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Bertrik Sikken
144 followers -
Open source, bats, electronics
Open source, bats, electronics

144 followers
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Built a simple frequency counter for measuring the mains frequency this weekend. It's giving interesting results already: at 22:00, 23:00, 0:00 and 1:00 (CEST) you can see a bunch of dips. Probably because of extra load being added to the grid. At 6:00 and 7:00 (CEST) you can see bunch of peaks, possibly the utilities anticipating for extra power usage in the morning.

Project page: https://revspace.nl/MainsFrequency
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Sand clock, seen at hacker space Bitlair in Amersfoort, Netherlands.
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I've been playing with the "ESP-Now" mode in ESP8266-based boards like the Wemos D1 mini. This mode allows you to send wifi-frames without having to set up an ip-address between two nodes.

The ESP-Now protocol gives you the ability to send a packet of up to 250 bytes, you get an ACK back (or not) to know if the receiver got the message and you can even protect the packet with encryption.

I plan to use this in our hacker space for the music "skip button". This thing is a portable button that anyone in the space can press to skip to the next song if they don't like the current song. Important features are that it's a portable (battery powered) and has low latency between a button press and the actual audio skipping to the next song. In combination with the ESP deep sleep mode this results in a very low power system, sleep current is 0.16 mA and active mode for a skip is currently only 200 ms.
Project page: https://revspace.nl/EspNowSkip
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What piece of unfriendly software is this language learning tool 'anki'?
It claims "Exception: Qt 5.10 is known to be buggy." and then quits, LOL.
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Very much liking this framework so far:
https://platformio.org/

It allows you to build, upload, debug Arduino programs without having to use the awkward Arduino IDE. Just a text file in your project directory that says what board you use, what libraries, what serial port settings, etc.
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Ordered an USB-VGA converter that can apparently be used to transmit radio signals. The converter is basically configured as a high-speed DAC. This could be the thing for radio transmission what the rtl-sdr is for radio reception.
https://osmocom.org/projects/osmo-fl2k/wiki/Osmo-fl2k
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http://luftdaten.info is a pretty cool project, collecting data from fine-dust sensors all over Germany and they're accepting data from other countries too. Their network is now so extensive that can actually see fronts of fine-dust if you play back a time lapse. My own fine-dust sensor ( https://revspace.nl/DustSensor ) is now also a dot on their map :)
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While looking for some information to finally do something useful with the set of "HM10" bluetooth low-energy modules I got some time ago, I ran into this awesome project:
https://hackaday.io/project/2386-bluebasic-basic-for-bluetooth/details

It's a basic interpreter running directly on the embedded microcontroller (TI CC2540/CC2541) that is typically inside these BLE modules.
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The plantower PMS7003 dust sensor that I plan to play with in the coming days. I knew it was rather small, but now appears even smaller than I thought. This sensor gives an estimate of airborne dust in 6 particle size categories over serial out. There's even a little fan inside to keep the air moving. The connector has a pitch of just 0.05 inch, a suitable plug is on its way too.
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