| spec
| @904570
| Plantraco Micro Receiver with Electronic Speed Control
| DSP4-SC Specifications
|> Operating Voltage |< 2.5 to 18 Volts
|> Bandwidth |< &lt;10 KHz - exceeds AMA standards
|> Adjacent Channel Isolation |< 60dB
|> Sensitivity |< Better than 5 uV
|> Current Drain |< 16mA @ 9.6V
|> Receiving Range |< up to 1 mile
|> Crystal |< Use Plantraco crystal only
|> Modulation |< Narrow band FM, -ve shift
|> Tx Compatibility |< Futaba/Hitec
|> Dimensions |< 0.625&quot; x 1.5&quot; x 0.5&quot;
|> Weight |< 4.5 - 8 grams
| Built-In GFS! Electronic Speed Control
|> Rated Current |< up to 10 Amps
|> BEC output |< 5V, up to 1.5 Amps
|> Switching Frequency |< 2 Khz
| Plantraco - http://www.plantraco.com

!Introduction

The Plantraco DSP4-SC Micro Receiver with Electronic Speed Control grabbed my
interest for that fact that I could get a receiver and electronic speed control as one
unit for a very reasonable price. Traditionally, electronic speed controls and receivers
for brushed motors are sold separately. The Plantraco DSP4-SC promises to
deliver as good, if not better, performance than traditional electronics.

I had just completed building the GWS
Tigermoth, and was excited about the slow flying possibilities of this widely
regarded plane. It seemed the Plantraco DSP4-SC would be a perfect fit
in this virgin test bed.

I noticed that within the plastic casing shell, the board was loose. Upon closer
examination, I realized this was so the plastic protective wrapping could be
removed and shrink-wrap heated on, to save even more weight. I decided for the
review to leave the casing on, as the unit was so light already, and the
weight savings would be minimal.

@904570:9 grams. Definitely a light-weight.
@904571:Not a lot bigger than the crystal and servo receptacles. It would be hard to miniaturize these units any further.

Plantraco sells
lithium polymer batteries, with their own brand of connector.&nbsp;
A female connector was attached to the battery connection of the DSP4,
and also provided was a spare set of wires with a male connector attached to
solder to one's own battery.&nbsp; I
thought this was a very nice touch, and would feel very confident using their
plug since the two plugs joined very securely together, without any movement.
The instructions give easy directions for hooking up Plantraco LP Lithium
Polymer cells using the supplied connectors, but I had already decided to fly
my little Tigermoth with Qualcomm Lion batteries with Deans Micro plugs, as I
have Deans already attached to my Qualcomms.

Reading the one
page instructions, which are labeled as “Quick Start Instructions”, they
provide the basic warnings about keeping the motor lead wires short, to avoid
overheating larger motors.&nbsp; The
instructions also recommend wiring the Plantraco DSP4-SC directly to the
motor. I decided against this, as
I like moving my equipment from plane to plane, and the Plantraco DSP4-SC is
rated to 10 amps. I knew that I
could power not just an IPS motor with this little device, but also EPS
motors, and the Deans would function just as well.

As I was
soldering the Deans on, I realized, that in effect I actually was holding a 4
1/2 channel Receiver in my hand.&nbsp; Since
the ESC is already a part of the Receiver, I had another channel to play with.&nbsp;
I read through the one-page instructions that came with the Plantraco
DSP4-SC, and they don’t mention whether the throttle stick on my Transmitter
would control channel 3 on the Platraco DSP4-SC. I was presuming at this point
it did, but if a person, say, had a set of lights that they wanted to control
through the throttle output, or a set of landing gear that when you throttled
down would engage, you would plug into channel three, saving the fourth
channel for whatever one wanted.&nbsp; This
is a nice thing to have if a person wanted flaps or any other control that
required a fifth channel, no Y harness would be required.&nbsp;

Also, a 4.8 v NiCd or single Lithium cell can be plugged into an unused
set of connector block pins as a power source to power the receiver. You
cannot operate the electronic speed control in this fashion though!

I use hook and
loop fasteners for all of my radio equipment. Slipping the Plantraco
DSP4-SC into the narrow space within the Tigermoth was very easy.&nbsp;
This unit only comes with vertical pins, so keep this in mind for your
placement. The instructions show proper servo plugging into the connector
block pins, great for those new to plugging in connections.&nbsp;&nbsp;
I would say that the Plantraco DSP4-SC is almost a plug and play unit.

@904572:Slipping the Plantraco DSP4-SC into the narrow space within the Tigermoth was very easy. This unit only comes with vertical pins, so keep this in mind for your placement.

