AEO-RC S1 Servo Tester w/ Gyro Sensor
AEORC's S1 servo tester is specifically designed to accurately measure the
servo speed and helps to understand the overall performance. AEORC's S1 servo
tester is the first integrated servo tester in the market which allows you to
measure speed, duty cycle, travel linear & range also receiver output signal
Input voltage: 8~12V (2S lipo or 9V 2A DC power supply)
Output voltage: 5V
Output current: 1A
Accuracy: 1us +/- 10%
Operating temperature: -10~50°C
1 x Servo tester
1 x Gyro sensor
1 x voltage regulated multi-functional servo extension wire
The AEORC S1 Dr Servo is a tiny box using the same packaging as the clever
kV meter. It consists of a servo driver and an input for an
accelerometer that you attach to the servo’s output disk/arm. That input
measures the pulse position so is also used to test receiver servo outputs.
It also requires an external 8-12V DC supply. They suggest a 2S LiPo, but
after using it I would recommend a 3S. The lower voltage just does not seem
to have quite enough headroom to supply the 5V to drive the servo at higher
currents. Most folks will probably be using the BEC from their ESC to drive
the servos in any case – see the three way cable description later.
The inside of the accelerometer is just a sealed unit
with a part number that I could not raise on the internet with an external
diode and resistor. I suspect it is the same unit used in single axis piezo
helicopter gyros. AEORC call the device a ”gyro” and I’ll do the same for
simplicity. The only control is one of those 4-way joysticks with a centre
push that you find on every compact digital camera. Long push to move
between the 4 screens; up/down/sideways to select a value if appropriate;
short push to turn the backlight on and off or start a test. In my view it
would have been more logical to make the short push for menu change and long
push for backlight/start. The backlight keeps going on and off when you
don’t want it to and on the other hand you have to dwell on a screen to
change to the next one. This results in an unwanted test starting sometimes.
No big deal, and doesn’t detract from the functionality - just an
In use, you just plug in the external battery, connect
the servo and gyro and stick the gyro to the servo output disk or arm with
foam tape. Alternatively you can use the gyro input to test transmitter
stick range and centring. There are 4 functions on the tester:
1. Display of
receiver output signal pulse width to the servo channels in thousandths of
mS with a default neutral of 1.500mS (handy to very conveniently check how
consistent the range and neutral your transmitter channels are). A
servo-plug to servo-plug cable is supplied for this and you connect the gyro
channel into each receiver output in turn. The supplied connectors are
Futaba style and the ridges have to be cut off to allow the plugs to line up
along the edge of the S1. Minor, but irritating. This menu must also be used
to set the signal pulse width to give a 60 degree rotation (since the pulse
length to do that may vary from servo to servo).
2. A cycle
test that logs the number of repeating input cycles together with the number
of output cycles recorded by the gyro (good for testing suspect servos). It
reads up to 9999999999 cycles which for a 0.1sec servo would be a total test
time of about 31 years if I have done the math correctly!
of servo travel linearity, which is really no more than setting up 2 or 3
servos side by side and comparing them as they are driven at the same time.
of servo speed, which is the uniquely useful and important function of this
To measure servo speed, you first need to tell the S1
what pulse width gives 60 degrees rotation. It’s remarkably simple to
position the servo over the protractor they have printed in the manual and
use the joystick to move the servo from the neutral position. When the holes
in the horn line up at 60 degrees, you just read off the pulse width,
subtract the neutral value and adjust it on the measurement screen with the
joystick. It turned out to be much easier and more consistent than I
expected. My guess is it is accurate to a couple of degrees if you are
careful to align your eye with the shaft of the servo on the baseline.
Obsessive can set up a more accurate rig to measure rotation precisely. Then
you just push the button, the servos cycles a couple of times and the time
to move 60 degrees is displayed in 1/100th’s of mS (more on accuracy later).
You can do 10 readings in as many seconds. If the servo doesn’t respond, a
long push upwards on the joystick reverses the signal – neat.
This is the simple way, and uses an internal regulator in
the S1 to provide 5V at a max of 1 Amp to the servo. If you want to measure
at the “standard” 4.8V then use any of the servo connectors on the supplied
three-way splitter lead which then plugs into the S1. See attached picture TestSetup.jpg.
The lead contains a 220µF capacitor to provide some reserve for peak current
draw and a forward connected series Schottky diode in the main lead which
drops the 5V to almost exactly 4.8V and protects the S1 from external
voltages from the branch leads at the same time. Very simple and clever. If
you want to measure at a different voltage, say 6V or use your ESC’s BEC,
then just plug an external supply into one of the three servo connectors.
Results for AEORC S1 Dr Servo
Initially, no servo worked for me without an external
battery supply. Changing the 2S 1000mAh battery supply to a 9V 2.5A power
supply made no difference. I measured 0.46V at the servo supply connector.
AEORC were helpful and responsive but in the end I discovered the Schottky
diode in the harness was assembled in reverse (it’s very hard to spot the
band on the diode). Once fixed, everything worked as expected. Be worth
checking if you have the same problem.
The sensor weighs 9.5g so can be used on quite small
servos. There is no simple way to calculate what the inertial load of the
sensor is on the servo of course so it isn’t quite “unloaded”. Here are a
few sample results averaged over 6 cycles.
Using a stabilized Lab 2.5A supply:
See Table 1
Using a 40A ESC with 4S 5000mAh LiPo: BEC voltage
measured at 5.16V for same servos as above.
