Scott Hanselman

Software Defined Radio is a great way to bridge the physical and the digital and teach STEM

April 25, '19 Comments [7] Posted in Hardware | Open Source
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Software Defined Radio AdapterOne of the magical technologies that makes an Open Source Artificial Pancreas possible is "Software-defined Radio" or SDR. I have found that SDR is one of those technologies that you've either heard of and agree it's amazing or you've literally never heard of it. Well, buckle up, friends

There's an amazing write up by Pete Schwamb, one of the core members of the community who works on Loop full time now, on how Software Defined Radios have allowed the community to "sniff" the communication protocols of insulin pumps in the RF spectrum and reverse engineer the communications for the Medtronic and now Omnipod Eros Insulin Pumps. It's a fascinating read that really illustrates how you just need the right people and a good cause and you can do anything.

In his post, Pete explains how he configured the SDR attached to his computer to listen into the 433MHz range and capture the RF (radio frequencies) coming to and from an insulin pump. He shows how the shifts between a slightly higher and slightly lower frequency is used to express 1s and 0s, just like a high voltage is a 1 and a low or no voltage is a 0.

Radio Frequency to 1s and 0s

Then he gets a whole "packet," plucks it out of the thin air, and then manipulates it from Python. Insert Major Motion Picture Programmer Montage and a open source pancreas pops out the other side.

1s and 0s from RF into a string in Python

Lemme tell you, Dear Reader, Hello World is nice, but pulling binary data out of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light is THE HOTNESS.

From a STEM perspective, SDR is more fun than Console Apps when educating kids about the world and it's a great way to make the abstract REAL while teaching programming and science.

You can get a SDR kit for as little as US$20 as a USB device. They are so simple and small it's hard to believe they work at all.

Just plug it in and download Airspy (Formerly SDRSharp, there are many choices in the SDR space). and run the install-rtlsdr.bat to setup a few drivers.

You'll want to run zadig.exe and change the default driver for listening to radio (FM, TV) over to something more low-level. Run it, select "List All Interfaces," and select "Bulk Interface 0"

Updating SDR wtih Zadig

After you hit Replace Driver with WinUSB, you can close this and run SDRSharp.exe.

I've set my SDRSharp to WFM (FM Radio) and turned the Gain up and OMG it's the radio.

Listening to the Radio with SDR

In this pic I'm listening to 91.5 FM in Portland, Oregon which is National Public Radio. The news is the center red line moving down, while the far right is 92.3, a rock station, and 90.7 on the far left is more jazz. You can almost see it!

AdaFruit has as great SDR tutorial and I'll use it to find the local station for National Weather Radio. This is the weather alert that is available anywhere here in America. Mine was Narrow Band (WFM) at 162.550 FM! It was harder to hear but it was there when I turned up the gain.

The weather report

But wait, it's more than radio, it's the whole spectrum!

Here I am sending a "Get Pump Model" command to my insulin pump in the 900Mhz range! The meaty part is in the red.

Talking to an Insulin Pump

Here's the heartbeat and requests that are sent to my Insulin Pump from my Loop app through a RileyLink (BT to RF Bridge). I'm seeing the Looping communications of my Open Source Artificial Pancreas here, live.

Watching RF Pump Communications

Next post or two I'll try to get the raw bits off of the RF signal of something interesting. If you haven't messed with SDR you should really give it a try! As I said before you can get a SDR kit for as little as US$20 as a USB device.


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Open Source Artificial Pancreases will become the new standard of care for Diabetes in 2019

April 23, '19 Comments [12] Posted in Diabetes
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Loop is an open source pancreas for iPhoneI've been a Type 1 diabetic for over 25 years. Diabetes sucks. They actually give you an award for staying alive for years on insulin. Diabetics don't usually die of old age, they die of heart disease or stroke, kidney failure, and while they're at it they may go blind, get nerve damage, amputation, and a bunch of other stuff. It used to be a death sentence but when insulin was introduced as a treatment in 1921, there was a chance for something new.

