This article reviews the Dragino LG02 LoRa ‘gateway’.
Above is a pic of the supplied device, and notably it is supplied without the external WiFi antenna shown in the manufacturer’s literature and seller’s web shop.
Above is a close up of the case with the plastic plug removed from the ANT-3 hole, there is not connector, the device does not have provision to install the external WiFi antenna and presumably has an internal antenna though we might expect that has reduced range. Continue reading Dragino LG02 review
This article documents a project with the Espressif ESP8266.
This project is based on ESP8266 IoT DHT22 temperature and humidity – evolution 3, but uses the Bosch BME280 temperature, humidity and pressure sensor. The BME280 has been around for a couple of years, but recently, modules using the chip have become available on eBay for a couple of dollars.
The objective is a module that will take periodic temperature, humidity atmospheric pressure (barometer) measurements, and in this evolution publish them using a RESTful API.
The example platform used in this article is a Wemos D1Pro. In this case, the D1Pro is configured for an external antenna, and a modification is made to the board to add a 1N34A diode for the deep sleep reset circuit (NodeMCU devkit V1 deep sleep). A right angle header on the top of the board (as seen) and another on the underside on the opposite edge to get GND, +3.3, D3 and D4 for the BME280 sensor. There is less than $25 in parts in the pic above. Continue reading ESP8266 IoT BME280 temperature, humidity and pressure
Several of my IoT projects use WiFi, and its range is quite limited, too short to be practical for some projects.
There are several alternatives, but the emerging LoRaWAN concept looks interesting and is worth a visit. LoRaWAN is capable of up to 20km range under ideal conditions, km range should be reliable in most cases.
The first trial is to adapt an existing project functional requirement to LoRaWAN connectivity.
Above is a block diagram of the working trial. Continue reading IoT – exploration of LoRaWAN – part 1
I bought a cheap Pulsar V233-0060 on eBay, you know, one that was advertised as “was working 10 years ago, just needs a battery”.
Of course if that was true, the seller would fit the battery and describe it as working and get lots more money for it.
Pulsar is one of Seiko’s brands, and this movement appears in Seiko branded watches.
Anyway, as it inevitably the case, it did not work.
External examination revealed that with a good battery, the 32kHz crystal was running, but no motor pulses. A further test with external turbo magnetic drive showed the motion works was working… so now pointing to a coil problem.
Continue reading Pulsar V233-0060 stripped down
I bought a little 4-20mA source on eBay for under $10.
The device has a backlit LCD display, and a rotary encoder with steps of 0.05mA (or 0.3125% of 16mA). The current setting can be set as power on default by pressing the knob. It is supplied with a 250Ω resistor which could be used as a load resistor in projects delivering 500mV FSD.
Continue reading Inexpensive 4-20mA source – review
The 4-20mA loop used for the water sensor needs a source of 24VDC. This is obtained from the battery (3.6-4.3V) using a DC-DC boost converter which runs only when a measurement is made.
This article discusses related issues. Continue reading IoT water tank telemetry project – part 4
It seems that almost all small DC-DC converter modules listed on eBay with LM2577 in the headline actually use the Chinese XL6009 chip which they may or may not state “replaces LM2577”.
But… is it a replacement? Continue reading XL6009 DC-DC converter chip issue
The project continues, albeit slowly.
Some inexpensive DC-DC boost converters have been very slow from China, though multiply source, they have not yet arrived.
An older module which was on hand has enabled progress of reliability and battery trials.
Above is the current prototype. The module on the white plug in cable is a 4-20mA simulator set to 20mA for maximum drain during battery trials. The module at upper right of the pic is a TP4056 batter charger and 1S protection board for the 2000mAh LiPo. The PV array (partially obscured) is capable of 80mA of charge current in full sunlight. The prototype includes a red LED drawing 1mA, an additional 24mAh load per day. Continue reading IoT water tank telemetry project – part 3
I have a ceiling fan which has poor balance and is quite annoying on its high speed.
To solve the problem, I attached a flight controller board which I had on hand for this sort of purpose to the stationary spindle extension, and I have the associated configuration software installed for flying machines
Above, the OmnibusF4 v1 flight controller. Not a good flight controller for flying machines because of the silly pinout, but cheap (for that reason), about $20 on eBay. The flight controller contains a 3 axis gyro and accelerometer, the latter will be used here. Continue reading Balancing a ceiling fan
This article is documentation of a capacity test of 5 x Hobbyking 2500mAh 18650 LiIon cells (9210000181-0).
The cells were purchased on 26/02/2018 (~$7 + shipping) and received at about 30% charge. They were each charged in a XTAR VC2 Plus charger at 0.5A until charged.
The cells are 65mm long, and do not claim to contain protection modules which are prudent in some applications.
Each cell was then discharged at 1A (0.4C) to 2.8V, the discharge was captured.
Continue reading Hobbyking 2500mAh 18650 LiIon cells (9210000181-0) initial capacity test