Utility to remind you to keep a task diary

Here's a program that asks you every hour what you are doing, so you end up with a diary at the end of the day. It saves your input to a text file WhatAmIDoing.txt in the same folder you put the exe.

The "ask every hour" button creates a Windows Scheduled Task. Note that if you move the location of the exe file, you will need to click the "ask every hour" button again.

https://acoby.com/utils/WhatAmIDoing.exe

Mailing list manager

I needed a simple mailing list manager for a sports club I'm in. We wanted it to be of the type where an administrator manages the lists (not the type where any random person can subscribe him- or herself). Couldn't find any decent looking free service offering this, so I decided to make one: mailgroup.io .

These are its features:

• Free for noncommercial use.
• Your own custom domain.
• Or @mailgroup.io as domain if you prefer.
• Your choice of members-only mailing lists, or everyone-may-write.
• Detailed Postfix delivery reports for each mail for each recipient.
• Max 50 recipients per account (negotiable).
• Mail triggers. These are special email addresses that trigger HTTP POSTs with the email content to a defined URL when they receive email. Useful if you want some logic on your website to be triggered by email.

GLaDOS-like sound pack for Taranis

Here's a soundpack for the FrSky Taranis, based on the original, but run through Melodyne so it sounds like GLaDOS from Portal: https://acoby.com/fpv/gladosStyleTaranisSounds.zip

Heap sort implementation in C#

Here's a heap sort implementation in C#:

class HeapSort
{
    public void Sort(int[] a)
    {
        // Turn the array into a max heap
        for (int i = (a.Length / 2) - 1; i >= 0; i--)
        {
            MaxHeapify(a, i, a.Length);
        }

        // Remove the largest element from the max heap and put it on the end,
        // and then max heapify the heap which is now 1 smaller
        for (int i = a.Length - 1; i >= 1; i--)
        {
            Swap(a, 0, i);
            MaxHeapify(a, 0, i);
        }
    }

    private void MaxHeapify(int[] a, int i, int n)
    {
        int idxLeft  = (i + 1) * 2 - 1;
        int idxRight = (i + 1) * 2 - 1 + 1;

        int largest = i;

        if (idxLeft < n && a[idxLeft] > a[largest])
        {
            largest = idxLeft;
        }

        if (idxRight < n && a[idxRight] > a[largest])
        {
            largest = idxRight;
        }

        if (largest != i)
        {
            Swap(a, i, largest);
            MaxHeapify(a, largest, n);
        }
    }

    private void Swap(int[] a, int i, int j)
    {
        int tmp = a[i];
        a[i] = a[j];
        a[j] = tmp;
    }
}

Segment tree implementation in Java

Inspired by Kartik Kukreja's implementation, but storing all data in a tree node class, rather than an array. I find it a lot easier to comprehend this way.

class SegmentTreeNode {
    public int aggregateValue;
    public SegmentTreeNode left;
    public SegmentTreeNode right;
    public int origLowIndex;
    public int origHighIndex;
}

class SegmentTreeTest {

    public static SegmentTreeNode buildSegmentTree(int[] a, int low, int high) {
        SegmentTreeNode n = new SegmentTreeNode();
        n.origLowIndex = low;
        n.origHighIndex = high;

        if(low == high) {
            n.aggregateValue = a[low];
            return n;
        }

        int mid = (high - low)/2 + low;

        n.left = buildSegmentTree(a, low, mid);
        n.right = buildSegmentTree(a, mid+1, high);

        // This segment tree is for summation. Could also be min, max, or any other associative func.
        n.aggregateValue = n.left.aggregateValue + n.right.aggregateValue;

        return n;
    }

    public static SegmentTreeNode getAggregateValue(SegmentTreeNode n, int low, int high) {
        if(n.origLowIndex == low && n.origHighIndex == high) {
            return n;
        }

        // The interval is fully contained within the left node
        if(low >= n.left.origLowIndex && high <=  n.left.origHighIndex) {
            return getAggregateValue(n.left, low, high);
        }

        // The interval is fully contained within the right node
        if(low >= n.right.origLowIndex && high <=  n.right.origHighIndex) {
            return getAggregateValue(n.right, low, high);
        }

        // Split into queries on the left subtree and the right subtree
        SegmentTreeNode leftResult = getAggregateValue(n.left, low, n.left.origHighIndex);
        SegmentTreeNode rightResult = getAggregateValue(n.right, n.right.origLowIndex, high);
        SegmentTreeNode result = new SegmentTreeNode();
        result.origLowIndex = low;
        result.origHighIndex  = high;

        // This segment tree is for summation. Could also be min, max, or any other associative func.
        result.aggregateValue = leftResult.aggregateValue + rightResult.aggregateValue;

        return result;
    }

    public static void update(SegmentTreeNode n, int index, int val) {
        if(n.origLowIndex == index && n.origHighIndex == index) {
            n.aggregateValue = val;
            return;
        }

        if(n.left.origLowIndex <= index && index <= n.left.origHighIndex) {
            update(n.left, index, val);
        } else {
            update(n.right, index, val);
        }

