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Micro ESC from servo driver
I wanted to be able to control the brightness of some LEDs from Ardupilot flight controller.
I wanted 0 to 100% pwm output from the FC pin to drive the gate of a FET, then you can control anything (LEDs/motors/solenoid/etc), but Ardupilot does not have that function. Ardupilot has servo passthrough function, it passes a RC channel from the Rx through the FC to a output pin. This will require a brushed motor esc, most of them are larger than the size of the FC, and fitting them on a 5" quad is a bad choice. Then I found on AliExpress for $3 shipped, a servo motor esc (for continuous rotation servos). I got one and have tested it on the bench, its got some issues that I was not expecting. 1. Most Tx/Rx will not output below 1000us and above 2000us, this means you will maximum get +/- 70% speed (see picture). 2. Lowest PWM output is 17.5% 3. Maximum 6V. Maybe possible to modify for more voltage by cutting the FET driver supply trace and feeding more voltage, but I have not found the datasheet to the FZMOS-5X (so-8 package). Large zero thro dead band 1390 to 1591 (200us) See the attached picture for the PWM info. So with the limitations of 6v, 1A, 17% to 70% max output, it will work out of the bag and its low cost and tiny. AliExpress INFO: 1pcs DIY Dual-way 1A Mini ESC 5V DC Brushed Speed Controller Module Winch Control Bidirectional Driven Circuit Board for DIY RC Part https://www.aliexpress.com/item/1005...36e34c4duQeMF3 Specification: - Size: 12x8.5mm - Voltage: 3.5-6v - Continuous current: 1A, maximum current 1.5A - PWM range: 1000~2000US (Warning, its a LIE) - Wire length: 200mm - Motor cable length: 20mm - Single board weight: about 0.4g (not include wire) - BEC output: None - Dual way,can be positive and negative, - Applicable motor: brush motor - Compatible with Futaba, JR, SANWA, Hitec and other remote control systems Application: - RC Mini Car, DIY model airplane,rc mini drone / multicopter aircraft - Remote control model car,winch control circuit and other model parts - Used for 360 degree continuous rotation servo Feature: Digital circuit, no need potentiometer to adjust the stop position ATX_Heli wrote: fyi you can get 800 to 2200 output to that device controlled by an RC input channel....takes a little slight of hand...(With ArduPilot) what you do is you use a camera mount output function... say, assign a servo output to camera pan function....then that servo output range can be changed to 2200 to 800, which you cannot do if its RC_Passthru...then use MNT_DEFLT_MODE=3 (rc targetting) and MNT_RC_IN_PAN= whatever channel in to control it....and MNT_TYPE = 1(servo) and wrote: btw, you can set the output limits to any PWM value, not just 800-2200.... you have to use the full parameter tree editor, but I have used 2400 to 500uS (yes some servos actually accept that range..almost all will take 800-2200us....many normal 90 deg servos will get almost 180deg if you put in a bigger PWM range)... avoids using a servo pulse stretcher on my pan servos |
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Last edited by --Oz--; Jan 30, 2021 at 12:25 AM.
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