Thank you for the URLs. Smart electronic prints which I intend to test. Seems I
was sloppy mentioning apogee does not have them for sale.
As to accurate deployment with a rudimentary metal ball cage, being impossible:
according to following funny clips, it has been done.
Mechanical apogee detection switch (much too big a design probably):
https://www.youtube.com/watch?v=ldaHifNAxsg
Flight test with the contraption: https://www.youtube.com/watch?v=5wpmPgUQ0X8
I do not understand the construction detail, seeing a an electric relay mounted
also but I think it has no chip-like electronics inside, unless an Apogee
trajectory recording device was present in the rocket.
Since this principle can work, I found there is a cheap tiny tilt switch, the
Signalquest SQ-SEN-390 which has 2 microballs inside. Since it can take only
10 mA, it needs a DC-DC SSR to source current to an ematch from a 9 V battery.
Requires 2 batteries I was told, one for the sensor to activate the SSR and a 9
V one to light te match.
https://signalquest.com/product/components/sq-sen-390/
jd
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Ben Brockert
Sent: zaterdag 18 juli 2015 19:41
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: magnetic apogee sensor
There's a lot of them out there!
https://www.apogeerockets.com/Electronics_Payloads/Altimeters/PerfectFlite_StratoLogger_Altimeter?cPath=52_192&zenid=82e9eb46ba716a7b27c5ef85e148bd74
$59. No soldering. With screw terminals you attach a battery and up to two
igniters (up to a crazy 10A!) for deployment, one goes off at apogee and the
second goes off close to the ground, known as 'dual deployment'. Typically
either you just deploy the parachute at apogee for relatively low altitude
rockets, or you do a small drag device at apogee (a drogue or simply separating
the rocket into two pieces, attached by cord) and then a main parachute near
the ground.
Also logs apogee height and beeps it out.
$86:
https://www.apogeerockets.com/Electronics_Payloads/Dual-Deployment/EasyMini?zenid=82e9eb46ba716a7b27c5ef85e148bd74
Different manufacturer, same idea, still no soldering, and this one you can
directly plug into USB after the flight to download logged flight data.
There's no way a metal ball in a cage can give accurate apogee deployment for
any significant altitude, it's just not physically possible.
Ben
On Sat, Jul 18, 2015 at 1:11 PM, John Dom <johndom@xxxxxxxxx> wrote:
Ben Brockert wrote on 180715:
what's the use case that requires a magnetic apogee sensor? There are plenty
of barometric or accelerometer-based apogee sensors on the market, some
incredibly small, and they're quite reliable.
Plenty and on the market, I only need one! It need indeed not be a magnetic
apogee sensor circuit capable to fire a squib or drive a servomotor. I am
just exploring cheap reliable sensor actuator circuits on the market ready
for use.
Even Apogee does not have such and the item of Aerotech costs 150 USD and is
an RDAS dongle . So should you know better, please mention a sensr/PCB type &
company producing apogee actuators, NOT REQUIRING advanced (to me)
electronics circuitry design and tedious risky soldering jobs.
As far as I am slowly finding out, barometric, accelerometric or even such 3D
sensors record or transmit trajectory data like apogee which are only useful
for post-flight analysis. Giving nice graphs to point out when apogee
occurred in time, later on. But AFAIK, they are not actuators which can fire
the squib near apogee time. Most rocketeers I know, familiar with nineties
prints and code like RDAS report nice altimeter graphs. But their parachute
squib is fired by... a timer! Apogee time preset by trajectory simulation
software. Reliable?
So far the only cheap real time apogee actuators I came across are ingenious
metal ball or micro ball tilt sensors. No µprocessor fuss required. If they
are reliable I still have to find out next month or so.
jd