        // This segment tree is for summation. Could also be min, max, or any other associative func.
        n.aggregateValue = n.left.aggregateValue + n.right.aggregateValue;
    }

    public static void main(String[] args) {
        //                    0  1  2  3  4  5  6  7  8   9  10
        int[] a = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
        SegmentTreeNode r = buildSegmentTree(a, 0, a.length-1);
        System.out.println(r.aggregateValue);

        System.out.println(getAggregateValue(r, 1, 3).aggregateValue);
        System.out.println(getAggregateValue(r, 4, 7).aggregateValue);

        update(r, 2, 10);
        System.out.println(r.aggregateValue);

        System.out.println(getAggregateValue(r, 4, 7).aggregateValue);
        System.out.println(getAggregateValue(r, 1, 3).aggregateValue);
    }
}

Windows scheduled task to auto logoff

Here's some PowerShell to remotely schedule a task to log out 2+ hours idle users:

function InstallAutoLogoff($computer)
{
    invoke-command -computer $computer `
    {
        schtasks.exe /delete /tn AutoLogOff /f 2>&1 | Out-Null

        set-content c:\windows\temp\AutoLogOffTask.xml `
        '<?xml version="1.0" encoding="UTF-16"?>
        <Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
          <Triggers>
            <TimeTrigger>
              <Repetition>
                <Interval>PT30M</Interval>
              </Repetition>
              <StartBoundary>2015-01-01T00:00:00</StartBoundary>
            </TimeTrigger>
          </Triggers>
          <Actions Context="Author">
            <Exec>
              <Command>PowerShell.exe</Command>
              <Arguments>-Command $r1 = quser.exe; $idPos = $r1[0].IndexOf(''ID  ''); foreach($row in $r1) { $r2 = $row.Substring($idPos).Trim() -split ''  +''; if($r2[2].Contains('':'')) { $t = $r2[2].Replace('':'', ''.''); if($t.Contains(''+'') -or ($t -as [double] -ge 2)) { rwinsta.exe $r2[0] } } }</Arguments>
            </Exec>
          </Actions>
        </Task>'

        schtasks.exe /create /tn AutoLogOff /ru system /xml c:\windows\temp\AutoLogOffTask.xml
        del c:\windows\temp\AutoLogOffTask.xml
    }
}

InstallAutoLogoff 'myserver1'
InstallAutoLogoff 'myserver2'
InstallAutoLogoff 'myserver3'

VoCore OpenWRT as NAT access point

I recently bought a VoCore. It came pre-flashed with OpenWRT Chaos Calmer (as of 2015-03-16). OpenWRT was configured as a wireless access point, bridging with the ethernet port. Here is what I did to get it to a configuration where it acts as a NAT'ing wireless access point, similar to most consumer routers/access points:

SSH'ed to its default IP of 192.168.61.1.

Edited /etc/config/network:

...
#config interface 'lan'
config 'interface' 'wan'
      option macaddr 'b8:d8:12:60:00:01'
      option proto 'dhcp'

config interface 'lan'
  option force_link '1'
  option macaddr 'b8:d8:12:60:00:02'
  option proto 'static'
  option ipaddr '192.168.61.1'
  option netmask '255.255.255.0'
...

Edited /etc/config/wireless:

...
config wifi-iface
      option device   radio0
      option network  lan
      option mode     ap
      option ssid     gaffel8080
      option encryption psk2
      option key palle123
...

Edited /etc/config/dhcp:

...
#config odhcpd 'odhcpd'
# option maindhcp '0'
# option leasefile '/tmp/hosts/odhcpd'
# option leasetrigger '/usr/sbin/odhcpd-update'
...

To enable SSH from the ethernet port, I also edited /etc/config/firewall:

...
config rule
      option src wan
      option proto tcp
      option dst_port 22
      option target ACCEPT

This was all that was needed for the basic scenario of using VoCore as an accesspoint combined with a NAT'ing router.

I went a little further and installed some nice to have packages like openssh-sftp-server, nano, htop, ip, etc. However, in order to do this, I first had to fix /etc/opkg.conf:

...
#src/gz cheese_base http://downloads.openwrt.org/snapshots/trunk/ramips/packages/base
#src/gz cheese_luci http://downloads.openwrt.org/snapshots/trunk/ramips/packages/luci
src/gz chaos_calmer_base http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/base/
src/gz chaos_calmer_luci http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/luci/
src/gz chaos_calmer_management http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/management/
src/gz chaos_calmer_packages http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/packages/
src/gz chaos_calmer_routing http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/routing/
src/gz chaos_calmer_telephony http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/telephony/

After that I could install the extra packages by running the following:

opkg update
opkg install openssh-sftp-server
opkg install nano
opkg install htop
opkg install ip

Also, I recommend disabling Luci, as it is buggy, and a security concern:

rm /www/cgi-bin/luci
echo "A private box" > /www/index.html