Tag Archives: do it yourself

DPS3005 Digital Power Supply

DPS3005, 0-30 V, 0 – 5 A Laboratory power supply

DPS3005 is 30V, 5A adjustable power supply. It has great options as is: over-voltage protection, over-current protection and overpower protection. This setting is for maximum ratings that you apply before anything else. For example, if you read datasheet for some electronic product, and it says has some maximum voltage and/or current ratings, you may set this values as a maximum values – where PSU will cut off power in the case that those limits are reached.


Input parameters

Input voltage should be 1.1 V above maximum wanted voltage, but not less than 6 V.  Absolute maximum voltage should be no more than 35V. So, when constructing power supply, transformer with rectifier and filter capacitors (electrolytic capacitors) should not go over that value of 35 volts. In the case of 35 V input, it can give us little bit over 32 V output. For those who want higher voltage, there is another model: DPS5005, which gives up to 50 V (little bit more). Both are 5 A output capable.

Video review

Here is one video that describes main functions of DPS3005 PSU:

Simple connections

Just provide ‘+’ and ‘-‘ wires at +Vin and -Vin, then connect wires for the output at +Vout and -Vout, and that is all. Output ripple voltage is 100 mV peak to peak. It can be further filtered by external capacitors, for example 100 nF + 100 uF capacitors paralel to Vout connectors. Ripple voltage is at relatively high frequency (not 50/60 Hz), thus easy to filter out. Some inductive coil (choke) can be added in series between Vout connectors and capacitors mentioned above for even better filtering. DPS3005 is very good protected device – even repeated short circuit at output is tolerated.

Constant voltage

For most application we want constant voltage. Just pres yellow button with V/up (arrow up), then rotate dial. Dialing button has option to select precision of increments, so push button and select steps at which it will change numbers on the display: 0.001 V, 0.01 V, 0.1 V, 1 V or 10V steps. If there are no over-voltage event, it will work fine.

Constant current

Sometimes we need constant current limitation. The same steps as with Constant voltage, but this time bottom yellow button pressed to chose constant voltage settings.

Electronic circuit breaker

There is no such thing per se, but rather interesting way to protect circuit from over-voltage, over-current and over-power protection. In the menu, selected after pressing yellow ‘SET’ button, using arrows (also yellow buttons up/down), there are options to set ‘OVP’, ‘OCP’ and ‘OPP’ protections. OVP is for over-voltage protection – sometimes may happen that our circuit is connected to other PSU, and ‘back-fire’ some higher voltage out, so this OVP will react and turn off PSU. OCP reacts exactly as circuit breaker, which just turn off peacefully whole PSU. OPP is new thing – it calculates power based on formula P=I*U (power equals current multiplied by tension), and reacts depending of our settings in the menu for OPP.


It is cheap and affordable PSU. Only what you need to add is some transformer with rectifier and filtering capacitors, or as I did use another existing non-regulated PSU and you have really good regulation, protection and accuracy. Accuracy is about 0.1% which is really good for prices less than $30 US – on Banggood, DPS3005, or DPS5005 version.

Stay tuned!

DIY quadcopter: FrankenDrone

Maiden of “FrankenDrone”,  DIY quadcopter

So far, managed to record video maiden (first flight) of my new “FrankenDrone”, DIY quadcopter. It has JJ1000 controller board, gears and propellers (props) from Syma X5C, with 7×20 mm motors.

Upgrading stronger motors

Now upgraded to FY326 gearbox and motors 8.5×20 mm. My flight with Mobius camera onboard failed because microSD card has some problem with deleted files. Camera showing that it recording, but I can’t find video files on microSD card. Now, after quick format, everything works fine. Here will be updated status of the experimental flights.

The difference between gearboxes of Syma X5C and FY326 Q7

Syma X5C, as well as its clone Bayangtoys X8 has some problem with vertical “play” of the main shaft which holds props. Gearbox with motor mount and prop mount has no such problem, or it is very minimal play, maybe 0.5 mm, while Syma X5C and Bayangtoys X8 has this “movement freedom” of about 1-1.5 mm. It is not a problem during flight, since props pulling this shaft up, and gears are aligned perfectly. But, noticed that gearbox from FY326 (original designation of this quadcopter is Q7) is more silent. On Syma X5C gearbox, I can clearly hear strange noise produced by movement of pinion and gears, while on gearbox from FY326, this noise is very low.

