Android Find devices on local network

Question

I am trying to map the local network to see how many devices (particularly a device I have built) there are on the network and what IP addresses they have. There are a few methods on this that I have found:

List devices on local network with ping

Android Scan Local Subnet

Why does InetAddress.isReachable return false, when I can ping the IP address?

How do I test the availability of the internet in Java?

The last link is the one I have been able to get working, but it is not very reliable (at least not my implementation of it). When I run the code on my phone it will rarely detect my device (only a few out times of dozens of attempts) on the network.

The device is a TI CC3200 that I have setup as a webserver. I am able to reliably ping the CC3200 with my laptop and I can access the webpage on it nearly 100% of the time using my laptop, phone browser, or using WebView in the app.

I have a serial link with the CC3200 and I can see that the app connects to the CC3200 while it is scanning the network.

I am I doing something incorrect? or is there a better method of mapping the local network that I should focus my effort on?

public boolean scan(final String IP) {
    Globals success = Globals.getInstance();
    success.setDataString(IP);
    Thread thread = new Thread(new Runnable() {
        @Override
        public void run() {

            try {
                Globals success = Globals.getInstance();

                URL url = new URL("http://" + IP);
                URLConnection conn = url.openConnection();
                conn.setConnectTimeout(2000);
                conn.setReadTimeout(2000);

                InputStream in = conn.getInputStream();
                success.setDataBool(true);
            } catch (SocketTimeoutException e) {
                Globals success = Globals.getInstance();
                success.setDataBool(false);
                e.printStackTrace();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    });

    thread.start();
    //boolean temp2 = success.getDataBool();
    return success.getDataBool();
}
}