Got back from a short field trip and site survey to find a couple of these beauties I had requested from @edwin and the Dragino team waiting for me:
LDDS75 Ultrasonic Distance Sensors
Got one quickly registered into TTN yesterday…well it would have been quick if I hadn’t mis-typed a couple of characters from Dev-EUI/App-EUI then lost time trying to debug Dho!
Loaded the stock decoder and could see distance & battery data in App console:
A short while later I had it running under a Cayenne Integration and showing data on a standard dashboard. Left it running overnight hanging off edge of desk…great news the flat line shows the earth didnt move relative to the desk last night. Tried in a couple of places outside today before loading over the test rainwater butt outside the office, where it has been stable on 20min updates since.
Tommorrow will start the butt on a slow drain down (a few hours) and see how well it tracks reducing water level (increasing distance) until empty as a quick calibration check. The 2nd unit will be deployed at the weekend on long term test on a small stream feeding the River Thames nearby ready to check for summer thunderstorm driven flooding, leaf blockages over the Fall and the Winter general water level increases…
1st impressions very good, easy to set up and will report back on long term reliability/battery consumption etc… may have to get a few more of these…
I had this idea already for a long time, collected the parts some time ago and yesterday night I came to the point where I actually did it: I started replacing the existing battery holder of a The Things Node for a LiPo and a DIY Qi wireless charger:
The Qi wireless charger is connected to an Adafruit PowerBoost 500 Charger (https://www.adafruit.com/product/1944) that will power the Things Node. The Things node is internally equipped with a 3,3 volt LDO.
I now have to see if I can add some signals to the microprocessor to the Thing Node to monitor the behaviour of the Qi wireless charged battery.
If anyone has any documentation on the Qi wireless charger like this one, that would be helpful.
I have read that a battery could be connected to it but I have not found directives nor schematics to do so. It would save me the Powerboost 500 and space for a bigger LiPo battery.
Manufacturers, please provide QR codes! (Especially for gateways with sequential EUIs, where a typo may lock the EUI of a future buyer’s gateway if it has been erroneously registered and deleted.)
2 new temp sensors from Maxim. I2C version standby current ~1/5th the 1-wire may be good for v.low power nodes. Both potentially good for easy build accurate nodes?
Found this little ATmega328P + RFM95W combo on AliExpress …
Small box of 5, separate MCU board + radio chips cost £22.27 aka £5.44 each. The vendor sells a number of combinations for regional frequencies or using RFM69.
The PCB doesn’t have a link for DIO1 trace, hence the yellow wire. Took about 5 minutes to solder and three minutes to setup ABP & download using Classic LMIC and see uplinks.
Tomorrow I’m make another, add DHT11’s & a 7805 Vreg and wire them to both cars that are suffering badly from damp at present - may as well get some hard data on the problem.
To students and beginners, these modules are very entry level, the principal problem is the shortage of memory - they are cheap, good for ‘disposable’ devices or only requiring one or two simple sensors. They are not a good match for those wishing to warp time & space by rushing to an end result.
With the launch of the new Raspberry Pi 400 Keyboard kit ( The LIBRARY basement part 12 ) I was scratching head thinking how to best use my new acquisitions.
Then it struck me - add 40way external cable, break out connector bd &/or interposer board such as one of those from Charles/Ch2i used previously with RPi0W’s, drop in a SX13xx concentrator card such as those from @kenyu and our friends at @rak such as this one contributed by friend of the TTN @jmarcelino and Bingo!
An integrated GW development kit - just need to break out the soldering iron and smd reflow kit
Guess what me and the kids will be playing with over Xmas & New Year?!
Dho!
- just need to break out the soldering iron and smd reflow kit 
