rpi

Amazon Dash Button Fun

Standalone: Raspberry Pi

We will configure a Raspberry Pi to act as access point for the dash button. Similar to the openWRT solution, this gives us full control over the button's communication. The Raspberry Pi will be connected to the internet through the ethernet port and provide a WiFi access point through a WiFi adapter.

All scripts run on the Raspberry Pi and no server/computer is needed to interact with the button.

Advantages

• no dependencies
• no connection to Amazon
• no router modifications needed

Disadvantages

• requires hardware (RPi + WiFi Dongle)

Configuration

1. Install Raspbian Jessie Lite.

2. Install required packages sudo apt-get install hostapd dnsmasq isc-dhcp-server

3. Get a WiFi adapter that is compatible with the Raspberry Pi. I used a Netgear WNA1000M N150 Micro Adapter. It has a Realtek RTL8192CU chipset. If your chipset is supported out-of-the-box, skip the next step.

4. Install the modified hostapd version from Realtek. Either take the binary hostapd from this repository, or follow these steps to build it yourself.

   • Download the RTL8192CU driver from Realtek: http://www.realtek.com/downloads/downloadsView.aspx?Langid=1&PNid=21&PFid=48&Level=5&Conn=4&DownTypeID=3&GetDown=false&Downloads=true#2772
   • Navigate to RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911/wpa_supplicant_hostapd/ and extract wpa_supplicant_hostapd-0.8_rtw_r7475.20130812.tar.gz
   • navigate to wpa_supplicant_hostapd-0.8_rtw_r7475.20130812/hostapd/ and build with make.
   • remove the installed hostapd binary sudo mv /usr/sbin/hostapd /usr/sbin/hostapd.orig
   • install the new hostapd binary sudo cp hostapd /usr/sbin/hostapd

5. Configure hostapd by creating the file /etc/hostapd/hostapd.conf with the following contents (if you don't have the RTL8192CU chipset, replace rtl871xdrv with nl80211)

    interface=wlan0
    driver=rtl871xdrv
    ssid=DashIoT
    channel=1
    auth_algs=1
    wmm_enabled=0
    wpa=1
    wpa_passphrase=yourpassword
    wpa_key_mgmt=WPA-PSK
    wpa_pairwise=CCMP
    macaddr_acl=0
   

6. Configure the WiFi adapter in /etc/network/interfaces to use the 192.168.50.x network. It should look like this

    auto lo
    iface lo inet loopback
    
    iface eth0 inet manual
    
    iface wlan0 inet static
        address 192.168.50.1
        netmask 255.255.255.0
    
    hostapd /etc/hostapd/hostapd.conf
   

7. Configure the DHCP server in /etc/dhcp/dhcp.conf. It should look like this

    default-lease-time 600;
    max-lease-time 7200;
    option routers 192.168.50.1;
    option domain-name-servers 192.168.50.1, 192.168.50.1;
   
    subnet 192.168.50.0 netmask 255.255.255.0 {
            pool {
                    max-lease-time 600;
                    range 192.168.50.10 192.168.50.50;
                    option routers 192.168.50.1;
                    option domain-name-servers 192.168.50.1, 192.168.50.1;
                    allow unknown-clients;
            }
    }
   

8. Disable Google's DNS server

    sudo iptables -t nat -I PREROUTING -j DNAT --destination 8.8.8.8 --to 192.168.50.1
    sudo iptables -t nat -I PREROUTING -j DNAT --destination 8.8.4.4 --to 192.168.50.1
   

9. Enable NAT:

    sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
    sudo iptables -A FORWARD -i eth0 -o wlan0 -j ACCEPT
    sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT
   

10. Enable IPv4 forwarding. Add following line to /etc/sysctl.conf:

    net.ipv4.ip_forward=1
    

11. Make the rules persistent by installing iptables-persistent: sudo apt-get install iptables-persistent

12. Reboot the Raspberry Pi (sudo reboot)

13. You should be able to connect to the access point with any wireless device.

14. Activate your Dash button using the Amazon app. You can abort the activation at the point where you have to select a product.

15. Redirect the Amazon endpoint to the Raspberry Pi by adding the following line to /etc/dnsmasq.conf:

    address=/parker-gw-eu.amazon.com/192.168.50.1
    

16. Restart dnsmasq: sudo service dnsmasq restart

Listening for button presses

All the tools from the openWRT setup also work with the Raspberry Pi setup. Just run sudo python openwrt/listen.py to test the setup. Every time the button is pressed, the MAC address of the button is displayed.