I have a simple RPi + RAK831 using a Chinese antenna all mounted on my TV antenna pole in the east of Ireland. The climate here is “temperate” so temperature ranges little by comparison to continental Europe for example, maybe -6 to 25C max range in the main. Right now I can see that the Pi’s CPU is at 30.4C. It is a rainy climate so I think skill in weatherproofing will be more important than temperature tolerance of the concentrator board.
The setup uses PoE injected at 19Vdc beside a small switch in my loft then regulated to 5Vdc beside the gateway. Everything is housed in a IP67 plastic box which should have enough volume and surface area not to overheat in our summer. So far using @kersing’s uper easy to setup packet forwarder (resin.io) with 100% reliability and a great console to monitor/manage the gateway.
Thanks @GryKyo. A fantastic post on your Gateway too. It sounds like you have had little problems once the Gateway has been installed, which is great to hear.
It does highlight the differences between climates though, here in Perth Australia we regularly hit 40C for days at a time during the Summer so I had better have the internal temperature monitored, fans installed and perhaps a max temp shutoff function!
OK, so once again I declare that I am a mech engineer, not a programmer but you could run a small python or similar on your linux box, I guess a Pi.
From command line:
/opt/vc/bin/vcgencmd measure_temp
will return your Pi’s CPU temperature which can be used to operate a fan or even a stand alone fan/temp controller in the installation. Only issue with this is remoteness and no closed-loop I guess. I have some projects which use cURL to push messages via Pushbullet to mobile devices and Chrome for alarms and warnings, very handy for remote devices.
With regard to the packet forwarder it has a live log and a SSH terminal so very suitable for remote control/monitor of your gateway and seems very robust in the short while I am using it.
This is a photo of the inside of the antenna (RP-SMA) included with my RAK831 (868MHz) board.
The antenna rattled when I picked it up. I opened it to see what was wrong and found that the coil had come loose, which I was able to fix.
Recent versions of this case have light pipes on both sides of the micro-SD slot so they are suitable for both RPi 2 and RPi 3. The brochure shows the older RPi 2 case which has light pipes for RPi 2 only (RPi 3 does fit in the older version but you would not see the LEDs).
In a simple test with a node about 2m distance from the gateway (node with same above antenna): RSSI jumped from -45 to -25 and SNR stayed similar around 9 to 10. (Have not done any further testing.)
The included whip antenna (rated by RAKWireless as 1GHz) does not perform very well in the comparison. Replacing it with a better antenna (like the above) will get better results from the gateway.
_(I replaced the RP-SMA connector on the RAK831 with SMA so it doesn’t need a converter for SMA antenna and prevents (minor) converter losses.)
Push button on GPIO17 to be able to shutdown PI Locally
FTDI connector to be able to take hand on PI console when in enclosure (lost network or whatever, no more need to get all off the enclosure and connect HDMI cable to see what’s going on)
Footprint for excellent Murata OKI-78SR-5 DC/DC 5V
Footprint for RASK831 concentrator (main goal) with pressfit connector for solderless PI Zero
I2C connectors to be able to add internal/external sensors such as BME280, SI7021 or HTU21D or excellent 2.4" OLED
Power with terminal block press fit
3 visual WS2812B Led (wifi and network state, packet state, …)
2 versions, the other is for outdoor enclosure even smaller
Currently writing documentation, monitoring scripts, RO filesystem to add robustness and even a procedure to have full lorawan server installed for local use
Also new 1.3 revision on the go to be able to put RAK831 on the other side of this PCB so we can see RAK Led (and fix silk error of RAK831 pinout)
Mounted this one in a hurry for a customer, works fine, but RAK831 is becoming hot in enclosure, need to check that point
As a fan of small OpenWrt/LEDE Linux thingies, I built a RAK831 based gateway based on Omega2S and created a LEDE build for it.
If anyone is interested:
here’s the github project with README explaining how to build the LEDE based TTN-gateway firmware from scratch. The firmware is not very elaborate yet, but it works out of the box registering a “legacy forwarder” based gateway with a EUI based on the Omega’s MAC address.
Here’s a PCB I had fabbed at oshpark which hosts a Omega2S, a ethernet jack and power regulators to run the entire GW via PPoE (network and power over the ethernet cable). It fits together with the RAK831 into a watertight IP65 case from Hammond (1554EGY).
It looks like you are using the antenna shipped with the RAK board. If so, I suggest you look for another one with better performance. If you want to use a whip antenna, if I’m not mistaken PyCom uses RP-SMA antennas for the LoPy. (@jmarcelino might be able to confirm)
Thanks for the hint - yes, in a first step I am using the antenna that came with the RAK, but I already saw posts in this thread saying there’s room for optimisation…
I’m a newbie regarding LoRA and antennas, much to learn here… My experience is with building small LEDE-based thingies, so I thought I’d start with that, making a HW/SW platform first. I very much like the way LEDE can reproducibly generate a complete TTN GW Linux firmware into a 6M image by just typing make on the command line (almost)
The cable you see on the photo is a very bad ultra-cheap cable (that violates every possible ethernet cable specs) I used for first tests, because it is so flat that it goes through the sealing of the case. In the meantime a proper ethernet cable goes through a sealed grommet in the case.
About temperature - the max power both Omega2 and RAK consume together is about 2W, the average usually less than that. That should be easy to dissipate through the plastic box. The max operating temperature of the RAK is 85°C. We get 35°C max here in Zürich, so I think there’s enough margin even in direct sunlight in summer (for a white box with free air circulation around it).
Very nice!
