The EZtrim® is an altitude hold unit for homebuilts.
The original EZ-Trim was build by Cliff Cady
The basic principle is simple. (As all great ideas
Build a print circuit board like the drawing, stack on the electronics.
Build a relay unit and connect a servo !! Done !!
The EZ-Trim, was sold in the old days for $300,-(EZ-Trim and relay
But before you get disappointed read this :
" I have decided to offer the unit's printed circuit board
files (EZ-Trim & Relay unit), the parts list, and the software
for download below.
This will let you make your own"
He doesn't sell the unit or the
board any more!
(We tried it !!)
You can download his free gift to the homebuilt society at:
So we had to do it ourselves !!
We have been able to rebuild this useful old gadget, fixed the
flaws in the drawing of the design. (There
will be if you use the info on the web)
So the CAS-COZY.NL EZtrim® was born.
All the parts from the very detailed part list of the originally
EZ-Trim, we had to buy in Europe. We were a little worried about
the PCB (Print Circuit Board),
do all the components fit on the board ?
We decided with the help of H.J. de gans electronics, to
build a new PCB according the electronics drawing.
This is our PCB board, with some funny details !!
The main components of the EZtrim®:
The basic stamp,
the brain of the module.
The pressure sensor
We build a new prototype for flight testing, we added all the panel
leds and switches in 1 box so only the 12v DC and the servo must
What did we change to the original EZ-Trim design?
|1 We changed the housing dimensions:120x80x55 mm (PCB Dimensions:110x70mm)
|2 We split the EZ-Trim in 2 parts. Computer-sensor module
and a button/led panel
|3 We have given the Computer sensor module 3 SubD9connectors.
|4 Safety feature.
|5 No additional relay box any more
|6 Additional software changes: safety altitude, response curves
Change 1 was needed to implement change 2.
Change 2 gives you the freedom, to position the EZtrim every
where and in every position in the plane you want. The button/led
panel is the visible part of the module
You build this your self (we can do it for you, but it's better
you do it !!)
You can arrange your own buttons and leds anywhere any place on
your panel. Which will give you more panel space.
Change 3 will provide you with SubD9 connectors for :
1 programming your basic stamp processor,
The RS232 connector of the basic stamp is brought outside and arranged
in such a away you can program it with a standard computer serial
cable M/F with your pc's com port.
You can download the all
basic stamp documentation in PDF and software
for FREE !!
2 Button/Led panel
(On/off switch, Up switch, Down switch,Reset switch, Up led,Down
3 Signal out/in connection
Up/down signal out to the servo relay and signal in connection of
the hat switch.
Change 4 Hat switch is able to override the EZtrim® signal,
because YOU are in control!!
Change 5 We will provide you with a relay which will do the
job of the relay box and has a smaller dimension (50x50x12mm)
Change 6 We implemented, some software changes and will do
more, if we are flying.
e.g. Minimum working altitude x ft above field level.
e.g. Servo response curve for the Strong pitch trim servo. (bench
Now you have to decide what you want.
The Dutch way :
You build your ez-trim according all info found on the internet.
It can be done(We did, so why can't you!) You do everything yourself
all info is free available, BUT PLEASE DON'T CONTACT US !!
PCB : Just the PCB, you order the
electronics yourself ! (70 euro, no shipping incl.)
Homebuilt kit: The
complete kit in a plastic container and all drawings.
We wish you good luck soldering according the drawings and programming
the basic stamp. (295 euro, no shipping incl.)
EZtrim®: Complete EZtrim®,
soldering done, programming done, bench tested*
*Bench testing is done with a Strong pitch trim servo. (410
euro, no shipping incl.)
Disclaimer: Purchaser assumes
all responsibility and liability for use of this product. Since
installation and attached equipment are out of our control, no warranty
It's experimental stuff,
if you don't like it, buy a TSO'd altitude hold autopilot
can't order direct !
we compile an order list and start soldering
when at least 5 units are on the list. So we can give you a
place on our ordering list !
(We don't give you a delivery date
!! But we promise to be as fast as possible !)
Just show us you are seriously interested by a donation of $10,- !! for our project.
This donation will keep "spammers" out of our mail box!
The pricing is done in euro's ! because the US $ is not stable enough for international
list is growing very rapidly!
Before sending this EZtrim® around the world, we have found a manufacturer
of a common canard type used servo available for flight testing the
This will take place in september/october
EZtrim news !!
Our test pilot has experienced some medical problems and had
to postpone the testing of the EZtrim. He will contact us if he is
able to fly again.
OOPS !! Maybe everything will be OK in a few months. But Not october
as we promised!
Sorry for that.
We warned you : Please don't hurry us !
This is a secondary CAS project and has lower priority as building our plane.
For people how have showed there interest in the
EZtrim and send us the donation,
we can do the following. We can
system and you test it yourself.
Or we send you the building kits and you start soldering.
(Nothing changed here, you were responsible for all your modification
to your experimental aircraft!!)
testing is done !! Works OK!!!
(Implementing software changes: min altitude , x
feet above field level.)