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A new design, moving to 32-bit
With one of the two main energy metering nodes out of order, it’s becoming more urgent now to implement a replacement. It would be a shame to break the cycle, after some 8 years of data collection, all...
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Going 32-bit, at last
Given last week’s mishap, and the resulting damage to the main metering JeeNode, it’s time to start creating a new setup. While I’m at it, I’ll throw a few new measurements into the mix and will also...
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Energy monitor requirements
The meter cupboard is - as one would expect - the place where lots of energy-related matters come together. Here is the situation as of early 2016 at JeeLabs:Note: that “JeeLabs Energy Monitor” is...
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Powering from an AC source
Ok, we have a name: “JeeLabs Energy Monitor” - and we have a board to use: the Olimexino-STM32. As mentioned before, that board has a number of convenient features for this project.Then again, any...
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Reading out the pulse counters
Unfortunately, progress on pulse input recognition has been a bit slow - partly due to unrelated “time sinks” - so this will be an overview of some other details of the JeeLabs Energy Monitor.The...
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Upstairs, downstairs
It turns out that tinkering and development is hard when the signals to be measured are located far from my desk and electronics workbench. The meter cabinet is located downstairs next to the front...
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A remote console w/ ESP-Link
The ESP-Link is a clever project, which turns an ESP8266 WiFi module into a transparent serial link - sort of a wireless FTDI interface. Thorsten not only created a really powerful software package for...
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Measuring AC supply voltage
With the JeeLabs Energy Monitor prototype hooked up in the meter cabinet, it’s now very easy to explore things a bit. One interesting test is to look at the analog signal from the AC power supply +...
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When an input pin isn't one
The article about the ESP-Link ended with what turned out to be an ominous note, in hindsight:There’s still a buglet in this setup: the “reset” word leads to a runaway loop of “Unhandled Interrupt...
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This week's potpourri
This week will be a hodgepodge of topics which I’ve been working on recently: a hardware interaction which kept me really puzzled for quite some time, a delightful excursion into the deeper innards of...
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Great ADC/DMA performance
For the “JEM” JeeLabs Energy Monitor, we’re going to need to put the ADC on the Olimexino’s STM32F103 to some serious work: the goal is to acquire 4 ADC channels at 25 Khz each, so that we can capture...
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Some µC speed measurements
Not long ago, Ken Boak very generously donated one of his assembled PCB designs to JeeLabs:This is a break-out board for the STM32F746VG, an ARM Cortex M7 CPU with floating point and a whopping 1 MB...
View ArticleWorking on JEM
The JeeLabs Energy Monitor prototype is progressing nicely - once I figured out that I had my numbering of the Arduino analog pins 0..5 reversed… doh!Here is what’s on the menu for this week:Tracking...
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Tracking pulses w/ interrupts
There are three pulse counters for measuring power at JeeLabs - one for solar PV production and two for the kitchen stove and the rest, respectively:These generate 2000 pulses per kWh, that’s one pulse...
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Frequency aliasing in ADCs
This is a pure sine wave, captured by the ADC + DMA code, as described previously:The plot above consists of 800 samples, sampled 40 µs apart, i.e. at 25 kHz - for a total of 32 ms. A quick calculation...
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Simple variable packet data
Until now, most of the wireless sensor nodes here at JeeLabs have been using a simple “map C/C++ struct as binary” approach as payload format. The advantage of this is that it simplifies the code in C...
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Tying up several loose ends
This week is yet another mixed bag of topics, all related to either the JeeLabs Energy Monitor, or taking the STM32F103 platform further with Mecrisp Forth.It might not look like much from afar, but...
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Parsing P1 smart meter info
The smart meter at JeeLabs looks like this:It’s a Landis & Gyr E350, which monitors all power coming into the house and going out (when solar PV production exceeds local consumption). There’s an...
View ArticleThe need for multitasking
With an increasing number of sensing and reporting activities taking place on the JeeLabs Energy Monitor (JEM) prototype, things are starting to become a bit more complicated.How can we deal with such...
View ArticleUsing a buffered serial console
Mecrisp Forth comes with a serial-port command line interface. This makes both tinkering and uploading new code a breeze, but it’s nevertheless a fairly limited setup:no input buffering: if characters...
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