User:Bertrik Sikken: Difference between revisions

Latest revision as of 19:42, 26 October 2024

User info Bertrik Sikken
Name	Bertrik Sikken
Nick	bertrik
Tagline	heb ik niet

You can reach me at bertrik@sikken.nl or bertrik@gmail.com.

Studied Electrical Engineering at Twente University.

Main interests:

reverse-engineering things (USB stuff, mp3 players), worked on http://rockbox.org (sansa clip players)
studying bats and making electronics for recording/listening to bat sounds
radio stuff, in particular software-defined radio
energy-related stuff, visualisation
citizen science, particulate matter measurement, noise

Projects I work(ed) on (refresh):

	Project Status
FrontDoorDisplay	Abandoned
HabAlertApp	Abandoned
ISSO	Abandoned
IbmPosDisplay	Abandoned
Pico Trackers	Abandoned
RadarOnAStick	Abandoned
WifiLamp	Abandoned
A4PaperDispenser	Completed
BuildStatusTrafficLight	Completed
CJMCU-811	Completed
CO2MeterHacking	Completed
CrawlSpaceSensor	Completed
DecodingLora	Completed
DustSensor	Completed
ElectronicLoad	Completed
EspNowSkip	Completed
Intakefancontroller	Completed
LichtKrant	Completed
LoRaGateway	Completed
LoraBatBox	Completed
LoraWanNode	Completed
MHZ19	Completed
MainsFrequency	Completed
MiniSTM32F103ZE	Completed
PowerLight	Completed
RC522Hacking	Completed
RevRadio	Completed
STM32	Completed
Secure iButton	Completed
SoilHumiditySensor	Completed
StofAnanas	Completed
Stofradar	Completed
TTNHABBridge	Completed
VINDRIKTNING	Completed
ZigbeeCoordinator	Completed
Sensor-data-bridge	Completed
AntiLost	In progress
AudioMoth	In progress
CubeCell	In progress
EspAudioSensor	In progress
Esp32cam	In progress
FMCWRadar	In progress
Karaburan	In progress
LoRa-E5-mini	In progress
LoraWanDustSensor	In progress
MainsFrequency2.0	In progress
Msi2500SDR	In progress
MysteryLidar	In progress
Sim7020	In progress
StereoBatRecorder	In progress
... further results

Project ideas

This is a list of ideas I'm thinking about, but have not fully developed into an actual project yet.

https://pine64.com/product/128mb-ox64-sbc-available-on-december-2-2022/

Remote bat box monitor

Idea:

goal: check if remote bat boxes are occupied and identify the species
challenges:
- connectivity: need to transport images/videos (no LoRaWAN), possibly out of range of mobile data networks
- autonomy: cannot reach the bat box once installed
- power: no fixed power connection, so probably needs a battery + solar panel
design
- wake up every hour, take a picture, go to sleep, upload photos/videos once per day
- run from batteries, recharge by solar, rules of thumb
  - batteries should last for about 10 days
  - battery should be able to charge in 1 day
  - consider only 10% of peak solar power
- KPN "4G-op-zee" somewhat confusing article: https://www.kpn.com/zakelijk/mobiel/roaming/noordzee
hardware
- main processor: raspberry pi zero
  - raspberry pi power consumption overview: https://www.pidramble.com/wiki/benchmarks/power-consumption
- this hat to wake up the main CPU: https://www.waveshare.com/wiki/Power_Management_HAT_(B) sold at https://www.kiwi-electronics.com/en/power-management-hat-for-raspberry-pi-with-rtc-and-rp2040-mcu-11373

KNMI API

Get familiar with https://developer.dataplatform.knmi.nl/open-data-api

Grid frequency measurer with web page

See https://github.com/bertrik/GridFrequency SSE source is gridfrequency.local/events

WeAct CH55x board

Cheap little boards, using a similar chip as used in USB-serial converters.