See Table 2
Using without any external supply gives approx 4.85V at
Results without external supply for 3x Bluebird
BMS-375DMG – 11.4g.
Claimed speed at 4.8V = 130mS. Three identical
out-of-the-box, unused servos.
See Table 3
For fun: Some old servos of late 70’s vintage
See Table 4
The Orbits were the ultimate small servo at the time,
have served me well, and cost a fortune. They still hold up not too badly 30
years later! The Charlie’s (Cannon in kit form) were the smallest servo
available and a feat in their day – but look at the response speed.
Like many digital display devices this one reads out to
unrealistic precision. The specs say accuracy is 1µS +/- 10%. “10% of what?”
is the issue. Times in µS are reasonable for measurement of signal pulse
width but not servo movement. There is no information on precisely how this
gadget works but I assume it just measures the time between start of
acceleration and end of deceleration. There is going to be some imprecision
about this no matter how good the timing circuits are. I would suggest a
basic accuracy of perhaps 1 mS for servo traverse is both reasonable and
entirely adequate, not the 10 µS that is displayed. I found variations over
10 cycles of less than 3 mS with a new Hitec servo on a 6V supply so I’m
assuming the S1 itself is probably good for at least 1 mS accuracy and
anything more is servo variation. In other words I think what the specs mean
is the READOUT is good to 1 microsecond not the accuracy. In any event this
is more than adequate. It’s pretty clear from the numbers above that the
variation between cycles and between individual servos of the same type is
significant. In general the better the quality of the servo the less
variation. Those old 70’s Charlies servos I built from a kit were a wonder
in their day but a HobbyKing $2.99 special leaves them for dead!
I did quite a number of tests on different servos using a
variety of power supplies and I came to the following conclusions:
This is a uniquely useful device. There are other servos
testers of varying complexity but all the ones I have seen are really just
servo drivers. I am unaware of any other low cost device that actually
measures the servo cycle speed. Be interested if anyone knows of another.
It is low cost and simple to use. Once you get the hang
of it you can test a bunch of servos in a few minutes. I found surprising
variation between “identical” servos and also between specified and actual
performance – particularly at the low-cost generic end of the spectrum.
I’m not into helis but I know there is a great need for
speed in the tail rotor servo in particular. This would seem to be a good
Our warranty/ return / exchange policy is very simple. If the item we sent you is defective when you received the shipment from us (NOT AFTER USE), you can report to us by email for return / exchange / refund arrangement.
Request(s) for return or exchange and report(s) of missing or damaged part(s) must be received within 30 days of your receipt of merchandise(s). We reserves the rights to entertain requests received thereafter.
Items returned must be in as-new conditions with the packing slips, manuals, accessories and all other items intact in original packaging. Returned merchandise must be received from our customer before we will process and ship out any replacement. All merchandise should be returned to us by shipping carriers with safe method which provides proof of shipment (just in case your item does not reach us. so you can check with your local shipping carrier.) We will not responsible for the lost of returned merchandise in shipping.
Shipping and handling charges for all orders are non-refundable, as we have paid the Post Office to send the shipment and the Post Office will NOT refund the postage cost back to us after they processed the shipment. Customer will be responsible for the return shipping cost to send return back to us. For returned merchandise that is found to be genuinely defective, we ship out replacement for free (we pay for the replacement shipping cost) and will not charge additional shipping and handling fees.
We reserves the right to return merchandise to its customer and not refund money, if we in our opinion deem that the merchandise has been used, crashed, abused, misused or modified in any form, or has been damaged by water, dust, or other contaminants.
*** All items are tested by manufactures to make sure they are working properly before we ship them to our customers.
*** Please inspect the product when you received the shipment, identified any issue and report to us BEFORE you try to fly / use it. Please also check over the product (especially the helicopters and air planes) and make sure they are all good every time before use (or taking to the air).
*** Return / exchange / refund is not allowed if the item has been used or flew. Please understand that RC helicopters and airplanes can crash if mistake made or you do not know how to fly, any kind of crash or hard landing may caused damage(s) to the helicopter or plane. We have no control over your flying skill, behavior or the conditions you have chosen to fly in. We tested all products before shipment as we stated above, if you have any problem with the aircraft or other product(s) you ordered from us, please report it at the time when you received the shipment (not after use please).
*** If you used / flew the product, or crashed product, no matter what the reason. We are sorry but we can not be responsible for your crash or use. Hobbypartz.com will not be responsible for incidental or consequential damages including bodily injuries and property damages arising from the use of any product(s) that it sells. Hobbypartz.com reserves the right to refuse service to anyone. Remote controlled products and accessories can be very dangerous. Please read the operating manual before use. We have no control over the correct use, installation, application, or maintenance of our products, no liability shall be assumed nor accepted for any damages, losses or costs resulting from the use of the products. Any claims arising from the operating, failure or malfunctioning etc. will be denied. We assume no liability for personal injuries, property damages or consequential damages resulting from our products.
*** These terms applied to all sales made from our website, email, phone, or fax. If you do not agree to our terms, please do not make the order.
We reserves the right to amend this policy without further notification(s).
To experience 5-Star Customer Service & Tech Support from HobbyPartz.com, visit us at RCDiscuss.com
|You may also be interested in: Quick Pick, Select Application, RC Planes, Airplanes Accessories, Meter/Tester, RC Upgrades, RC Planes, Airplanes Accessories, Meter/Tester, RC Planes, Airplanes Accessories, Meter/Tester, , New Products, For RC Planes, RC Planes, Airplanes Accessories, Meter/Tester, |