn to the left
here Go to the position of the word