Arduino Arsing About

 A friend has a Sofar HYD 6000-ES hybrid PV inverter installed, and I was interested in The possible security implications of its nominal WiFi/Internet connection How to get the logging data directly into one's own software and bypass the "cloud" which is located in China! Security Issues In respect of the first point, this webpage has some interesting insights viz. the Access Point (AP) interface remains active even when you've configured it as a Station (STA) to access your home WiFi, including the following interfaces, according to the article: 53/UDP, DNS 80/TCP, HTTP 8899/TCP, Datalogger Info 48899/UDP, HF AT Interface Depressingly, the article shows how easy it is to hack the passwords from copies of the firmware :-/, so given the importance of the kit, it's probably good to take some remedial action. Possible actions: Access Point access: The configuration screens allow for the SSID to be hidden, which at least prevents casual detection/connection, althoug...

The visiting daughter seemed to be spending a long time in the shower, as the pump motor ran and ran... However, she then appeared downstairs, and suggested that there may be something wrong with it, as she'd turned it off and the motor was still running! Damn. With her spouse and the g-kids also staying, it could be a problem. First stop, press the "test" button on the in-circuit RCD to kill the power... View of pump, pointing to one of the two sensors I already realised that the pump turns on when the state of the water in the output lines changes, pressure, flow, whatever. Some Googling revealed that equivalent 3bar pumps are not cheap! So just buying one and replacing it myself was financially not the first option. So - repair? A photo of the inline switches revealed the text "HAMLIN 59600-444". Hamlin apparently make reed switches, and although I'd not really given much thought to how the pressure/flow switches might work, this seemed pretty reasonable....

The energy monitoring project is ongoing. Meanwhile, we're using the washing line lots because it's "summer" in the UK, which brings the perennial problem of retrieving said washing when it inevitably rains. Neither of us seem to notice when it starts, unless we're outside, standing in it. Hence the Rain Alert. Plan is Obtain water sensor panel and associated I2S adapter with LM393 voltage comparator Decide on MCU type (Arduino? No, NodeMCU with ESP8266!) Software config Generate MQTT alerts which can be monitored by NodeRed Calibrate sensitivity pot and software values Send alerts if it rains over Telegram to mobile phones, and hence FitBits for intimate reminder (!) Hardware packaging and power for externally resident device So far, I've got as far as 4 above. I was going to programme the ESP8266 myself, but it's just as easy to use the Tasmota software and configure that. It will send MQTT SENSOR messages with all the collected values as frequently as I...

Today I looked at connecting the CT - Current Transformer? This is a 2000 turn secondary, clipped around the 1 turn of the incoming house mains cable. It thus provides a maximum RMS current of 20mA, given a maximum house current of 100A. This is measured using a load resistor with a value that makes the voltage drop across it match the input range of the Analog pins of the Arduino. This is all discussed on the OEM website . I'm using the Arduino at 3.3V, so the "burden" resistor value is  R = V/I where V = AREF/2 (AREF is Arduino Reference) I = PeakSecCurrent => R = (AREF/2)/PeakSecCurrent Substituting  PeakSecCurrent = PeakPriCurrent/Turns => R = (AREF/2)/(PeakPriCurrent/Turns) Substituting PeakPriCurrent = (RMSPriCurrent * SQRT(2)) => R = (AREF/2)/((RMSPriCurrent*SQRT(2))/Turns) Substituting AREF = 3.3 RMSPriCurrent = 100 SQRT(2) = 1.414 Turns = 2000 (3.3/2)/((100*1.414)/2000) = 23.34 Ohms  Closest  I can get to this value is by pairing some resistors in p...

openenergymonitor.org is about "Open source monitoring for understanding energy", and the  efforts  of some stalwarts who have designed, constructed and had manufactured a  number  of  monitoring devices and supporting  software. These are currently based on Raspberry Pi and the Atmel chip used in the Arduino UNO , along with 433MHz radio comms and lots of open source software. The designs are comely open source, to the extent that you could build your own if you were prepared to have SMT PCBs made and so on.  I am interested in monitoring our energy consumption on a more fine grained basis than the 30 minute intervals that BG, in their wisdom, allow limited access to on their website, based on our "Smart" meter (as a SMETS1 device, not smart at all in fact). So the emonPi , with its RPi and an Arduino-stack based monitoring "hat", as a single box device that supports current, voltage, meter pulse sensing a...

 Another in the occasional series of domestic equipment repair stories! We replaced our condemned (no, really, the dishwasher repair man came, saw our hob, and said “You really should not use that again, it’s really dangerous!”) hob in 2015, with an AEG HK654200FB PNC 949 595 108 01. It’s a pretty standard effort, and like all home gear, is made of the same parts as every other one of the Electrolux brands. We love it, it’s really fast, really clean, highly controllable and many a fine meal has been cooked on it.  AEG HK654200FB Induction Hob The product label Sadly (to borrow the word of the last two years) half of it died last week. The right hand pair of cook areas don’t heat up, there’s a repeatedly clicking relay, all the controls work, but no heating action. The left hand side fortunately is fine. Off to the AEG support website, looking for parts, if only to see what kind of thing might be wrong with it, and get some idea how much it might cost to fix. The original came ...

A friend of mine has a dog that keeps losing its ball. You throw it, it catches it, it wanders around with the ball in its mouth for a while, then puts it down whilst your attention is also wandering for a moment, and bingo! It's lost. She sometimes finds it, but often not. How about a ball that enables tracking by some means?? At least, on a theoretical basis, leading to a prototype of some sort. Yes, it's technological overkill, but an interesting challenge. Problem statement: tennis ball sized ball, sufficiently mechanically robust to handle being thrown, held in a dog's mouth, waterproof etc. easily powered or charged, low battery consumption or chargeable (wireless??) just has to give dog owner/operator a clue as to its whereabouts, in a large field, say 200x100m, getting close enough for a visual search is fine Bluetooth LE seems like a start. Range of 10m/30ft, which should work reasonably because it's usually in a field! I'm thinking about using...