The idea is if you keep your blood sugars close to normal - if you can simulate your non-working pancreas - you'll get hit by an ice cream truck! At least, that's how I hope I go. :)

  • Early on it was boiling big gauge steel needles and pork insulin to dose, and peeing on a stick to get a sense of sugar levels.
  • Then it was a dozen finger pricks a day and a half dozens manual shots with a syringe.
  • Then it was inserted continuous glucose meters and insulin pumps that - while not automatic - mean less invasive treatment and greater control.

Today, we are closing the loop. What's the loop? It's this:

  1. Consider my glucose levels, what I'm about to eat, and what I'm about to to (and dozens of other environmental factors)
  2. Dose myself with insulin
  3. GOTO 1. Every few hours, or every few minutes, depending on the situation.

I do that. Manually. Every diabetic does, and the mental pressure - the intense background psychic weight of it all - is overwhelming. We want to lower the cognitive load of diabetes. This is a disease where you may not live as long if you're not good at math. Literally. That's unfair.

The community is "looping" by allowing an algorithm to make some of those decisions for me.

I've personally been looping with an open source artificial pancreas for over two years. It's night and day from where I started with finger sticks and a half dozen needle sticks a day. It's not perfect, it's not automatic, but Open Source Pancreas are "Tesla autopilot for diabetes." It doesn't always park the car right or stop at every stop light, but it works very hard to keep me in-between the lines and going straight ahead and now that I have it, I can't imagine living without it.

I sleep through the night while my Loop makes tiny adjustments every five minutes to keep my sugars as flat as possible. I don't know about you but my pancreas sits on my nightstand.

It's happening and it can't be stopped

Seven years ago I wrote about The Sad State of Diabetes Technology in 2012. Three years ago The Promising State of Diabetes Technology in 2016 and last year The Extremely Promising State of Diabetes Technology in 2018. There's a great comment from the first blog post in 2012 where Howard Loop shared his frustration with the state of things. Unlike most commenters on the Internet, amazingly Howard took action and started the Tidepool Organization! Everything in his comment from 7 years ago is happening.
Great article, Scott. You've accurately captured the frustration I've felt since my 12 year old daughter was diagnosed with T1D nine months ago. She also wears a pump and CGM and bravely performs the ritual you demonstrate in your video every three days. The technology is so retro it's embarrassing.

It's 2019 and things are really looking up. The open source DIY diabetes community is thriving. There are SEVERAL open pancreas systems to choose from and there's constant innovation happening with OpenAPS and Loop/LoopKit.

  • OpenAPS runs on devices like Raspberry Pi Zeros and is a self-contained pancreas with the communications and brain/algorithm all on the main device.
  • Loop runs on an iPhone and uses a "RileyLink" devices that bridges the RF (Radio Frequency) insulin pump communications with modern Bluetooth.

The first bad part is I am running a 15 year old out of warranty cracked insulin pump I bought on Craigslist. Most new pumps are locked down, and my old pump is the last version that supported remote control. However, the Loop open source project announced support for a second pump this week, the OmniPod Eros. This is the first time an "in warranty" pump has been supported and it also proves the larger point made by the diabetes community. We Are Not Waiting. We want open choice and open data and open choices that put us in control.

Read about the history of Loop by original developer Nate Racklyeft. As he points out, a thing like Loop or OpenAPS is the result of a thousand little steps and innovation by countless community members who are so generous with their time.

The first system to run it was a Raspberry Pi; the code was a series of plugins, written with the help of Chris Hannemann, to the openaps toolkit developed by Ben West in collaboration with Dana Lewis and Scott Leibrand. I’m still in awe of the elegant premise in Ben’s design: a system of repeatable, recordable, and extendable transform commands, all backed by Git. The central plugin of the toolkit is decocare: Ben’s 5-year magnum opus, a reverse-engineered protocol of the Minimed Carelink USB radio to command insulin pumps.

There's an amazing write up by Pete Schwamb, one of the core members of the community who works on Loop full time now,  on how Software Defined Radios have allowed the community to "sniff" the communication protocols of insulin pumps in the RF spectrum and reverse engineer the communications for the Medtronic and now Omnipod Eros Insulin Pumps. It's a fascinating read that really illustrates how you just need the right people and a good cause and you can do anything.

