The WORKBENCH part 3

No enclosure yet :roll_eyes:
So I left it on the floor in the garden shed…
Same temperature as outside, a bit less moisture (hopefully)

for sure

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LTH5200 series is a LoRa based temperature and humidity sensor.
Soon on the workbench for a review, the very first, hope to find the right ‘style’


Here it is…


Temperature dropped only to -3, but the LiFePO4 battery voltage has been stable throughout the night, no drop with the temperature.

I need to look more in details to the data, because I have 2 gaps in the graph. The device didn’t crash as the packet counter didn’t reset. It might be unrelated as I also have gaps with other nodes (e.g. the orange line) and this is very unusual…


select max(temperature),min(temperature),last(temperature) from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           max  min  last
----                           ---  ---  ----
2019-01-21T08:31:20.274882581Z 22.5 -2.8 -1.3


select max(voltage),min(voltage),last(voltage) from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           max  min  last
----                           ---  ---  ----
2019-01-21T08:35:21.574417311Z 3.28 3.27 3.27

Missing points:

select * from environ where dev_id = 'bulles-minilora-01' and time >= now()-24h

time                           analog_input counter data_rate dev_id             humidity pressure rssi snr   temperature voltage
----                           ------------ ------- --------- ------             -------- -------- ---- ---   ----------- -------
2019-01-21T22:21:28.504029864Z              2322    SF7BW125  bulles-minilora-01 80       1009.8   -84  9.25  -2.1        3.27
2019-01-21T22:31:36.201477425Z              2324    SF7BW125  bulles-minilora-01 79.5     1009.7   -84  8.25  -2.2        3.28
2019-01-22T06:17:32.845840515Z              2416    SF7BW125  bulles-minilora-01 77.5     1001     -83  9.25  -1.8        3.28
2019-01-22T06:37:48.487811162Z              2420    SF7BW125  bulles-minilora-01 77.5     1000.6   -83  7.75  -1.8        3.27

So I am missing 1 packet at 22:21Z and 3 at 06:17Z.
I don’t have gateway logs to cross check, but given the fact that frame counter was incremented, it looks like the node sent them but got lost…

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My test with LiFePO4 failed during the night. Temperature was -5 degrees Celsius. So this battery type is not better than Lion in these cold environments :frowning: Note that I enabled brownout detection on the MCU; it would have stayed alive longer if I had disabled that feature.

Strange – temperature in Brussels was a couple of degrees higher, but I don’t observe any voltage drop…

I did also place the sensor boxes on the cold soil in the garden outside.


I’d put off playing with these boards (Lora Node 1.0) for ages and after playing with one last night I am warming to them now, do we have a thread for them? if not can we create one and I will add some notes/comments,

PC 433Mhz/868MHZ/915MHZ lora module SX1278SX Module ATmega328P Wireless DIY Kit for Arduino pr…

This was on my workbench so I posted here :slight_smile:


Interesting to know your experience. A separate thread is good I think.

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A good chance to kill these is also the often ignored fact that these chemistry can/should not be charged below 0°C. There are many (solar) charging circuits out there which do not implement this.


I disabled the brownout detector and now the batteries work fine in the cold :slight_smile:


Fire!!! My NEW budget test rig caught fire and 18650’s went off like rockets.
Cause: overheating and I had not installed a BMS yet, was undercharging instead which clearly was not enough.
source: FB group DIY Powerwalls

That does not surprise me…

Too many people still have to understand that LiPo batteries are really dangerous and need to be handled with care.

I am not saying you can’t do it in a safe way, but a power wall is much more than just putting a bunch of cells together.

a bunch of OLD cells … :wink:


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‘job’ today … get that '2.2 TFT working and measure what’s the total consumption (sleep/no backlight)




Sparkfun info - voltage dividers and levelshifting

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That are great boards when you need more IO and memory. :ok_hand:

Have used them in various projects.




Product Introduction:
1.Driving Port Signal Voltage:3.6-24V
2.Output Port Voltage Port:3.6-30V
3.Jumper Cap Can Achieve Output Port Is High POtential Or Pull Down Output
4.Onboard 4-Channel 817 Are Independent:can achieve different voltage control at then same time

The input port is shared with GND;
The output ports are independent of each other;
Optocoupler output V and G will be connected after valid input signal.



  • A $500 wireless router
  • A $3 'pluggy boi

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