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HarryA

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Posts posted by HarryA

  1. In LTspice on selecting components open the directory [Power Products] in the listing find LTC3705 when you click on it you will see "Open this macromodel's example circuit" that will display the circuit. 

    You can select RUN and the output display will come up. You can poke around the circuit with the "red probe" and see the  various wave forms are there. You may know this already but other reads may not.

    Perhaps if you click on some other types there you will find more converters of interest; as it displays a brief description of each.

    The Analog site listed above is is busted. I got in once but never again. But if you search on LTC3703 off that page you will get some links that look like they may be helpful.

    This link seems to work. Gets you to where you can enter you requirements.

    https://www.analog.com/en/product-category/step-down-buck-regulators.html

  2. "  {Bluetooth} It is mainly used as an alternative to wire connections, to exchange files between nearby portable devices and connect cell phones and music players with wireless headphones."  You may violate some code of ethics by connecting two Bluetooth devices together by wire.

    https://en.wikipedia.org/wiki/Bluetooth

    One needs to know what type of devices you are  using to have any idea how to interconnect them. If they have speakers or phone connections that would be a start. Class 1 Bluetooth devices have a range of about 100 meters.

  3. As this chip is made by Analog  and Analog owns LTspice simulator the circuit appears in the simulator and can be explored there. The circuit there is slightly different. Note it uses the FDS6680A mosfets. If you want 10 amperes make sure the mosfets can handle the current.

    642473649_Buckconv3703.png.8899aaaaeb0a0a2821b4a08dd32e1ab1.png

    Go here and put in your requirements then you will see some 10 ampere chips:

    https://www.analog.com/en/parametricsearch/11491#/p5573=min|24&p5574=100|max&p5347=min|12&p5357=12|max&p5349=10|240&qsfv=vinmin|24_vinmax|100_vout|12_iout|10&p5362=Buck

  4. There is a lot to designing a dc to dc buck converter. For example see:

    https://www.maximintegrated.com/en/design/technical-documents/tutorials/2/2031.html

     

    You can buy one for far less than the cost of the parts to build one. See:

    https://www.amazon.com/Aceirmc-Converter-Adjustable-Regulator-Protection/dp/B0823MM1DV/ref=sr_1_6?crid=1AB7YZ4O9O8B0

    You may find complete circuits on the internet. The inductor is the tricky part . What to use as a core and how to wind it for 20 amperes.

  5. 6 hours ago, Delorean said:

    Hi, all! My Arduino ide software serial monitor is showing like firmware version : 0x0 = unknown WARNING :Communication failure, is the mfrc522 properly connected ? scan picc to see uid, sak, type, and data blocks.... can you help me .

    "scan picc to see uid, sak, type, and data blocks."  huh?

    The mfrc522 supports three interfaces: 

    • Serial Peripheral Interface (SPI)
    • Serial UART (similar to RS232 with voltage levels dependant on pin voltage supply)
    • I2C-bus interface

    Which one are you using?

    What software are you using?

  6. Here are a couple of circuits that maybe helpful:

    https://www.homemade-circuits.com/dog-barking-preventer-circuit/#:~:text=Referring to the above shown dog bark inhibitor,using the IC2 and the speaker driver stage.

    and:

    https://www.electroschematics.com/dog-repellent-circuit/

    Perhaps a piezoelectric transducer would be louder than a speaker. Would require a different driver circuit. I used a device that women carry for protection that contains a piezoelectric transducer in my cat detector. That  is in the lower audio range of cause. It's very loud. I gather they work well in the  ultrasonic range as they are used in ultrasonic cleaners.

  7. I have for sometime now been dorking around with the MPU6050. I started out using Joop Brokking's code for a quadcopter
    but put it aside to educate myself on the PID software and the MPU6050 software. As you say there always seems to be problems with the MPU6060 code running away - the output of the formatted code seems to increase without limit.

    I am working with Joop Brokking's balancing beam code with and without the motors he uses to demonstrate using the MPU6050 and using the PID control software. That has the same problems.

    I migrated to Dejan_code.ino code because of its simplicity.  That has stable 'raw' outputs of the MPU6050. And is well behaved; in that if you rotate the MPU6050 to some angle it shows some stable raw value and returns to the zeroed values on rotating it back to zero angle. The values around zero angle only vary by plus or minus 10 or less - I call that stable.

    That code contains a calibration functions that displays the values required to correct the raw outputs to near zero.
    These values are used later within the code for corrections. Manually updated.

