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      Comparing MMANA-GAL with measurements of a biquad antenna

      pubsub.slavino.sk / avian_blog · Friday, 17 March, 2023 - 08:45

    I compared the simulated VSWR and reflection coefficient of a 2.4 GHz biquad antenna with VNA measurements.

    Značky: #Analog, #Elektro

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      Gas detector based on MQ-2 without microcontroller

      pubsub.slavino.sk / onetransistor · Saturday, 28 January, 2023 - 19:37 edit

    Nowadays people are using microcontrollers even for blinking an LED. And that is no problem, since they are cheap enough, have low power consumption and are easy to program. But there was a time when microcontrollers were expensive and hard to find. And even then, engineers were building working devices, just smart enough to do the job they were designed for. Let's try to build a "microcontroller-less" gas detector using one of the MQ sensors.

    Gas sensors from MQ family are analog tin dioxide detectors which change their resistance in the presence of volatile compounds like gases or smoke. Except MQ-7 and MQ-9 which are designed for carbon monoxide detection and require alternating heater voltage, with analog output being read at the end of each heater voltage cycle, every other sensor may be used in the following circuit.

    Gas detector based on MQ-2 without microcontroller
    Gas detector with MQ-2 module on breadboard

    Read more
    Visit One Transistor .

    Značky: #MQ-2, #Analog, #Sensor, #Gas, #Electronics, #Elektro

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      A footnote about ESP8266 5V tolerance

      pubsub.slavino.sk / avian_blog · Thursday, 5 May, 2022 - 14:28

    I measured the I-V curve of the digital IO pins on the ESP8266.

    Značky: #Analog, #Elektro

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      Effect of ground cutout on the CM4 antenna

      pubsub.slavino.sk / avian_blog · Thursday, 10 March, 2022 - 10:16

    I found that a Raspberry Pi Compute Module 4 PCB antenna on a carrier board with a ground cutout will on average have a 3 dB higher gain than on a similar board without the cutout.

    Značky: #Elektro, #Analog

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      Comparing RF Demo Kits

      pubsub.slavino.sk / avian_blog · Friday, 10 September, 2021 - 13:48

    I compared the behavior of SOLT calibration standards on the NWDZ and Deepelec Demo Kits and found that NWDZ performs better.

    Značky: #Elektro, #Analog

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      Inside a 3.5 mm plug from old Bose headphones

      pubsub.slavino.sk / avian_blog · Saturday, 28 August, 2021 - 08:16

    I found that the plug has an embedded passive filter and can't be reused for digital signals.

    Značky: #Elektro, #Analog

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      HackRF clock converter, 3

      pubsub.slavino.sk / avian_blog · Saturday, 26 June, 2021 - 08:48

    I show some initial observations of how the modified HackRF behaves when synchronized with ERASynth Micro.

    Značky: #Elektro, #Analog

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      HackRF clock converter, 2

      pubsub.slavino.sk / avian_blog · Friday, 18 June, 2021 - 18:18

    I assembled the clock converter board, modified the HackRF firmware and host tool and verified that everything works as intended.

    Značky: #Analog, #Elektro

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      HackRF clock converter

      pubsub.slavino.sk / avian_blog · Sunday, 6 June, 2021 - 08:24 edit

    I designed a small HackRF extension board that allows AC-coupled and sine wave signals to be used as a reference clock on the CLKIN input.

    Značky: #Analog, #Elektro