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Various JNZ developments
While waiting for the next JeeNode Zero revision, I’ve started on some examples and documentation for this new fun ecosystem.So there’s a bit of everything this week:Analog over wireless - WedSending...
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The JeeNode Zero rev4
It’s official: the first batch of JeeNode Zero rev4’s has been assembled, pre-loaded with software, and tested. Currently in transit from NL to the UK shop. It’s real now:There are a number of articles...
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A wireless rotary encoder
This week, I’ll be playing around a bit with a rotary encoder, wireless, and an OLED:But first, a brief tale of a belated little bug which caused a few surprises…Post-mortem of a bug - WedConnecting a...
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Bring in the Pies!
For production, fast re-flashing and testing of each JeeNode Zero is going to be a must. This week’s episode will be about speeding up the uploads, but also several ways to debug and test any STM32...
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No milk today...
Yikes. I’ve been felled by some bad stomach cramps and fever these past couple of days. Hence no articles this week - my apologies!The blog will resume next week, stay tuned.
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Keeping busy (in Forth)
Serial ports, radio packets, I2C devices… it adds up when you’re trying to keep many activities going at once. Luckily, there are some nice packages for Mecrisp Forth to help with this…This week, I’m...
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SD cards, interrupts, and DMA
This week is another potpourri of code for the STM32F103, the purpose of which will become clear next week… suspense!SD cards and µSD cards have a ridiculous amount of storage in a very small package....
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EZ-Retro is a Z80 running CP/M
And now something completely different!I’ve always been fascinated by those 8-bit computers that started it all. As a teenager, I spent many hours reading about them, but never could afford a Z80...
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EZ-Retro Z80 - part 2
Getting CP/M working on this two-chips-plus-a-blue-pill setup took more time than I thought, especially on the software side.This week, I’ll turn Forth into a peek-and-poke monitor for the eZ80,...
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Circular motions
Just back from a few days in Paris, visiting friends (a bit south of Paris, actually), but we did manage to squeeze in a stroll in the Jardin du Luxembourg - with memories of a (brief) childhood there,...
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Just a bunch of opinions
This week, I’ll report about some progress on the next EZ-Retro “v2” PCB and build (which isn’t quite right yet, unfortunately).But first, a topic which has been keeping me busy lately… typing and the...
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Back to Forth explorations
Now that the EZ-Retro project is beginning to wind down, I’ll start exploring Forth’s features and behaviour a bit more again.One of the distinguishing features of a fully self-hosted system like...
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Some Mecrisp Forth utilities
This week, I’m going to demonstrate some tools from the Mecrisp Forth distribution.A different prompt, math functions (even without hardware floating point), random numbers, call tracing/profiling, and...
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Going through the motions
The last word in last week’s introductory weblog post was “flow”. Let’s talk about that for a moment: what is it like to develop a Forth application for an embedded µC, and in particular a remote...
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2.4 GHz with a JeeNode Zero
The JeeNode Zero has always had two footprints for radio modules on its PCB. Apart from an RFM69 (or RFM12), you can also mount an RFM70, 73, or 75 on there:(this is the older “v1”, the new “v4” is...
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Revisiting the JET design
There’s not much point sprinkling wireless nodes around the house without also a solid central infrastructure to collect data and manage the outbound control requests.Some readers may remember HouseMon...
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Hello Pi-hole, goodbye ads!
It’s that time of year again: this is the start of “summer mode” for the JeeLabs weblog.Instead of weekly article series, there will be just one post per week, covering a somewhat wider range of topics...
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Quad 18650 power supply
Might not have been such a great idea to 3D-print this DIY supply I made in red:(it does look slightly alarming, I’m afraid)This is a little portable power supply I made a while back, with four very...
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Low-ripple HP power supply
I got a power supply from eBay a while ago:That’s an HP 6255A: 2x 0..40V @ 1.5A, max 80V in series. But the interesting spec is its very low noise: <0.5 mV and <0.2 mA.These supplies are very...
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UT61E 4½ digit multimeter
Ah, gadgets… can’t have too many of ‘em!It’s hard to think of anything more useful and relatively low-cost for the electronics lab than the venerable digital multimeter.It’s good to have at least two...
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