I made a Heavy duty DIY FPV cloverleaf antenna using 3d printed parts to help the antenna hold its shape and survive heavy FPV bando bashing.
The antenna is constructed with 0.8mm copper wire pushed inside individual 3d printed petals of the cloverleaf. The petals are than glued to a unibody holder which holds them in place where they can be soldered to the coaxial cable.
The petal and body are all glued together with CA glue. The base is held on the coaxial cable only by friction but a layer of heat shrink tube can be used for added fixturing.
I made a DIY field charging pack for flying FPV drones and simultaneously charging your packs while on the field. It is made from 24 rufurbished li-po cells wired in 6S4P configuration. It has a capacity of 22000 mAh on 22,2 V or 490Wh. It can charge up to 20 pacs with a single charge.
Case will consist of 3 parts all machined in the house with a CNC router. The walnut layer will be sandwitched between the two aluminum layers and the aluminium plate, which will hold the switches in place.
Custom PCB and Keyboard layout
For the keyboard PCB design I followed A GitHub Guide and my past knowledge.
The PCB is eqipped with standard cherry style switch fooprints, an ATMEGA32U4, LL4148 diodes and an USB C port. I have also included cherry style stabilizer mounts and other passive components.
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.
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.
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€
I have already soldered the passive 0402 components which is shown in this video which I recordered it with my DIY smd microscope adapter.
I have also finished the amplifier housing. It is made out of alumimium and offer great rf shielding and heat decipation.
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.
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.
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.
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.
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.
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.
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
I made a digital wrist watch prototype based around STM32F070 paired with a generic 0.96 inch OLED I2C display. PCB is designed in a way that the OLED display fits the header and mounting holes. The microcontroller uses internal RTC with internal low speed clock oscillator for reading the clock values.
Oled display sits above the main PCB. It features a MCP73871 charge controller which can tel the microcontroller the state of charge and other faults regarding the battery. Two tactile push buttons are used for navigation and the remaing one is dedicated for waking up the microcontroller and oled display. Pcb is designed for use with a TEMT6000 light sensor which has not been implemented yet and will be used for adjusting the oled display brightness. I will be making mre modification to the PCB in the future.
I designed a complete enclosure to house my previously designed tpa3116 2x50w amplifier board.
The design includes a 10A fuse to protect the amplifier board in case of a short-circiut or a reverse polarity of the power supply. I also fitted the amplifier ic with a heat sink which help the amplifier to achive the desired 2x50W of output power.
The enclosure is equipped whits several 5mm banana plugs for power transfer and 2 pairs of audio signal jacks.