The Plantraco
DSP4-SC is rated up to 10 amps or more, but Plantraco claims it is actually
capable of delivering over 12 amps of current.&nbsp;
They do recommend installing a fuse between the motor and the DSP4-SC
when using any combination capable of drawing more than 12 amps.&nbsp;
I did not test this, as I do not fly any planes that require this much
power, but it is good to know I have this option.

One
of the claims made of the Plantraco DSP4-SC is that it will not arm the servos
or motors until the proper RC signal is detected.&nbsp;
I tested this on the bench. Sure enough, with my transmitter off, I
plugged my battery in, there was no servo twitching at all, the motor didn’t
turn on, and there was no sound at all coming from the unit.&nbsp;
I tried this three times, and didn't see a single glitch.&nbsp;
Turning my transmitter on, with the battery still plugged in,
activated the receiver, again, with no glitching.&nbsp; This is a
wonderful feature, as we all have those moments where we are a little absent
minded.

I also retested the safety-arming feature by
plugging my battery in with my transmitter off with other transmitters on in
the area.&nbsp; Once again, I got no
servo jitter, or sporadic motor start up common with other receivers.&nbsp;

@904573:Qualcomm 830 Mah Pack and Built Tigermoth comes to a weight of 8.9 ounces.

!At the Field

The
Plantraco DSP4-SC has a range of 1 mile, but I knew I wouldn’t be flying
that far away, so did a range test of 500 paces.&nbsp;
I had no problems, and everything worked flawlessly.&nbsp;
On my little patch of baseball infield, I held the plane and slowly
built up throttle.&nbsp; Plantraco
claims that the built-in speed control has something called a Time
Domain Filtering algorithm, which will always increase or decrease motor speed
smoothly, greatly reducing motor and gearbox stress.&nbsp; I have no idea what a Time Domain Filtering is, but algorithm
is defined as:
&nbsp;&nbsp;A
step-by-step problem-solving procedure, especially an established, recursive
computational procedure for solving a problem in a finite number of steps. - The
American Heritage® Dictionary

This definition really meant nothing to me, and I’ll
leave it to other Ezoners to hash out a definition of this feature, but what I do know is that each
click on my transmitter brought the throttle on the Plantraco DSP4-SC up smoothly and cleanly, so the Time Domain
Filtering algorithm seemed to do it’s job.&nbsp;

Once I let the Tigermoth get air born, I had
smooth response from all my servos and throttle was consistent with no
glitches.&nbsp; Other planes in the air
also had no effect on the Plantraco
DSP4-SC, and I felt very comfortable with other frequencies on. I felt very
safe and confidant flying with it, and highly enjoyed the smooth throttle
control.


If the Plantraco DSP4-SC detects no radio signal for 1 second, the
motor will cut out. Throttle control returns when the radio signal is once again detected. I fly in
an area with a bit of radio interference, and “hits” are common. At one point
during my slow flight, I must have received some interference as I temporarily
lost control of the throttle. The servos all functioned normally but the motor switched off.
After a brief loss of throttle, the motor turned back on.

This did not require in-flight re arming of the electronic speed control, I didn’t even have to
move my throttle stick.&nbsp; This
feature is something to be conscious of, so you are not caught unawares if it
happens.&nbsp; The feature is designed
to prevent your plane from flying into the wild blue yonder or straight into
the ground.

This loss of signal
is so rare though, that I have confidence that this would not happen indoors,
and outdoors I had it only happen once in my 20 some odd flights. The
Plantraco DSP4-SC seems to filter out quite a lot of noise and interference
from other radio signals.

@904574:The Tigermoth flew nicely with the Plantraco unit.

!Conclusion

For a brushed ESC package, the Plantraco DSP4-SC is an excellent value, and an outstanding performer.&nbsp;
I’ve flown the Tigermoth with the unit for 20 flights, and still am
getting exceptional performance.&nbsp; The
only two negative features of the DSP4-SC are that it only comes with vertical
pins, and will only work with Futaba/Hitec, or negative shift transmitters.&nbsp;
This is unfortunate, as those on positive shift would really enjoy this
unit as much as I do.&nbsp; I would have no hesitations of picking up another few units
for my other brushed motor applications.

I have this receiver and really like it. If I had an "extra" $60 I would buy another one. It is really cheaper than buying a seperate comparable receiver and speed control, plus it weighs less and is smaller.

The only things I wouild change are the vertical pins, since I usually have really small and tight planes and that the crystal usually comes loose after swapping the receiver back and forth between planes. I usually just put a little tape on it.

