From 1d13ce7ef927bb92d5ddd98adc11e4481980b80a Mon Sep 17 00:00:00 2001
From: Joe Shaw <joe@joeshaw.org>
Date: Fri, 21 Aug 2015 11:54:34 -0400
Subject: [PATCH] the Salt Mines gyro button

---
 .gitignore |  1 +
 README.md  | 24 ++++++++++++++++++++++++
 gyro.go    | 45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100644 gyro.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a924640
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+gyro
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..795f17a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+## Gryo Button
+
+When you press the button on an Amazon Dash, we increment the Salt
+Mines gyro counter.  See the current count [on the
+dashboard](http://dashboard.saltmines.us/south).
+
+Inspired by [this article by Ted
+Benson](https://medium.com/@edwardbenson/how-i-hacked-amazon-s-5-wifi-button-to-track-baby-data-794214b0bdd8).
+
+## Development and deployment
+
+This runs on the Raspberry Pi in the office.  I develop it on my Mac
+and cross compile it for linux/arm.  You will need Go with the
+linux/arm toolchain.  If you're on a Mac, this is easy:
+
+    $ brew install --with-cc-common go
+
+Once that's done:
+
+    $ GOOS=linux GOARCH=arm go build
+
+Then scp the `gyro` binary to `pi@dash1.local` and run it:
+
+    $ sudo ./gyro wlan0
diff --git a/gyro.go b/gyro.go
new file mode 100644
index 0000000..501c5dd
--- /dev/null
+++ b/gyro.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"log"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+
+	"github.com/mdlayher/arp"
+)
+
+const gyroURL = "http://saltmines.us/gyroup.php"
+const name = "Some button pusher"
+
+func main() {
+	if len(os.Args) < 2 {
+		log.Fatal("Usage: arp <iface>")
+	}
+
+	iface, err := net.InterfaceByName(os.Args[1])
+	if err != nil {
+		log.Fatal("InterfaceByName: ", err)
+	}
+
+	c, err := arp.NewClient(iface)
+	if err != nil {
+		log.Fatal("arp.NewClient: ", err)
+	}
+
+	for {
+		p, _, err := c.Read()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		if p.Operation == arp.OperationRequest && p.SenderIP.Equal(net.IPv4zero) {
+			resp, err := http.PostForm(gyroURL, url.Values{"user_name": {name}})
+			if err != nil {
+				log.Printf("Error updating count: %s", err)
+			}
+			resp.Body.Close()
+		}
+	}
+}