    I am currently using this code to understand why the formatted code output is unstable by displaying the values at various stages in the program.

    I also looked the Digital_Level_v1.ino code (the yellow level) but had problems getting it to compile. I get an error
    "no 'uint8_t MPU6050_Base::dmpInitialize()' member function declared in class 'MPU6050_Base'"
    related to the MPU5060_6axis_MotionApp20.h file.  This code is just to complex for me at this stage for what I want to do.

    The  Dejan_code.ino code is perhaps the beat code to learn about the MPU6050 from.  No PID!
    https://howtomechatronics.com/tutorials/arduino/arduino-and-mpu6050-accelerometer-and-gyroscope-tutorial/

     

     

  8. I used a infrared  transistor as a detector and diode emitter to make measurements on my quadcopter by having the blade pass through a gap with one on each side. You can get similar optical detector devices already mounted in pairs and separate them I would think.

    See this one for example: https://www.ebay.com/itm/402866611861?hash=item5dccb8a695:g:uUEAAOSwby1gql8L

    or unmounted: https://www.ebay.com/itm/274298671466?hash=item3fdd79916a:g:j~YAAOSwWNNdp9Dl

    The data sheet with circuit can be found here: https://www.digikey.com/en/products/detail/omron-electronics-inc-emc-div/EE-SG3/31139?s=N4IgTCBcDaIAQHkBKBWADAFgLQDkAiIAugL5A

    Perhaps an enclosure like this? 1513882846_fivewaypvc.png.a4288997f33816be3ec99b10145755d6.png

  9. It takes in the order of 200ms for the current to reach maximum in the simulator. The current through one coil is about 1.18 amperes. The voltage across the coils is about 200kv - you better wear rubber boots! Perhaps the simulator got carried away.

    There is an equation: time = inductance/resistance = 63% of the charge. So t= 0.380h /10 ohms would give 38ms. That would give 0.74amps at 48ms (38ms + 10ms pulse on delay) in the second waveform. That seems about right; at the white dot.

    Waveform14.png.8059a28ef71710e01fa9067aa64692a0.png280349974_waveform214.png.b39388f95e87269721fabea166bb25d3.png

     

  10. Using the circuit below with  an 2.5ms wide pulse at 10v  with rise and fall times of 100ns in the simulator I get the wave forms below.

     

    circuit2.png.485b4058a856647af9802a6d0467b505.png

     

    The green trace is the input at the base of the mosfet, the yellow trace is the current through one of the coils while the red trace is the voltage across the coils.  I will try increasing the pulse width until the current reaches steady state and see what is looks like and post it later.

    I do not understand the current.

    Circuit1Outputs.png.a6f5f6d986f74bd7ad0c8b1eedb0bea9.png

     

    Circuit.png

  11. 16 hours ago, Kerrowman said:

    So is the graph label ’Power Loss’ the back EMF at the drain? 
     

    And do you think any capacitance across the gate resistor would help?

    I am not sure about their graph either. You could try  playing around with a capacitor but I am  not sure how much  it affects the voltage drop rate at the output. As you are 95% there why not use an electronic ignition circuit? There are numerous  circuits like this one on the internet. You could get up to a few thousand volts then!1320123097_Car-Coil-1schemetic.png.208d110655708293d77166fa574bf990.png

  12. They often use a diode across your R5, I gather to discharge the gate capacitor to speed it up. See this link and click on the "simulate transient" for the IPP60R099CP.

    https://design.infineon.com/tinademo/designer.php?path=EXAMPLESROOT|INFINEON|Applications|Industrial|Power|&file=power_MOSFET_compare_450V.tsc&act=change.U.Infineon.IPP60R099CP_L0

    I wonder if the turn off delay of the 555 propagates through the circuit? The 555 off time is 2us compared to the equivalent timer 1455 at 100ns.

     

  13. I gather you are using the output from your speaker as input rather than a microphone.

    In the simulator I get, with zero signal, about 580mv dc at the transistor base and 600mv dc output (pin14).

    Using 1k sine wave at 10mv as input I get, at the transistor base, a signal between say 670 - 690mv, At the output pin14 0 to 3.5v.circuit.png.72babfa8d681e307e5ff59721de33bcf.png

     Using a 2SC2412K in the simulator which I believe is similar to the 9014.

    waveforms.png.d58f80ee3f545667e62d8a1813edce1b.png

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