the it blog.
Many 868MHz antennas from Aliexpress are not really designed for 868MHz but sold as such.
Therefore I would like to share two antennas with you, which are designed for 868MHz.
‘Big’ 868MHz antenna from Aliexpress
VSWR 1.19 at 868MHz, tested with N1201SA.
Small 868MHz antenna from Aliexpress
VSWR 1.20 at 868MHz, tested with N1201SA.
Many makers are using breakout boards for their projects, they are easy to use, as additional required components are already included on them, like pullup resistors and capacitors.
But, sometimes there are also components soldered on those breakouts which are not required for a project.
I’m aware of two different BME280 breakouts from China, a 6-pin one and a 4-pin one.
The 6-pin breakout only consist of a few parts, the BME280 sensor, some capacitors and resistors.
The 4-pin breakout consists of a few parts more, the BME280 sensor, some capacitors and resistors, a voltage regulator and a to me unknown chip.
Low power projects are often run from battery, there the amount of power over time is limited. Here the standby/sleep current is the most important one, as the sensor is most of the time doing nothing.
The sensor was put into ‘forced mode’ for all measurements in this post and was powered from a 3.3V source. For the measurements a Siglent SDS 1102CML+ was used combined with an uCurrent GOLD.
Stock 4-pin breakout: 7.66uA
Stock 6-pin breakout: 0.173uA
So you can clearly see, that the 6-pin breakout is better suited for low power applications as it uses 44 times less power, but you have to take care to supply the correct voltage, according to the datasheet:
‘Supply voltage VDD main supply voltage range: 1.71 V to 3.6 V’
But what happens if we do remove the voltage regulator on the 4-pin breakout?
4-pin breakout without regulator: 0.179uA
If the regulator is removed, the result is nearly the same as with the 6-pin breakout.
So you can either use the 6-Pin version or the 4-Pin version and remove the regulator and solder in a piece of wire.
Interested to help to expand the coverage of thethingsnetwork.org project, short TTN? There are many gateway you can use, for example you can build your own TTN gateway using a RPI and a IC880a or RAK831 concentrator board.
Both solutions are priced at about CHF 150-200, depending on where you order the hardware, what kind of RPI you’re using and if you have to pay import duties or not.
But of course, you need some time to get up and running. Wiring, software and so on. Check out the TTN-ZH github page for a smooth start.
If you don’t have the time, you can buy a commercial product, the Laird RG186 gateway.
Included accessoires:
After you got it, simply unpackage it and plug in power and a network cable (it also has WiFi built in, but haven’t used it). Open your browser and connect to the DHCP IP address it got and log in to the device.
Default login credentials:
Username: sentrius
Password: RG1xx
Go to the ‘LoRa’ tab, and select a preset for The Things Network.
If you use ‘The Things Network Legacy EU’ you can simply apply the preset and copy the EUI displayed on the left side. Then go to https://console.thethingsnetwork.org/gateways and register the gateway. Please note to activate the checkbox ‘I’m using the legacy packet forwarder’ when registering the gateway.
If you use ‘The Things Network EU’ it is best, to go first to https://console.thethingsnetwork.org/gateways and register a new gateway, as the gateway ID can be choosen by you! After creating the gateway, copy the ‘Gateway Key’ and go the the RG186 webinterface. Apply in the ‘LoRa’ tab the preset ‘The Things Network EU’ and go then to the subtab ‘Forwarder’. Enter your ‘Gateway ID’ and the ‘Gateway Key’.
In both cases the gateway should now show up as ‘connected’, once on the RG186 dashboard and also in the TTN console.
For more detailed set-up instructions and technical specifications, please check out the official Laird RG1xx product page.