środa, 9 października 2013

Motor speed controller is ready

I've finally finished my electrical motor speed controller box to use with line winder. It is based on a chinese PWM controller bought for about 12$ on aliexpress.com. It can deliver up to 15A with voltage range of 12-30V.

I've added voltage meter, amp meter and a rotary switch. Switch is used along with electrical relay to connect and disconnect PWM controller to the motor. In the future I'll add additional PWM controller and some artificial resistance load to create electrodynamic motor brake to control speed at which the line will be unwound (usefull especially with high wind speeds). What is really neat,   when potentiometer is set to "0" PWM controller shorts both motor wires together -  force needed then to rotate the engine manually is so big it prevents line from unwinding when pulled by kite.

Electrical relay switch coil circuit is rated for 12V so I added additional resistors  to prevent it from damaging when 24V is applied.

środa, 4 września 2013

First tests of the kite line winder

Kite line winder prototype using 24V 250W electric motor (12V supplied during test) - full success :). About 3-4A of current drawn when pulling kite at moderate wind. Next priority is  PWM speed controller and a fancy switch and cable box. Winder weights about 7 kg  and was designed to fit into standard car trunk, although next version will be much smaller - as you can see there is a lot of free space on the frame.
I got inspiration from http://beachwinches.com page - a lot of great DIY winch designs.

poniedziałek, 29 lipca 2013

Kite lifted transmitter - experiment 1

Purpose of the first experiment was to test my new kite - HQ PowerSled 36 and its lifting capabilities. Smaller kites (like PowerSled 14) give too small pull to lift even 500g payload at moderate winds.
Final goal is to have platform that allows lifting a 1000g payload in winds at 10 km/h or greater.

Payload: custom made APRS tracker (based on Arduino Nano) with 5W Wouxun KG-UVD1P transmitter and GPS receiver. Antena was simple 144 MHz quarter-wave, unfortunately - bent 90 degree during experiment. Payload weight: about 600g.

Custom-made APRS tracker

Wind speed: 25 km/h - according to the Warsaw-Okęcie (EPWA) airport weather service.

Max altitude: 160 m above ground level (measurement based on GPS record). About 250m of kite line was used.

Altitude graph

Longest RF signal path (based on http://aprs.fi measurment): 106 km


2013-07-13 17:17:26 CEST: SQ5OMQ-1>BEACON,WIDE1-1,qAR,SR5DRK:!5211.11N/02122.09E-TRACKER NA LATAWCU
2013-07-13 17:17:58 CEST: SQ5OMQ-1>BEACON,WIDE1-1,qAR,SR5DRK:$GPGGA,151724.000,5211.1068,N,02122.0938,E,1,07,1.1,227.4,M,38.8,M,,0000*56

SR5DRK station received over 14 consecutive APRS frames, so the RF path can be considered stable.

Experiment notes: At 25 km/h wind, PowerSled 36 gives so strong pull that it's very difficult  for 2 persons to get it back on ground. Heavy, electric engine powered line winder is needed for further experiments. Construction of such winder is under way.

Goal for the next experiment: Tests of the winder, reaching altitude of 300m above ground level. Different mount of the radio antenna to get better efficiency.


HQ PowerSled 36

Kite and transmitter in the air