Further improvement

Gearbox has 3 x 3 mm square profile, but I found only 3 mm round aluminium rod, and used it. The problem with this rod is that aluminium by default is hard to drill – broke 3 drills and did not make hole for screw to fix it properly. Now found better option on Aliexpress, but so far… haven’t money to buy. It will be long(ish) waiting until it happens. 🙁

Excellent carbon square,  3 x 3 mm can be found here.


For more range & installing buzzer

I already modified JJ1000 remote with “V” antenna, and should to upgrade similar antenna on the quadcopter to get maximum possible range, since I want to fly it FPV. In order to avoid duplicate post, anyone interested in extending range, can found it on my webpage here. Note that diagram on this page is for Syma X5C, and Bayangtoys X8. On JJ1000 board, installing buzzer is much simpler:

quadcopter buzzer

Just solder +ve of the buzzer on cahtode of the diode, and -ve on drain of the MOSFET which run on/off LEDs on the quadcopter. After binding, buzzer whistling all the time, and then press right “shoulder” button for 3 seconds to turn LEDs and buzzer off. Battery alarm will sounds and LEDs will blinks. In the case of lost quadcopter, just turn of remote, and buzzer will sounds, LEDs will blinks. Easier to found.

Choice of the buzzer

At first model of my FrankenDrone, I am using buzzer from some programmable LEDs which has buzzer in between, but this option is bit expensive. Then ordered buzzers from Aliexpress – little one, just 0.67 grams. But it is big disappointment – not loud enough. Reason why I wanted so light buzzers is to install it on smaller quadcopters, but this one is big and has no such issue with little bit heavier buzzer. This one from Banggood.com is the best option:


The rule about buzzer

For indoor flight, quiet buzzer is okay, but this makes no sense to install it when indoor flight – you always can find your quad. The louder the better. If it does not give you “instant headache” when sounds, it is not good for outdoor flight with quadcopter. Consider next situation: strong wind blows away your quadcopter, and it flyaway into some bush. The same wind may be sufficiently loud to “override” volume of some small and silent buzzers. So, louder is better. This one above is sufficiently loud, but I want more, still searching for cheap yet louder one. 🙂

Become my ‘permanent Banggood friend’ by applying this CODE if you already haven’t Banggood account. You will buy at no additional cost, and I will get some points which helps me to make more exciting projects. Thank you in advance.

The ultimate WiFi antenna at 2.4 GHz

Good antenna? But, simple to build? YES!

Why bother with antenna?! Note that antennas are most important things for every transmission and reception. Aside use for quad-copters, airplanes and other flying bests, it works extremely well on WiFi Router/Client. On Router put “straight” or slightly angled dipole as is described on video as antenna for quad-copter, and for client – which may require some directionality – the “V” shape antenna is the best option.

The only difference which is not covered in this video is use of proper SMA connector. On quad and remote, I just soldered antennas at proper pins, while for WiFi – it is good to chose proper SMA or RP-SMA (Reverse Polarity SMA) connector, depend of where it is intended to use.


I strongly recommend use of RG316 coaxial cable, which is bit thicker than RG178, and has lower attenuation. It is your choice.

Which connector?

SMA Female Jack To RP-SMA Male Jack RF Coaxial Adapter Connector is the best, yet cheap connector for this purpose. Does not require crimping tools, but require patience and soldering iron. First solder center wire of the coax into hole, then put some glue to prevent short circuit. After glue (epoxy 2-component for example) cures, solder braided part of the coax all around. This way it is secured electrically and mechanically, while maintaining good properties of the antenna and low attenuation.

I can’t make ‘sleeve’ from braided part of the coaxial cable

I know. It is bit tricky and require patience. In the case of very thin cables, it is even more difficult. In this case, you may consider to do next trick: do everything as above, but instead moving inside-out braided part, leave 1-2 millimeters of this part so that additional part can be cut out from other piece of cable. Then move it from opposite end, until this 1-2 mm overlaps, then solder it carefully. This is maybe easier way to do this. Enjoy in such great antenna!