(Continued from Part 2.)
Charging
In regards to charging, most Meshtastic devices have a built-in USB-C port for charging the internal battery (except for the T1000-E mentioned above). The USB-C port can also be used to connect to the device to a computer for upgrading the firmware or managing the device via a web browser.
Compact Comms
Above is a picture of several Meshtastic devices to give you an idea of their sizes:
From right to left, the devices are:
- Seeed Studio SenseCAP Card Tracker T1000-E ($40, assembled device)
- nRF52840 microprocessor
- LR1110 LoRa radio
- 700mAh
- Mediatek AG3335 GPS module
- Heltec T114 ($42-$50, complete kit)
- nRF52840 microprocessor
- SX1262 LoRa radio
- 800mAh battery
- L76K GNSS GPS (optional)
- Meshnology N33 ($32, complete kit)
- Heltec WiFi LoRa 32 (V3) board
- ESP32-S3FN8 microprocessor
- SX1262 LoRa radio
- 3000mAh Battery
- No built in GPS
- Heltec WiFi LoRa 32 (V3) board
- Meshnology N30 ($27, complete kit)
- Heltec WiFi LoRa 32 (V3) board
- ESP32-S3FN8 microprocessor
- SX1262 LoRa radio
- 1100mAh Battery
- No built in GPS
- Heltec WiFi LoRa 32 (V3) board
- Elecrow ThinkNode M1 ($54, assembled device)
- nRF52840 microprocessor
- SX1262 LoRa radio
- 1200mAh battery
- GPS (not sure which GPS module)
IMPORTANT: If you choose to buy a kit and assemble it yourself, make absolutely sure that you connect the antenna to the board BEFORE connecting the battery. Plugging in the battery will immediately cause the device to boot up, and like any radio transmitter you can damage the finals if it tries to transmit without an antenna attached.
Planning
If you’re going to incorporate radios into your preparations you should obviously do some planning – create a band plan, write down comm procedures, create code words/phrases, etc. The same holds true for using a Meshtastic network – you should plan on how you want to deploy and use the devices before you really need them. If you’re like me and you can’t wait to open up and try out your new device as soon as it shows up, go ahead and do so – it’s a great way to learn how the device works and get comfortable with it. However, you should also put a documented plan in place to make sure you can implement an effective Meshtastic network when a disaster hits.
First, you should understand how much range you can get from Meshtastic devices in your area of operations. There’s a Meshtastic Site Planner web site available that can provide pretty good range estimates based on your location, terrain and other factors. Go to https://site.meshtastic.org/ and scroll/zoom the map to find your location. Click the blue ‘Set with map’ button in the right-hand frame, then click on your location on the map – a red pin will show up on the map. Note that the site name will be created automatically in the right frame using two random words, but you can set it to anything you want.
You can also change the frequency and a lot of other settings in the right frame, which allows you to see what frequencies may work better in your area. Once you’ve set your location, click on the green ‘Run simulation’ on the bottom of the right frame and the system will generate a maps showing estimates of the Meshtastic signal strength around your selected location. Here’s an example of a site planning map centered around an area in Pittsfield in southeast New Hampshire:
The lighter the color, the stronger the signal. Notice that the location selected (the yellow area in the lower right) is down slope on the northwest side of a large hill, so much of the signal to the south and east is blocked. There are also scatterings of decent signal reception over 10 miles away. You can try different frequencies and different locations to better understand what kind of range you can get. This can also be useful to help you figure out where you may want to install a Meshtastic repeater in order to increase your range. In the above example if you were to install a repeater on top of the hill you could significantly extend reception to the south and east.
Once you understand what your site will look like you should consider how many and what types of Meshtastic devices you’ll need. As I mentioned earlier the Seeed Studio SenseCAP Card Tracker T1000-E is currently an inexpensive out-of-the-box device; it has pretty good range and battery life and supports GPS location data, so it makes a good choice for the majority of the users that will be primarily staying in the local area.
If you want something with WiFi, no GPS and a replaceable antenna as a ‘base’ device on your home network and you aren’t adverse to some basic assembly the Meshnology N33 package (make sure you select the ‘Board+Battery+Case’ option) which uses a Heltec ESP32 board is an inexpensive option.
Having a lot of Meshtastic devices on a single network can get confusing, so you should create a device naming convention. Each device has two user names – a long one and a short one. The long name can be a maximum of 39 characters and can consist of pretty much any printable character like letters, numbers and special characters. I recommend that you assign each device to a single user and use that person’s full name as the long name. You can pre-pend a qualifier if you have a scenario where one person could potentially use multiple devices.
For example, if you have several separate devices that are used exclusively by people who are out on patrol to create their own mobile mesh network you can use something like ‘Patrol1 – John Doe’ to distinguish the device from John Doe’s home device. Each patrol device can be easily re-configured with the correct long name right before the patrol leaves.
Short names are limited to four characters so they can be a little bit tougher to assign. I recommend you take it on a case-by-case basis to come up with the best possible short name. For example, ‘John Doe’ could be ‘JODO’, and ‘Jane Doe’ could be ‘JNDO’. For a set of shared devices like the patrol example, you should consider using like ‘PTL1’, ‘PTL2’, etc. for the short name, and make sure the prepended text for the long name is correspondingly set – e.g. the long name for the device with ‘PTL1’ for a short name is prepended with ‘Patrol1’.
Regardless of what you name the devices I recommend that you attach a label to the outside of each one with the long and short names so they don’t get easily confused. I use a label maker to print out each name, stick them on the device and cover them with a small piece of clear Gorilla tape to protect them. Note that some of these devices are pretty small, so you may have to write the names in small print with a fine permanent marker on a small piece of white medical tape and cover it with clear Gorilla tape.
The next thing you will want to plan are your ‘channels’ (not to be confused with radio frequency channels). You can think of channels as sort of a chat room with restricted access – only devices that have the channel’s encryption key can read and send messages in that channel. Note that any Meshtastic device on your mesh network that’s not part of a channel can still pass messages to other nodes – it just can’t read them. Channels can be useful for grouping together people that need to share specific information that may not be of use to others. For example, you can have a ‘Security’ channel for your security team, a ‘Farming’ channel for people responsible for growing food, a ‘Kids’ channel (although you’ll probably want to have an adult monitor that one), etc.
If you are able to establish Meshtastic communications with another group, nearby town, etc. you can create a separate channel just for inter-group communications. I recommend you have at least one common channel named something like ‘AllHands’ that everyone in your group has access to so you can send emergency alerts, call everyone to dinner, etc. Note that each Meshtastic device can participate in up to 8 separate channels – 1 Primary channel (required) and up to 7 secondary channels. I generally recommend using the Primary channel as the all-hands common channel. Note that channel names are case sensitive, so ‘Security’ and ‘SECURITY’ are two different channels.
Something else you may want to consider – since you’re sending short text messages you can save a lot of typing by coming up with a set of standard acronyms for common terms and phrases. For example you can use ‘RTB’ to mean return to base, and if it has an exclamation mark (RTB!) it means hurry up. If you or your group are already frequent users of SMS messaging on your cell phones you’re probably familiar with many of the common acronyms in use, so you may want to start with those so you don’t have to re-invent the wheel.
(To be continued tomorrow, in Part 4.)
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