The hardware https://github.com/WeActStudio/WeActStudio.CH552CoreBoard

Flashing it: https://hackaday.io/page/137447-flashing-the-ch552-dev-board-from-the-command-line

Zigbee device with esp32

See https://github.com/P-R-O-C-H-Y/arduino-esp32/blob/8169a434c3e46e1bb7711ebcc04f27267db2093c/libraries/ESP32/examples/Zigbee/Zigbee_Light_Bulb/Zigbee_Light_Bulb.ino

See https://github.com/espressif/arduino-esp32/tree/master/libraries/ESP32/examples/Zigbee

Espressif32 arduino platform git: https://github.com/platformio/platform-espressif32

Cameratoezicht in Gouda

Gemeente Gouda publiceert een lijst van camera's in Gouda, zie https://gis.gouda.nl/viewer/app/Basis_open?bookmark=57b682c39eb8426c81a67934044517c9

Aanmelden (semi-automatisch) bij bijvoorbeeld Surveillance-under-surveillance ?

SolarEdge

Interact with the solar edge api for PV installations.

https://developers.solaredge.com/

See https://github.com/bertrik/solaredge-api

Stookalert

Idee: gekleurd lampje dat aangeeft of er op dit moment een stookalert actief is

Implementatie:

kijk m.b.v. WiFi locatieservice in welke provincie je je bevindt
haal JSON op bij https://www.lml.rivm.nl/stookalert/stookalert.json
toon de bijbehorende kleur op het lampje

Resources:

Officiele pagina: https://www.atlasleefomgeving.nl/stookwijzer
Achterliggende JSON met toestand per provincie: https://www.lml.rivm.nl/stookalert/stookalert.json
Er moet ook nog ergens een API zijn die fijnmaziger aangeeft wat de toestand is ...

Display of current electricity usage

I have a slimme lezer connected to the P1 port of my smart electricity meter. The default firmware exposes meter readings using an event stream (SSE) at http://slimmelezer.local/events

So for example, you can read this with curl:

 curl http://slimmelezer.local/events

With result:

 event: state
 data: {"id":"sensor-power_consumed_phase_1","value":0.046,"state":"0.046 kW"}

Specification of SSE: https://html.spec.whatwg.org/multipage/server-sent-events.html#parsing-an-event-stream

What I would like to do is to read these events and control a simple display to display the current usage number.

Participating in ultrasonic sound project

https://bat-migration-europe.netlify.app/project/

Use an audiomoth for this.

ESP32 C3

Flexible LED ticker

Ordered a flexible 32x8 RGB LED display: https://nl.aliexpress.com/item/4001296811800.html

Matching diffuser to be 3D printed: https://www.thingiverse.com/thing:1903744

Washing machine API

https://tratt.net/laurie/blog/2023/displaying_my_washing_machines_remaining_time_with_curl_jq_pizauth.html

TinyML

Investigate TinyML, see https://www.tinyml.org/ Apparently can run on a RP2040 (raspi pi pico).

https://www.hackster.io/mjrobot/esp32-cam-tinyml-image-classification-fruits-vs-veggies-4ab970

Bat box busy signal

My brother built little pyramid 'blinkies': solar cell + Lithium-supercapacitor + harvesting circuit + LED encased in clear expoxy.

Can we add a low-power PIR sensor to this, and make a blinky that blinks if movement was detected by the PIR in the past hour?

Super tiny RFID

See https://www.sparkfun.com/products/16464 an almost sand grain size RFID chip, 1.25mmx1.25mmx0.55mm

The accompanying reader "M6E Nano" is still quite expensive at $235.95 : https://www.sparkfun.com/products/14066

Uses the MuRata LXMSJZNCMF-198: "This product can be used as an ultra small tag and this can be fit on any metal objects, non-metal objects, as well as embedding into any objects by glue or adhesive and so on."

See also: ISO18000-63 and EPC global Gen2(v2)

Specification:

https://www.gs1.org/standards/rfid/uhf-air-interface-protocol

TheThingsNetwork-Sondehub bridge

Uploads balloon telemetry to sondehub.

See https://github.com/bertrik/ttnhabbridge/issues/6

Actually smart boiler

The boiler for hot water is about half of my electricity bill. The idea is to use/build a smart switch that switches it on at time when electricity prices are lowest.

Currently have a "Slimme boiler module" from Eneco, which is *not* actually smart, since it allows me no control whatsoever when it switches on (besides cutting the power in the meterkast). For example, it will switch on mid-day when my price is high and eneco's price is low, perhaps good for Eneco, not for me. Apparently, they even received a subsidy for this.