You can watch my video presentation "Solving Diabetes with an Open Source Artificial Pancreas" where I offer an overview of the problem, a number solutions offered over the year, and two open source pancreas options in the form of LoopKit and OpenAPS.

The community members and organizations like Tidepool and the Nightscout Foundation are working with the FDA to take projects and concepts like an open source pancreas system from a threat based on years of frustration to a bright future based on mutual collaboration!

In March, 2018, the FDA announced a de novo iCGM (integrated CGM) designation. A de novo designation is the FDA process for creating new device classifications, in this case moving qualifying CGMs from Class-III, the highest FDA risk classification, to Class-II with Special Controls. The first CGM to get this designation is the Dexcom G6.

Diabetic Xbox AvatarWhat does this mean? It means the FDA is willing to classify continuous glucose meters in a formal way that paves a path towards interoperable devices. Today we hack devices to build these Loops with out-of-warranty pumps. We are doing this utterly on our own. It can take months to collect the equipment needed, get ancient pumps on the gray market, compile the software yourself - which is a huge hurdle for the non-technical.

Imagine a future where someone could buy a supported and in-warranty "iPump," download an officially supported app or package, and start looping! We could have world of open and interoperable devices and swappable algorithms.

In October of 2018 the non-profit Tidepool organization announced its intent to deliver the Loop app as a supported and FDA-regulated mobile app in the Apple App Store! This is happening, people but we are just getting started.

To learn more, start reading.

Also, if you're diabetic, consider buying a Nightscout Xbox Avatar accessory so you can see yourself represented while you game!


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Exploring DNS with the .NET Core based Technitium DNS Server

April 18, '19 Comments [12] Posted in DotNetCore
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Earlier this week I talked about how Your Computer is not a Black Box and I spent some time in TCPView and at the command line exploring open ports on my computer. I was doing this in order to debug an issue with a local DNS server I was playing with, so I thought I'd take a moment and look at that server itself.

The Technitium DNS Server is a personal local DNS server (FOSS on GitHub) written in C# and it runs on Windows, macOS, Linux, Raspberry Pi, etc. I downloaded the Portable app.

For Windows folks who aren't used to .tar.gz files, remember to "eXtract Zie Files!" with "tar -xzvf DnsServerPortable.tar.gz -C ./TechnitiumDNS/" and it's also worth reminding you all that tar.exe, curl.exe, wget.exe and more are all included in Windows 10 and have been since 2017. If that's too hard, use 7zip.

Technitium DNS is pretty cool, you just unzip/tar it and run start.sh or start.bat and it "just works." Of course, I did have a process already on port 53 - DNS - so I did a little debugging, but that was my fault.

Here's the local web UI that you can use to administer the server locally. You can forward to whatever upstream DNS server you'd like, with the added bonus that the forwarder can be DNS over HTTPS so you can use things like CloudFlare, Google, or Cloud9. Using DNS over HTTPS means your DNS lookups can be secured with DNSSEC and are far more secure and private than regular DNS over UDP/TCP.

Technitium also includes support for DNS Sinkholes (similar to how I use my Pi-Hole) and Block List URLs. It'll automatically download block lists daily and block ads.

Technitium is a lovely .NET Core based DNS Server

It's also educational to try running your own DNS server and it's fun to read the code! The code for Technitium's DNS Server is up at https://github.com/TechnitiumSoftware/DnsServer and is super interesting from a networking perspective, but also from an C# perspective. It's a very interesting example of some .NET Core code at a very low level and I'm thrilled that it works on every operating system.

There's even bash scripts for setting Technitium up on your RaspberryPi or Ubuntu to make it easy. If you are using Windows and don't care about .NET Core you can use the .NET that's included with Windows and Technitum has a Tray app and Installer as well.

Some of the code isn't "idiomatic" C#/.NET Core but it's interesting to read about. The main DnsWebService.cs is pretty intense as it doesn't use any ASP.NET Core routing or primitives. It's a complete webserver written using only System.Net and its own support libraries, along with some of the lower-level Newtonsoft.Json libraries.

