Sunday, January 31, 2016

Arduino DTMF Decoder and Relay Controller

Another Arduino project I've been working on is a DTMF decoder used to control a relay board. Using a ham radio receiver, I can switch lights, radios, computers...anything...on or off from miles away. Here's the video:


Here's the wiring diagram. And here's the Arduino code.

I'm using a Sainsmart 4 relay board, although pretty much any relay board would work. You'll also need a MT8870 DTMF decoder - these run about $2 on ebay. And of course, you'll need an Arduino Uno. Again, check out ebay for these as well. The total cost here should be less than $12 and you've got a fully functioning radio controlled DTMF relay controller!


Thursday, January 28, 2016

Web Based Repeater Power Controller

This week we installed a new Yaesu Fusion DR-1X repeater at a very nice site in Central Illinois. One of the things I'm a big fan of is controlling supply power via the web. This ability to remotely control the repeater is great - even if the controller goes belly up, you can turn the entire system off or just remotely power cycle it. I've used the Digital Loggers data center type power strips before, but they are a bit expensive - over $100. So for this site, I used the Iot Relay - Enclosed High-power Power Relay for Arduino, Raspberry Pi, PIC or Wifi, Relay Shield also from Digital Loggers. At under $20 from Amazon, it's a great deal. It's a relay connected to four outlets, enclosed in a very nice plastic case. Hooked to a Raspberry Pi, this little box provides me the ability to power cycle or turn off any equipment via the web. How do I get the from the web to the remote repeater site? Well through AREDN ham mesh software running on 5GHz equipment of course!

Since I had an extra Raspberry Pi on the shelf, this quick hack made for a fun project. I'm also going to add a temperature and humidity sensor so that we can monitor the environmental conditions in the repeater building. Here's a short 3 minute video I made explaining the code and the connections. Have fun! Put the Amateur back in Amateur Radio!


Tuesday, January 26, 2016

D-STAR VHF/UHF Handheld for $299.95

I'm happy to report I've been involved in adding three new hams to our ranks in the past two weeks. I had lunch with one today and we got to talking about radios. He wants to get on the local repeaters right away, and so we started talking about analog versus Fusion versus D-STAR. When we got to the topic of price, I was blown away to find out he had found brand new D-STAR ID-51 VHF/UHF handhelds for $299.95 shipped. It's a long way from a $20 Baofeng, but to have the ability to talk around the world on VHF or UHF for $299.95? That's a pretty good deal.

Monday, January 25, 2016

Internet access into ham radio mesh network

In my continuing work with the ham radio AREDN (amateur radio emergency data network) mesh software, I've come across the need to provide access from the internet to a host located across the mesh. Unfortunately,  the AREDN graphical interface doesn't provide a way to do this.

But don't despair! If you're capable of editing a file on a linux based platform, you can add your own firewall rules on the AREDN node that is connected to the internet to provide this access. On the AREDN mesh gateway you edit the /etc/firewall file and put in either a routing rule or a SNAT/DNAT rule. The difference is whether or not the gateway node will just pass the traffic through or if it will proxy (NAT) the traffic onto the mesh.

I'm working with the AREDN developers to add this functionality to the gui, and I'd expect that to come out later in 2016. In the meantime, if you're interested in making this work drop me an email and I'll send you some instructions! My callsign is KG9DW and I've got an arrl.net address.

Sunday, January 3, 2016

Winter update from KG9DW

Welcome to 2016! Lots of big projects are going on here at the radio ranch. My youngest is working on an arduino powered weather station that will be located at the FFA field plot along US51 north of Heyworth. We're going to get the data from the site using the AREDN ham radio mesh software. It's a real cool project, and my daughter is doing a great job with the programming.

I finally got all of my coax run into the shack in a decent fashion, and I've got coax switches in place to be able to toggle between the two hf rigs and the two hf antennas. My next antenna will either be an hf beam, or I'm putting up a sky loop. Or maybe another windom positioned north to south. Who knows!



I played with the Yaesu Wires-X software and an HRI-200 box this past week. I hooked it to a Motorola CDM-1550 mobile radio. I really like these Motorola radios - great receive, easy to interface, and just all around bullet-proof. These are the same radios I've used for two D-STAR repeaters...hard to beat. Anyway, I've got the Wires-X setup on a UHF simplex channel linked into the Central Illinois room. Wires achieves the same as a D-STAR reflector, just done a different way. I'm running Wires in analog mode, and so my analog audio is digitized at my computer and sent on to the server running the room. From there it goes to whoever else is joined into the room. If someone is running Wires in digital mode, the audio comes out digital. If you're running analog, it comes out analog. I'm not sure if I'm going to hook this into our Heyworth analog machine, or if I'm just going to keep it as a simple simplex node (a hotspot in D-STAR speak).


We've got a DR-1X repeater coming to Heyworth to replace the Kenwood TKR-820 the club has up on the elevator. The big benefit for us will be to replace the old Kenwood that sometimes has problems in warm weather, along with getting rid of a crazy long squelch crash. The new repeater arrives on Tuesday, and I'll let it burn in for a few weeks (or months depending on the weather) before it goes up on top of the elevator.

That's it for now...have a great year everyone!