A boiler is a pretty big load, about 3 kW, but it is not inductive.

Alternatives:

https://www.shelly.cloud/en-nl/products/product-overview/shelly-plus-1-pm-2-pack/shelly-plus-1-pm
https://www.solyxenergy.nl/solar-iboost/ to store excess solar energy in hot water, might also be useful for just controlling a boiler to use cheaper rates
tuya smartplug, like https://www.wifilampkoning.nl/merken-slimme-verlichting/tuya/tuya-enkele-smartplug-met-energiemeting ?
tuya 20A smart plug: https://nl.aliexpress.com/item/1005003347568206.html

Receiving gas meters

Apparently gas meters send gas consumption data to the slimme meter using a wireless link in the 868 MHz band. Probably just FSK at 38.4, as mentioned here: https://a35.veron.nl/nieuwe-elektra-en-gasmeters/

Interesting leads:

Multi-network wifi manager

Figure out or create software so that ESP8266/ESP32 wifi manager can use multiple networks to connect (not just one), so it allowing storing credentials for more than one network. For example, the network at home, the hacker space, at work. Instead of reconfiguring the wifi manager for each network, you just *add* your credentials (and the existing credentials are not replaced).

See https://github.com/folkertvanheusden/M.A.X.X

Interesting candidates:

https://registry.platformio.org/libraries/martinverges/ESP32%20Wifi%20Manager wifi manager for ESP32, has a REST API for managing wifi network, but is incomplete in the sense that you need to write your own code (e.g. javascript) to actually *use* its API
https://github.com/arduino-libraries/Arduino_MultiWiFi is the arduino multi wifi library, to allow connecting to multiple different WiFi networks, but it is not a wifi manager, that starts a captive portal, etc

Automated bat counting

Can we automatically count the number of bats from the image of a webcam mounted in a bat colony? Perhaps using some kind of AI or machine learning algorithm?

The image in question: https://stofradar.nl/coenecoop/

Use TheThingsIndoorGateway as Helium/ThingSix hotspot

I have a spare TTIG that could perhaps be used as a Helium gateway, investigate what is possible.

One possiblity is to capture the gateway traffic from the TTN gateway events API, convert uplink data to a format that the Helium network understands and forward it. I don't really care about the Helium crypto tokens, this is just for fun and science.

What I definitely can do:

Capture data from the TTN gateway events API, convert it back to Semtech UP format and forward it somewhere to Helium (just not sure where!)
See also my https://github.com/bertrik/ttn-gateway-collector project which contains an initial implementation of TTN-to-UDP conversion

Showstoppers:

If you want to be a gateway on the Helium network, you have to *pay Helium*! Obviously I don't want that, I just want to share data to improve *their* network.

Open work:

Investigate if Helium has an open uplink API for their hotspots, if so study it etc, without paying the gateway fee
Investigate if Thingsix has an open uplink API for their hotspots, if so study it etc, without paying any gateway fee
Investigate if Thingsix is just another Helium, with weird crypto money

Interesting stuff:

https://docs.helium.com/use-the-network/setup-a-packet-forwarder unfortunately the link to setting up the 'light hotspot client' does not work!
https://docs.helium.com/mine-hnt/light-hotspots/
https://thingsix.com/

Adding BLE GATT interface to sensors

The GATT specification allows measurement properties to be defined and transferred continuously over Bluetooth low-energy.

With GATT you can define a collection of properties (e.g. measurement items like temperature/humidity/particulate matter/noise, etc) organised in a simple structure of a BLE service. The 'notification' method allows you to basically push the data continuously to a connected host, e.g. a smart phone.