The main DnsServer is also quite low level and very performant. It lives in DnsServer.cs. It opens up n sockets (depending on how many ports you bind to) and starts accepting connections here. DNS Datagrams start getting parsed here, right off the stream. The supporting libraries and networking helper code lives over at https://github.com/TechnitiumSoftware/TechnitiumLibrary which is a wealth of interesting and useful code covering BitTorrent, Mail, and Firewall management. There's a ton of OO representations of networking concepts, and all the DNS records are parsed manually.

Technitium has a DNS Server, client, Mac Address Changer, and open source instant messenger. The developer is extremely prolific. They even host a version of "Get HTTPS for free" that works with Windows and makes getting Let's Encrypt certificates super easy.

Anyway, I've been enjoying exploring DNS again and reminding myself not only that it still works great (since I learned about DNS from sniffing packets in networking class) and it's been updated and improved with caches, DNSSEC, DNS over HTTP and more in the years following.

Here I've set my IPv4 DNS to 127.0.0.1 and my IPv6 DNS to ::1, then I run NSLookup and try some domain lookups.

Looking up domains at the command line with nslookup

Again, to be clear, the local DNS server took these lookups and then forwarded them upstream to another server. However, you have the choice for your upstream lookups to be done over whatever protocols you want, you can use Google, OpenDNS, Quad9 (with DNSSEC or without), and on and on.

Are you running your own DNS Server?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Your computer is not a black box - Understanding Processes and Ports on Windows by exploring

April 16, '19 Comments [16] Posted in Tools
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TCPViewI did a blog post many years ago reminding folks that The Internet is not a Black Box. Virtually nothing is hidden from you. The same is true for your computer, whether it runs Linux, Mac, or Windows.

Here's something that happened today at lunch. I was testing a local DNS Server (more on this on Thursday) and I started it up...and it didn't work.

In order to test a DNS server on Windows, you can go to the command line and run "nslookup" then use the command "server 1.1.1.1" where 1.1.1.1 is the DNS server you'd like to try out. Go ahead and try it now. Run cmd.exe or powershell.exe and then run "nslookup" and then type any domain name. You should get an IP address.

Given that I was trying to run a DNS Server on localhost:53 (Port 53 is where DNS usually hangs out, just like Port 80 is where Web Servers (HTTP) hang out and 443 is where Secured Web Servers (HTTPS) usually are) I should be able to do this. I'm trying to send DNS requests to localhost:53

C:\Users\scott> nslookup
Default Server: pihole
Address: 192.168.151.6

> server 127.0.0.1
Default Server: localhost
Address: 127.0.0.1

> hanselman.com
Server: localhost
Address: 127.0.0.1

*** localhost can't find hanselman.com: No response from server
> hanselman.com

Weird, that didn't work. Let me try a DNS Server I know works like Google's 8.8.8.8 public DNS

> server 8.8.8.8
Default Server: google-public-dns-a.google.com
Address: 8.8.8.8

> hanselman.com
Server: google-public-dns-a.google.com
Address: 8.8.8.8

Non-authoritative answer:
Name: hanselman.com
Address: 206.72.120.92

Ok, it seems my local DNS isn't listening on point 53. Checking the logs of the Technitium local DNS server shows this:

[2019-04-15 23:26:31 UTC] [0.0.0.0:53] [UDP] System.Net.Sockets.SocketException (10048): Only one usage of each socket address (protocol/network address/port) is normally permitted
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName)
at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Bind(EndPoint localEP)
at DnsServerCore.DnsServer.Start() in Z:\Technitium\Projects\DnsServer\DnsServerCore\DnsServer.cs:line 1234
[2019-04-15 23:26:31 UTC] [0.0.0.0:53] [TCP] DNS Server was bound successfully.
[2019-04-15 23:26:31 UTC] [[::]:53] [UDP] DNS Server was bound successfully.
[2019-04-15 23:26:31 UTC] [[::]:53] [TCP] DNS Server was bound successfully.

The DNS Server's process is trying to bind to TCP:53 and UDP:53 using IPv4 (expressed as "all local network adapters" with 0.0.0.0:53) and then TCP:53 and UDP:53 using IPv6 (expressed as localhost using [::]:53) but it seems like the UDP binding to port 53 on IPv4 failed. Weird.

Someone else is listening in on Port 53 localhost via IPv4.

That's weird. How can we find out what ports are open locally?

I can run "netstat" and ask Windows for a list of all TCP/IP connections and the processes that are listening on which ports. I'll also PIPE the results to "clip" which will put it in the clipboard automatically. Then I can look at it in a text editor (or I could pipe it through find or findstr).

You can run netstat --help to get the right arguments. I've asked it to tell me the process IDs and all the details it can.

Active Connections
Proto Local Address State PID

TCP 0.0.0.0:53 LISTENING 27456
[dotnet.exe]

UDP 0.0.0.0:53 LISTENING 11128
[svchost.exe]

TCP [::]:53 *:* 27456
[dotnet.exe]

UDP [::]:53 *:* 27456
[dotnet.exe]

Hm, a service is already listening on port 53. I'm running Windows 10, not a Server so it's odd there's already a DNS listener on port 53.

I wonder what service is it?

I can check the Services Tab of the Task Manager and sort by PID. Or can I run "tasklist" and ask directly.

C:\WINDOWS\system32>tasklist /svc /fi "pid eq 11128"

Image Name PID Services
========================= ======== ============================================
svchost.exe 11128 SharedAccess

That's Internet Connection Sharing, and it's used by Docker and other apps for NAT translation and routing. I can shut it down with the sc (service control) or with "net stop."

C:\WINDOWS\system32>net stop sharedaccess
The Internet Connection Sharing (ICS) service is stopping.
The Internet Connection Sharing (ICS) service was stopped successfully.

Now I can start my DNS Server again (it's written in .NET Core) and I can see with tcpview.exe that it's listening on all appropriate ports.

TCPView showing everything on Port 53

In conclusion, it's a good reminder to refresh yourself on the basics of IPv4, IPv6, how processes talk to/allocate ports, what Process IDs (PIDs) are, and their relationships. Much of this is taught in computer science university courses but if you're self taught or not doing low level work every day it's easy to forget.

Virtually nothing on your computer is hidden from you!


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Blocking ads before they enter your house at the DNS level with pi-hole and a cheap Raspberry Pi

April 11, '19 Comments [15] Posted in Hardware | Open Source
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image

Lots of folks ask me about Raspberry Pis. How many I have, what I use them for. At last count there's at least 22 Raspberry Pis in use in our house.

A Pi-hole is a Raspbery Pi appliance that takes the form of an DNS blocker at the network level. You image a Pi, set up your network to use that Pi as a DNS server and maybe white-list a few sites when things don't work.

I was initially skeptical, but I'm giving it a try. It doesn't process all network traffic, it's a DNS hop on the way out that intercepts DNS requests for known problematic sites and serves back nothing.

Installation is trivial if you just run unread and untrusted code from the 'net ;)

curl -sSL https://install.pi-hole.net | bash

Otherwise, follow their instructions and download the installer, study it, and run it.

I put my pi-hole installation on the metal, but there's also a very nice Docker Pi-hole setup if you prefer that. You can even go further, if, like me, you have Synology NAS which can also run Docker, which can in turn run a Pi-hole.

Within the admin interface you can tail the logs for the entire network, which is also amazing to see. You think you know what's talking to the internet from your house - you don't. Everything is logged and listed. After installing the Pi-hole roughly 18% of the DNS queries heading out of my house were blocked. At one point over 23% were blocked. Oy.

NOTE: If you're using an Amplifi HD or any "clever" router, you'll want to change the setting "Bypass DNS cache" otherwise the Amplifi will still remain the DNS lookup of choice on your network. This setting will also confuse the Pi-hole and you'll end up with just one "client" of the Pi-hole - the router itself.

For me it's less about advertising - especially on small blogs or news sites I want to support - it's about just obnoxious tracking cookies and JavaScript. I'm going to keep using Pi-hole for a few months and see how it goes. Do be aware that some things WILL break. Could be a kid's iPhone free-to-play game that won't work unless it can download an add, could be your company's VPN. You'll need to log into http://pi.hole/admin (make sure you save your password when you first install, and you can only change it at the SSH command line with "pihole -a -p") and sometimes disable it for a few minutes to test, then whitelist certain domains. I suspect after a few weeks I'll have it nicely dialed in.


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.