Magnetic Apogee Detectors

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bobdog

Active Member
Three magnetic apogee detectors for sale: 1 - Version 2; 1- Version 3; and 1 - Version 4 (sold).
Version 2 & 3 have flown two or three times. Version 4 is unused. Don't remember what the differences between Version 2 & 3 are, but Version 4 has a built-in LED.
All set up for flying in Montana. Easily modified by changing a resistor - instructions can be supplied.

Prices: Version 2 & 3 = $15.00 each with free CONSUS shipping SOLD Version 4 =$20.00 with free CONSUS shipping SOLD

Payment: PayPal F&F

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BuiltFromTrash

Well-Known Member
I assume when apogee is detected it will send current to the terminal blocks?

Also, what are the dimensions?

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bobdog

Active Member
Yes, current for the ejection charge is sent to two terminals on the terminal block at apogee. The other two terminals on the block are for an on/off switch.

I will have the dimensions for you this afternoon.

BuiltFromTrash

Well-Known Member
Another quick question, what is CONSUS shipping?

Bat-mite

Rocketeer in MD
Another quick question, what is CONSUS shipping?
I think he means CONUS - CONtinental United States, i.e., the lower 48.

bobdog

Active Member
The dimensions are: 4 3/8"L x 9/16" W x 3/8" H. The unit, itself, will fit in an Estes BT-20 tube. but you will need room for your battery of choice.

CONSUS is Continental United States (lower 48) as explained by Bat-mite above.

ksaves2

I've flown these devices extensively and they work. The versions I have I believe are Version 4 as they have the LED. The green LED acts as a continuity indicator on mine. One can test with an LED on the terminals. Tip the device over and the LED at the
terminals will light (indicating current is being sent) and the green LED will go out. Aerocon sold these and they were designed by Robert Galejs who I believe has a Phd by now. Do not attempt using homemade ematches unless you are sure they have the same specs as commercial matches. I tried and dorked my first unit. I tracked down Dr. Galejs and he very nicely accepted mine and fixed it. (I dropped 15 or 20 bucks in unsolicited) So only use commercial ematches.

Also, once activated, DO NOT TIP OVER! I know that sounds simplistic but it's easy to lose one's track of mind at a launch event if something happens and you have to take a rocket off the rail. I've never had that happen to me as I treat the device with the utmost respect. Also I recommend testing with an LED or christmas light on the ematch terminal because the angle of deployment is different N-S, E-W so you get an idea of what to expect.
One wouldn't want the rocket going off at an angle because it could lead to a high-speed deployment coming over the top.

I mount a lockswitch on the bulkhead of an ASP WAC Corporal, put the rocket on the rail, raise the nosecone/coupler, turnon the lockswitch, confirm the green LED is on and lower the nosecone/coupler on the bodytube. Insert igniter and fly.

The ASP (large WAC) has the nosecone mounted on a coupler that has a bulkhead that slides into the bodytube. The nosecone shoulder just needs to be trimmed a bit and that coupler is a perfect ebay for this MAD unit. Use four screws to hold the coupler to the nosecone shoulder and good to go. Only thing one needs to buy is a locking toggle switch! It's a real sweet rocket for this device. With the Jolly Logic Chute release can use some pretty nice
H motors to fly.

As a kit, I think they originally went for 19.95 and went up to 29.95 over time. There was an assembled version for more. The OP's price is very reasonable and with care a person can have fun with them. Check out the ASP
38mm WAC if one would like a shoe-in kit. http://www.asp-rocketry.com/ecommer...ge-29-38-mm-Version-.cfm?item_id=631&parent=8

Punch a hole in the coupler near the level where the green LED resides so one can see it's on.

The only other in production MAD device is the Zeptomag that is pretty feature filled: https://www.tindie.com/products/ZeptoBit/zeptomag/

I have a couple. Can turn it on and since it is activated by an accelerometer, it won't fire with a simple tip over unless it's in flight. Kurt

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H_Rocket

Death by Powerpoint
How much tip does it require to detect? I'm thinking a staging interlock...

ksaves2

How much tip does it require to detect? I'm thinking a staging interlock...
Forget it. It's for recovery deployment only. It depends on the latitude one is at and the direction the rocket is pointing. In some orientations, it's pointed just below the horizon so it wouldn't be a consistently safe device to use as a staging interlock.
It could intervene too late. They're really simple devices and the circuitry is really rudimentary. I don't think the FETS can take much current either as I mentioned I dorked my first one. You would have to get an intermediary circuit amplifier to control the lockout but like I said, the circuit will not activate unless it's way off vertical in some orientations.

I think the only thing out there for fully definitive control is the Easy and Tele Mega with the solid state accelerometers and gyros. Kurt Savegnago

dixontj93060

Well-Known Member
Forget it. It's for recovery deployment only. It depends on the latitude one is at and the direction the rocket is pointing. In some orientations, it's pointed just below the horizon so it wouldn't be a consistently safe device to use as a staging interlock.
It could intervene too late. They're really simple devices and the circuitry is really rudimentary. I don't think the FETS can take much current either as I mentioned I dorked my first one. You would have to get an intermediary circuit amplifier to control the lockout but like I said, the circuit will not activate unless it's way off vertical in some orientations.

I think the only thing out there for fully definitive control is the Easy and Tele Mega with the solid state accelerometers and gyros. Kurt Savegnago
I'm not so sure... The Zeptomag has an angle set feature so you can pick the tilt angle so it is not as extreme as you state. But yes, you do have to have some negative logic in there to disconnect the staging circuit. My design uses a simple latching relay.