Services collects characteristic, a characteristic has values with units. Each of these (service, characteristic, unit) have their own unique "UUID". This is described in the so-called 16-bit UUID numbers document

Interesting stuff in GATT:

See GATT_Specification_Supplement_v5 paragraph 3.151, it has a noise characteristic with 1 dB resolution.
0x27C3 is the GATT *unit* for sound pressure
0x181A is the GATT environmental sensing *service*, document name "ESP_V1.0.0.pdf"
0x2A6E is the GATT Characteristic and Object Type for temperature
0x2A6F is the GATT Characteristic and Object Type for humidity
0x2BD5 is the GATT Characteristic and Object Type for Particulate Matter - PM1 Concentration
0x2BD6 is the GATT Characteristic and Object Type for Particulate Matter - PM2.5 Concentration
0x2BD7 is the GATT Characteristic and Object Type for Particulate Matter - PM10 Concentration
Unfortunately I cannot find a characteristic for carbon-dioxide (CO2) in the BLE GATT unit document

Reverse engineering XS-8217 bluetooth air quality meter

This is a thing that measures CO2, humidity, temperature, TVOC and formaldehyde.

This teardown looks a lot like my sensor: https://www.youtube.com/watch?v=APnjhMrJChI Mine contains a "TPM-300A" sensor for measuring VOC.

It has a bluetooth interface, device name is XS-8217. It has a BLE GATT profile, with the following services

service 0xC760
- characteristic 0xC762 (WRITE)
- characteristic 0xC761 (NOTIFY)
  - example data: 0x23 0x06 0x10 0x04 0xF1 0x00 0x23 0x65
  - example data: 0x23 0x08 0x10 0x04 0x01 0x9A 0x00 0x0A 0x00 0x03 0x0E
  - data shown on screen was approximately: CO2=418ppm, HCHO=0.003mg/m3, TVOC=0.013mg/m3, temp=24degC, humi=35%

So data in the characteristic 0xC761 seems to have a 4 byte constant header:

0x23
length byte

Then we have for the first message: 0x10 0x04 0xF1 0x00 0x23 0x65

0x10 0x04 fixed header
0xF1 is temperature in 0.1 degree Celcius most likely (24.1)
0x00 is ...
0x23 is humidity most likely (35)
0x65 is ... checksum perhaps

And for the second message: 0x10 0x04 0x01 0x9A 0x00 0x0A 0x00 0x03 0x0E

0x10 0x04 fixed header
0x01 0x9A is the CO2 concentration (410)
0x00 0x0A is TVOC most likely (10)
0x00 0x03 is HCHO most likely (3)
0x0E is ... checksum perhaps

ribbon tweeter for bat audio

Someone gave me this idea: Use a ribbon tweeter like this for playing back bat audio: ~~https://nl.aliexpress.com/item/4000973201791.html~~ https://nl.aliexpress.com/item/1005002565880660.html

The frequency spectrum shows no sign of dropping off at 20 kHz.

3d glasses

I got some 2nd hand 3d glasses, they look exactly like these ones:

The common name appears to be "G15-DLP".

A tear-down here:

https://blog.danman.eu/3d-shutter-glasses-teardown/

Interesting documents:

Someone claims he got something to work with some hacks: https://www.avsforum.com/threads/how-i-got-cheap-dlp-link-glasses-to-work-great.1887145/

Waterniveaumeter

Op verschillende plekken in Gouda staat er water in de kruipruimte van huizen van bewoners. Kunnen we dat meten en inzichtelijk maken, voor bewoners, op een kaart bijvoorbeeld?

Idee:

in de kruipruimte plaats je een module die waterhoogte kan meten
de module bestaat uit een microcontroller en een afstandsmeter, die de waterhoogte bepaalt
de gegevens worden via WiFi doorgestuurd naar een centraal punt, waar de data wordt verwerkt en gevisualiseerd
op een webpagina kan je een overzicht zien van alle meters die online zijn
de meting wordt gedaan door bijv. een laser-afstandsmeter of een ultrasoon-afstandsmeter
voeding? lastig, hoe krijg je 5v naar een potentieel natte plek?
kosten? verwachting < E 40,-

In Gouda wordt op veel verschillende plekken de grondwaterstand gemeten, zie https://opendata.munisense.net/portal/wareco-water2/group/581/Gouda-KJ38A , maar:

geen visualisatie op de kaart, je ziet alleen de meetlokaties d.m.v. een icoontje!
geen meetpunten in Gouda noord!

Online bat detector

Idea: use an ultrasonic microphone, connect it to a WebSDR, so people can tune into bat sounds remotely.

Raspberry pi airplane tracking

Apparently now you can also participate in MLAT tracking of planes that don't transmit GPS coordinates themselves.

