Windows Mobile – the no-go world of Function Keys


I want to summarize the role of function keys in Windows Mobile, former Pocket PC, as I got several questions each week on how to use or enable Function keys in this or that application.

Here is a simple information about how function keys work in Windows Mobile.

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COVID-19 Infektionen in Deutschland

Auf meinem Github Account habe ich eine Bash Script Sammlung hinterlegt, mit der man die aktuellen COVID-19 Zahlen schnell in einem Plot sehen kann.

Die bereits verfügbaren grafischen Darstellungen waren mir in meinem Browser zu langsam. Deshalb habe ich meine eigene Darstellung mit Hilfe von Bash und GNUPlot erstellt:

How I run two openvpn server in same private network

I am running two openvpn servers in private network ( Only in case one server stops working.


default gateway internet router:
openvpn1:, debian, bananapi m2
openvpn2: old= new=, debian, bananapi B2
web server1: (static ip), also running unbound dns and dnsmasq as DHCP server, debian
web server2: (static ip), enigma2


First, both openvp servers where configured the same, using for the remote clients. Do not forget to enable ip4 forwarding: sudo sysctl -w net.ipv4.ip_forward=1.

Unfortunately, some hosts did not respond, when connected to the second openvp server. Don’t know, why openvpn server1 works for remote connections connecting to private web servers. Internet browsing using default router worked with both opvpn connections.

When running a ssh session on .137 or .143, I was able to ping .40, but could not browse to the .40 web server from the remote connection. When connected to openvpn2, I could not open the web page of the server.

How does a host know to use correct vpn network for sending back traffic and do not use the default router?


I changed the configuration to openvpn2 to use Then I tested with static routes on

For the static ip (/etc/network/interfaces):

  post-up route add -net gw dev eth1
  post-up route add -net gw dev eth1

After that temporary change on .40, I was able to to connect to openvpn2 and the web server on .40.

For dhcp clients in network (many esp8266, esp32 and esplink devices), I need to have an option for DHCP too.

On the dnsmasq dhcp server:


Note that the default router option (dhcp-option=option:router, may be ignored by dhcp clients

The dhcp options have been verified on a debian client:

aoa150:~$ ip r
default via dev wlan2 proto static metric 600 via dev wlan2 proto dhcp metric 600 via dev wlan2 proto dhcp metric 600 dev wlan2 proto kernel scope link src metric 600

Now I can connect from my mobile using OpenVPN to my network using openvpn1 and openvpn2 server.

adsbox, dump1090 piaware flightaware flightradar24 and IPv6

Recently I switched by flight tracker Bananapi M2 Zero with RTLSDR from adsbox (port 7070) to dump1090 (port 8080). But then, the IPv6 official address does not open the web site any more, although I switched the port forarding from 7070 to 8080 on the router.

After some digging and tests, I found that lighttpd, that was used as web server by dump1090-fa (fligh-warae variant), does not default to use IPv6 too. I had to change the dump1090-fa extension for lighttpd to:


...# Listen on port 8080 and serve the map there, too.
$SERVER["socket"] == ":8080" {
  server.use-ipv6 = "enable"
  alias.url += (
    "/data/" => "/run/dump1090-fa/",
    "/" => "/usr/share/dump1090-fa/html/"

Now,  netstat -tulpn did show that port 80 and 8080 are open for ipv4 and ipv6

tcp        0      0    *               LISTEN      -                   
tcp6       0      0 :::8080                 :::*                    LISTEN      -

Just to remember.

LED candle light with timer


I did a lot of research on battery powered LED candle lights circuits and code and was unable to find a time controlled LED candle light.

As I have some ATTiny13 left, I decided to use this little chip. As I want the LED to do a candle light for about 4hours and then stay of for another 20 hours, I need on timer and counter. Another timer/PWM is needed to immitate a candle flickering. But the ATTiny13 has only one timer. On the ATTiny13 you can either use the timer or PWM.

Fortunately the ATTiny has also a Watchdog timer that can be used to call an interrupt function. The watchdog runs with a separate 128kHz clock, independent from the CPU clock. The largest timeout is 8 seconds. So I need to count this 450 times to have one hour.

// watchdog interrupt
ISR (WDT_vect)

  //flash heart beat LED
  digitalWrite(LED2, HIGH);
  digitalWrite(LED2, LOW);
        bLedIsOn=0; //switch to OFF mode
        bLedIsOn=1; //switch to ON mode
}  // end of WDT_vect

The code makes the ATTiny13 sleep for another 8 seconds or light the LED. The ON phase is 4 hours and the sleep phase will be extended to 20 hours.

void loop ()
  //sleep 20 hours and work 4 hours
    digitalWrite (LED, LOW); //ensure LED is OFF
   goToSleep ();
}  // end of loop

The sequence starts with the ON phase, when power is applied. In the ON phase I measure about 3mA and in the OFF phase the circuit needs 300µA.

The circuit is documented in the Arduino code file. Running the ATTiny13 at lower clock than 9.6MHz did not change the power usage. But I switched to the 1.2MHz internal clock and disabled BOD (auto power down for low power) to get a longer runtime with two or three AA batteries.

UPDATE 2019/03/10: The wdt calculation is wrong and I changed the 450 cycles for one hour to 388. See github README for full update. The main issue is that the ATTiny13 datasheet says 128kHz but means 131072Hz and not 128000Hz and the wdt oscilator never cycles that fast but more or less at around 113000Hz.

CREDITS to all that share their knowledge, especially: