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  • DIY 1000mW 2.4gHz RF Amplifier

    BOM and gerber files now avalible:

    https://github.com/s52mp/OpenRcAmp

    SKY65162

    I designed a low cost 2.4ghz RF Amplifier based around SKY65162-70LF. The SKY65162 offers wide frequency operation range and is suited for both 900mHz and 2.4gHz both very popular in the RC comunity.

    The RF amplifier IC is a 400 to 3800 MHz Linear Power Amplifier that can output up to 30.0 dBm with 20.0 dBm gain.

    My Diy amplifier mounted on the turnigy 9x transmitter

    Schematics

    Passive components for 2.4gHz

    I created the chematics based on amplifiers typical aplication which also offers component values for its operation bands and than designed a 4 layer pcb following the manufacturers sample design found in the data sheet.

    PCB layout

    I calculated the prefered 50Ω impedace between first and second layer with the Saturn PCB toolkit using the PCB manufacturers PCB stackup. For 2.4ghz I calculated the track width to be 13,5 mils.

    For PCB manufaturing I arranged my designes in an array to maximize the PCB quantity that I could acquire for the same price.

    Amplifier all up cost

    My diy amplifier sould cost less than the solutions you can find on the market.

    costs per 1 PCB:

    PCB =~ 0,5€

    SKY65162-70LF =~ 2,93 €

    Passive components =~ 1€

    RF connectors =~ 3€

    Aluminium housing = Time spend on your CNC router

    All up cost =~ 7,5€

    Projects progress

    I have already soldered the passive 0402 components which is shown in this video which I recordered it with my DIY smd microscope adapter.

    https://youtu.be/o487bXXS3gA

    I have also finished the amplifier housing. It is made out of alumimium and offer great rf shielding and heat decipation.

    https://www.youtube.com/watch?v=7UdHx53yz0s&

    When the project is completed I will test its output power and RC link range increase.

  • Diy 5,8 GHz FPV patch antenna

    I made a FPV 5.8GHz biquad antenna from scratch. This makes it a linear polarized antenna mustly suited for flying tiny whoops and other drones with a linear polarised antenna.

    The tutorial includes the detailed construction of the antenna. Antenna has a 9-10 dBi upfront gain and 70% of the total gain at 60 degress, which makes it comparable to the middle priced patch antennas on market.

    5,8 GHz FPV patch antenna

    Parts required:

    • Coax cable with connector of your choice (I am using male SMA)
    • 50 x 40 mm blank PCB
    • 0.5-1 mm thick copper wire
    • Option: 3D printed cover

    Making the reflector

    From a black PCB cut out a 50 x 40 mm ractangle. (You can use any thin bladed saw but be careful of glass fibre dust that is not the best thing for your lungs.) To complete the refloctor mark and drill a 3mm hole in the middle.

    The reflector should look like this.

    Making the element

    To make the element cut the 0.5 – 1mm thick copper wire at 104mm.

    On the wire mark 8 13mm long sections and using pliers bend the wire in the correct shape. Using thinner wire will result in the easier bending but will be less structual rigit.

    The end element should look like this:

    Prepering the coax cable

    Upon acquiring the coax cable stip obout 1 cm of outer insulation.

    Once you have stripped down the insulation peel back the shielding to expose the inner insulation.

    At last remove the inner insulation to expose the center conductor.

    Assembling the antenna

    Firstly route the coax cable through the previously made reflector. Make sure that the distance betwen the end of the insulation and reflector is 6mm.

    Once the cable is inserted make sure it is facing straight out. Proceed with the soldering of the shielding to the reflector.

    Proceed with the most tricky part of the assembly: Soldering the element to the coax. Solder one end to the center conductor and one to the shielding. Make sure they are not touching.

    For the end you can 3d print a cover for your newly build antenna. STL file is awalible here: https://www.thingiverse.com/thing:4550555?fbclid=IwAR16yUGmdZZo_ozAh10Msc5Y5HOJ-F7W2w1ktqxOS49i9ML7czGfBLFo7pI

  • Budget FPV drone V3
    Budget FPV drone

    I designed and machined my own aluminium/3D printed frame for my new budget drone build. The frame weights about 120g, the whole build is about 500g.

    3D printed parts are avalible here: https://www.thingiverse.com/thing:4540281

    Build components:

    motors: 4x BR2205

    esc: 4x Hobbywing XRotor 15A

    flight controller: Sp racing f3

    reciever: Flysky FS-A8S

    camera: Foxeer Razer Micro

    video transmitter: TS5828S Micro VTX

    props: KINGKONG 5x4x3

    bec: Old broken esc used only for bec

  • DIY camera intervalometer

    I designed a camera intervalometer PCB. The intervalometer will plug into a camera and control how often and how long and how many shots will be taken.

    The PCB consists of STM32F0 microcontroller, TPS63031DSKT power supply switching regulator, which supplys 3V3 for the microcontroller and display from a single li-po cell. Li-po battery is charged through the USB port using MCP73811T charge controller. UI includes 5 navigation buttons and an I2C generic oled display.

    The project is in the production state. I will be posting updates when the project is finished.

    The pcbs were again provided by PCBWay who offer fast and reliable service. PCBs took 4 days to arrive. PCBs came well packaged. PCBs look good, even the 0402 solder pads are nice quality. The USB connector cutout is nice and square even the inner corners are square. I was happy with the PCB service, mostly by the fast shipping and production time.

    You can order your own PCBs here: https://www.pcbway.com/project/shareproject/DIY_camera_intervalometer_PCB_design.html

  • 2-way passive audio crossover

    I designed a simple 2-way passive audio crossover, consisting of 2 power inductors and 2 non polarized electrolytic or ceramic capacitors so this makes for a second-order design or 12 dB/octave. This order is commonly used in passive crossovers as it offers a reasonable balance between complexity and response. Higher order audio filters are harder to design, because components interact with each other.

    Second order passive filter schematics

    I calculated the component values for the audio crossover based on the Linkwitz–Riley capacitor and inductor ratios. I chose the cutout frequency to be at 4000 Hz. This value was choosen to better protect the tweeter from lower frequencies.

    Componenct

    The pcbs were provided by PCBWay who offer fast and reliable service. Packega came in fast, only taking 4 days to arrive. PCBs came well packaged. On the fist glance the PCBs looked good, the solder pads were nice and sharp. This was the first PCB that I ordered with a silkscreen and it also looked very nice. I was happy with the PCB service, mostly by the fast shipping and production time. You can order your own PCBs here: https://www.pcbway.com/project/shareproject/2_way_Audio_crossover.html

    Great quality PCBs provided by PCBWay

    If this is your first time ordering from PCBWay can also use my referral link: https://www.pcbway.com/setinvite.aspx?inviteid=353185 or visit their website: https://www.pcbway.com/

    I sourced all the filter components from Würth elektronik who offer great quality passive components.

    Pcb in a reflow owen