Originally posted by Matt D.
I have this receiver and really like it. If I had an "extra" $60 I would buy another one. It is really cheaper than buying a seperate comparable receiver and speed control, plus it weighs less and is smaller.

The only things I wouild change are the vertical pins, since I usually have really small and tight planes and that the crystal usually comes loose after swapping the receiver back and forth between planes. I usually just put a little tape on it.

Matt,

That's exactly what I had to do, was put tape over the Xtal.

I had a cheaper RX, and had a crystal fall out on a bad landing, luckly it was on landing. Scared me enough to put that safety harness of a small piece of tape over it.

Geof.
www.smoothair.rchomepage.com

Yes, tape the crystal. It is fragile.

I really like this receiver. The only issue I have with it is the FETs. I had one in a micro helicopter. The helicopter tipped over on its side and the FETs blew in the open position. The motor continued to turn and the heli beat itself to death like a flapping chicken.

The receiver ESC was shot. I called Plantraco and they said this is the way the receiver was designed. They replaced it for a nominal fee which was nice of them. Very good customer service. I don't use them in micro helis anymore.

OK, I am new--
My radio is 72.590
The receiver I have is 72.670
I take it they must match
But this is what the hobby shop said I needed?
Did I get taken?

Originally posted by niceguy2254
OK, I am new--
My radio is 72.590
The receiver I have is 72.670
I take it they must match
But this is what the hobby shop said I needed?
Did I get taken?

Niceguy,

I don't think so.....but maybe go into the radio forum and ask...

Have you tested it, and does it work?

Geof.
www.smoothair.rchomepage.com

Just to add something to this little RX/ESC

I've flown inside with it in a couple of places, one of which had electrical wires hanging down from the ceiling. At least 3 other planes were in the air inside, and I had no hits, radio interference, or twitching common to other RX.

This RX has performed flawlessly. For this price, you really can't go wrong.

Geof.
www.smoothair.rchomepage.com

I fly JR.
Doesn't work for me.
But would be willing to try a JR unit indoors.
Crash

Originally posted by jbourke
Traditionally, electronic speed controls and receivers for brushed motors are sold separately.

I have one of these:

http://www.simprop.de/Seiten/Modellb...croScan4+1.htm

All of the above + PLL synthesized frequency.... , no crystal to drop out. Only 35 and 40 Mhz afaik. Works for me, even though I often have motor cutouts (quickly switching on/off remedies that...)

On my initial flights the DSP4-SC is working Ok for me too.

The interesting thing is that this Rx demonstrates that very low servo step resolutions will work for sport flying. The DSP4-SC's microcontroller limits the servo resolution to about 200 steps per full stick range, which is about 7.5 bits of servo resolution. But more resolution would be nice.

RC-CAM

Edit: Update. The DSP4-SC is seeing glitches at my two favorite flying sites. Others are reporting this too.

Hi Morb - I just jumped in here, but surely you MUST have a compatibility problem when you are 4 channels apart! Your Tx is on Channel 40 and your Rx is on Channel 44.

"Something is rotten in the state of Denmark!" (W. Shakespeare)

Cheers, Phil

Yup, you guy's were right, My radio was 40, and the reciever was 44. Bought a new one and every thing work's. Now to have a nice windless day to check out how it fly's.

P.S. The person that sold me the wrong crystal, would not take back the other one, that he said was the right one! OH well, live and learn, it was only 5 buck's.


Thank's for all your help!! Bryan

Originally posted by Dr Kiwi
Hi Morb - I just jumped in here, but surely you MUST have a compatibility problem when you are 4 channels apart! Your Tx is on Channel 40 and your Rx is on Channel 44.

"Something is rotten in the state of Denmark!" (W. Shakespeare)

Cheers, Phil

Phil,

Not to sure what you mean..I tested the unit on the same channel as my Tx- 30......Futaba 6EXA.

I think it was Niceguy that got screwed.

Geof.
www.smoothair.rchomepage.com

my DSP4-SC makes a high pitched sound when you advance the throttle. I am running a GWS IPS A, with 10*4.7 prop, 2 Lipo 850 and two blue bird servos.
Is the normal?

Originally posted by geep
my DSP4-SC makes a high pitched sound when you advance the throttle. I am running a GWS IPS A, with 10*4.7 prop, 2 Lipo 850 and two blue bird servos.
Is the normal?

Yep..don't worry about it..it's right when you move the throttle up and goes away, right?

Geof.
www.smoothair.ca