Tag Archives: raspberry pi

Mmmm… Pi….

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If you’ve talked to me at all about computers, you know that I love these things. Or if you read my previous post about DV hotspots in Amateur Radio, you must have noticed that I mentioned a device called a Raspberry Pi. In the post I discussed the Pi Zero briefly. Today I just want to quickly go over what a Raspberry Pi is, and why you should have at least one if you want to play around with any technological concepts.

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Pictured on the left is a model B+ of the original Raspberry Pi board, and on the right is the more recent Raspberry Pi 3 B board.

The Raspberry Pi is a credit card sized computer. It has a handful of ports – 4 USB, 1 Ethernet, 3.5mm Stereo, HDMI, Micro USB (for power), Micro SD card slot for storage, 2 ribbon cable slots on the board (1 for camera, and 1 for a display), as well as a 20 pin GPIO.  They upgrade the memory on them between releases, and the Pi 3 is a lot more powerful than the original Pi was for sure, in addition they now have built in WiFi and Bluetooth where as before you had to get a USB device to have the capability. In addition, via the ribbon cable port you are able to convert it into the functioning touchscreen computer below.

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What purpose does this serve really though? Why should you want one of these? There are a few things that can be done with these for sure – I have primarily used them in radio applications for running hotspots, and logging, however I am in the process of building a media server off of one as well (been a long process, just need to pull the trigger on some storage, and it’s ready), which will allow me to have the entirety of my music, photos, and movies stored on it, and will make it accessible from anywhere. Pretty neat, right? All off of a board that’s the size of a credit card. You can tie them in for home automation, security systems via the camera port, media center boxes, and any hardware tinkering you want to do, you can fiddle around with the GPIO – check out the people that have built robots and drones with these, they’re really cool. They’re a sandbox for technological play – pretty much any concept that you have you can probably fill in with one of these.

In addition to the Pi, there is the Pi Zero that I mentioned in a prior post. That is a board only slightly larger than the size of a stick of gum. It has 2 micro USB ports, one micro HDMI, a ribbon cable port for a camera, and an SD card slot. That is it. I don’t have any photos, but you can check them out here. This I haven’t really played around with too much, but it’s a slimmed down, bare bones version of the Pi, meant for you to be able to play around with for single uses.

What’s Next? – How about a little digital talk?

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Field day is but a week and a half away at this point, and my radio is setup as one of the main stations, and as I live in a smaller apartment space, setting up, and breaking down is a process the way I have everything wound up, so I will not be on the air for another couple of weeks… from home at least, I always have the mobile. And I guess I should specify on the air for sideband – I do operate the currently dominant digital protocols as well, so I’ll be on D-Star, Fusion, and DMR.

On the note of digital, why don’t we discuss a little device that has become the be-all, end-all of digital hotspots, the ZumSpot. For those of you that don’t know, the digital protocols that most all major radio manufacturers produce at least one radio for now are pretty reliant on the internet when it comes to their extended features. Sure, you can talk D-Star, or DMR simplex, and you can use the repeaters locally if there are other people in your area with the ability to use them, but where’s the fun in that? With the infrastructure that’s out there, we can talk all around the world!

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I picked one of these little guys up in Dayton this year. It’s a small, single band (70cm) MMDVM (Multi-Mode Digital Voice Modem) board that you use in conjunction with a raspberry pi computer. It attaches right to the GPIO, you screw on an antenna to the SMA connector, and after setup of the software, you’re good to go! They’re powered simply via the Pi through the GPIO, so you have no additional power concerns. In the above photo I am powering it through a PowerFilm Solar phone charger. With this battery bank at a 50% charge or so when I plugged it in, I had around 7 hours of usage of the ZumSpot, only about 30 minutes of talk time, however the remainder was receive time. You can purchase it as a kit for $129.95 from HRO, that includes the hotspot, a raspberry pi zero, and a small SMA rubber duck antenna to attach to the board. I will warn you that this doesn’t come with a case, there is a case available for purchase, it’s a real pain to put together, but it works for sure, and I would highly recommend putting something on it so you don’t just have open circuit boards laying around.

It is the most all inclusive hotspot produced to date, it covers the big 3, as well as P25, and NXDN, with support for running cross modes if you can figure out how to set it up. I am no expert. By any means. It took me close to 12 hours of playing around with this to realize that when I changed my call, I never reconfigured by D-Star registration correctly. That was in December, it’s now May at this point – just goes to show how little I use the D-Plus reflectors. After I finally get all of this configured it works perfectly. I have been using it on and off, bringing it with me tethered to a cell phone for internet service, linked to the DCS006B reflector.

I’m not going to go through the details of setup here, I may make another post about that, however it’s straight forward. If you have any interest in these modes, this is one of the cheapest ways to get into it. If you feel like putting together a repeater to play with the mode, go for it, but if you just want something small, cheap, not needing tons of equipment that’s going to require a second mortgage to get running, you can get one of these boards, and the entry level radio for one of the modes – I’d suggest the Icom ID-31 for D-Star, the Yaesu FT-70 for Fusion, and the TYT MD-380 for DMR (only because of the users groups and assistance that can be given), and still get out for under $400 – especially if you catch the radio’s when there is a manufacturer rebate.

Definitely something I would recommend to anybody that is looking to play with digital voice modes locally as it is such a simple way to get in to it.