APRS gateway

http://qso365.co.uk/2017/02/a-guide-to-setting-up-an-aprs-receive-only-igate-using-a-raspberry-pi-and-an-rtl-sdr-dongle/

JQ6500

Small inexpensive modules that play mp3 from an internal flash. Could be nice for a custom door bell for example.

More info at:

FPGA

Cheap FPGA boards and nice applications:

Neural networks on low-end hardware

Investigate if you can run a powerful neural network on relatively low-end/cheap/low-power hardware. For example a Raspberry pi. A RPI runs Linux, run python, just like some common neural frameworks. Do we need hardware acceleration from the GPU and does the RPI GPU support that?

Read list:

Bought a MaixPy:

mini word clock in dutch

Basically an monochrome 8x8 word clock, in Dutch, showing local time in the Netherlands.

This git repo has the current code.

See here for a demo running on an arduino nano.

The plan is to run this from an ESP8266 instead of an arduino nano, so it can get the time from the internet using NTP. Andreas Spiess demonstrated on youtube how existing libraries on the ESP8266 can be used to do the local time (including summer-time) calculations.

Cypress PSOC5

Play with the Cypress PSOC5 platform, which combines a ARM Cortex-m3 processor with configurable analog blocks. I'm thinking of combining it with a 24 GHz doppler radar sensor, to process the signal and present it as a USB audio device (stereo signal contains I and Q parts). See RadarOnAStick.

Simple Doppler motion sensors

You can find basic doppler microwave motion sensors based on a single transistor, with some weird traces on the PCB very cheaply, for example

https://www.aliexpress.com/item/RCWL-0516-microwave-radar-sensor-module-Human-body-induction-switch-module-Intelligent-sensor/32708877914.html

Typically the microwave part of these consists of a single transistor with a rectangular area on one leg and a meandering trace (with lots of vias to the other side) on the other leg. The output of this circuit seems to go into a chip very much like the ones used in PIR sensors.

See also https://github.com/jdesbonnet/RCWL-0516 for a reverse engineering effort of these doppler radar modules.

Bare-bones Arduino bat detector

This is an idea for a very basic heterodyne bat detector, doing signal processing on an Arduino, requiring minimal external components.

The basic principle of a heterodyne detector is that it just mixes (multiplies) the audio signal with a square wave, low-pass filters the result and puts it on a speaker.

Multiplying with a square wave can also be considered to be just alternatively inverting and not-inverting the signal. So if you sample an ultrasonic signal at twice the rate you want to multiply, you can just subtract odd samples from even samples and low-pass filter that.

How this can be done in an AVR Arduino:

sample the audio signal at twice the detection frequency, say 84 kHz. An AVR should just be able to do that.
apply a 1-pole IIR high-pass filter to remove DC bias, this takes one shift instruction and one addition.
multiply by the detection frequency, this means just inverting the odd samples.
low-pass filter the signal, this can be done using a moving average filter, say 16 samples long (first null at 5.25 kHz). Theoretically, averaging 16 samples should result in two bits extra accuracy. This operation takes some storage, an addition and a subtraction.
output the filtered signal using PWM, possibly at the same rate that we are sampling the input audio.

The microphone can be a 40 kHz piezo transducer, to keep it cheap (but also limited to 40 kHz). The pre-amplifier can be a single transistor with some resistors around it, providing about 40x gain. The arduino does the signal processing (mixing, low-pass filter) to shift the bat audio to human range. The speaker amplifier can just be a simple two transistor push-pull circuit, since the output from the Arduino is digital/PWM.

AVR Arduino sample rate

As far as I understand, the ADC clock can be set to 1 MHz. Conversion takes 13 cycles, so this can be a problem to reach a sample rate above 80 kHz.

Indoor radar speed sign

This idea about placing a simple IQ-output radar sensor indoors in the hacker space, do some basic signal processing on the IQ doppler signal and determine movement speed and direction, then display this on a LED display. This is of no immediate practical use other than fun, but helps me to gain a bit more experience with microwave radar sensors and eventually build a more effective setup for detecting/counting bats flying in and out of a roost.

Implement this on a PSOC5 platform or on the STM32 using Arduino.