RavenPlus All-in-one Altimeter

[Adrian A]

"I'm still in favor of having a mechanical (or solid-state) switch that opens up a HPR motor ignition circuit that's independent from everything else, so that you can turn on everything else at the pad and confirm from your beeping altimeter that all the deployment charges are ready to go before you enable that airstart ignitor."

YES!!!
Totally agree... you really need something that disconnects and shunts the pyro's.
Especially when dealing with HEI motors....that are built and installed in advance.
I wouldn't think of doing anything else....

Feel free to read and contribute to this thread on airstart safety for a good discussion on this if you haven't already seen it.

Now just wish today's altimeters would really support motor ignition....
Some don't arm if you have a disconnected pyro....you can't delay arming the motor till the last checklist item.

The Raven doesn't have a problem with that.

Some continue to do their continuity ping into motor ignition circuits.

The raven has 266 kOhms in series with the continuity check. Only 10s of micro-amps go through the ignitor, putting less than 1 in 100,000 the power needed to fire it.

Most don't have enough channels to light motors and still handle deployments....man I'd love to have 5 or 6 channels so we can do an air-start or two and still do dual-deploy with backup chrages off of a single altimeter.... (hint Adrian...can we have an Albatross???)

With 4 outputs, you can do stage separation, motor ignition, apogee, and main deployments all in one, and use a separate altimeter with its own power supply for a true redundancy on the deployments. If you don't have space for full redundancy, you can off-load the staging charge to the booster's Raven and then you have a freed up output for a backup apogee or main. That's how I set up my high-altitude staged flights, with a medium-altitude deployment in case the altitude keeps my apogee charge from working.

For the Raven (and the RavenPlus), adding another output channel or two would bust the design on multiple fronts, including pin count, A/D inputs, and program memory.

Things get really interesting when you use "ignition controllers" to light the motors on command from the altimeter. These can fire on WAY less current than an igniter and can be incompatible with the continuity checks.

Why use "ignition controllers" you ask....because many altimeters can't fire multiple pyro's at the same time for clustered airstarts and/or there is a need to span the drogue bay with thin, breakable wires that won't support the current needed to light multiple motors... So we put a small "amplifier" at the head of the motor(s) that provides the current (from a local battery) when signalled from the altimeter.

I like to use simple pull-apart connectors to span across separating parts of the rocket. And you'd be surprised how much current tiny wires can handle if you're not worried about temperature rise.

 

[lmt56]

Any chance you could include a motor analysis function on it?
Could be a good selling point for the EX people.
Looks to me like the Arts II's may be a thing of the past.

 

[GaryT]

This is what I'd like to see:

• A Raven that has all the same recording capability's as the original/Current Model.
  
• Same or a tad bigger in size.
  
• No deployment of any kind.
  
• Has an integrated battery.
  
• No magnetic switch just an on/off push button switch.
  
• A mounting plate that can be placed on all your Av-Bay sleds where the unit could snap into and be moved effortlessly from one rocket to the next.
  
• Enough memory to contain at least 5 flights before needing to down load.

The reason for this is so people who already have Av-Bays and altimeters (Not Recording) Can just add this to their existing Av-Bays without having to buy all new altimeters.

By eliminating allot of the extras and concentrating on nothing but the recording aspects I would assume it could be manufactured pretty cheaply?

 

[troj]

By eliminating allot of the extras and concentrating on nothing but the recording aspects I would assume it could be manufactured pretty cheaply?

I'll confess, I don't understand the desire for a recording-only altimeter. I also suspect it wouldn't reduce the cost by as much as you'd like it to.

-Kevin

 

[GaryT]

K:
The reason for this is so people who already have Av-Bays and altimeters (Not Recording) Can just add this to their existing Av-Bays without having to buy all new altimeters.

Without really knowing I kind of think the price wouldn't drop dramatically either but Adrian would know much better.

I agree it wouldn't be a fly off the shelves item but I do think it has its nitch, Probably just me thinking out loud cause I want one lol.

 

[troj]

I'll admit, the need doesn't make sense to me -- rather than install yet another altimeter, just for recording, I'd be more inclined to buy one and use it to not only record, but also to do events.

But, that's my preference, and there's absolutely nothing wrong with someone taking an altimeter along for a ride for purely recording purposes.

Cool thing about the hobby -- there's rarely only one "right" way!

-Kevin

 

[patelldp]

I believe Gary may be on to something for a very specific market.

Basically people that enjoy the reliability of baro units (MAWD, RRC2, and the like), have the rocket all set up, but desire a simple way of collecting data without redoing their deployment scheme.

My personal "mantra" is that if an electronics unit is in the rocket, I always give it the chance to save itself. Meaning, it needs charges hooked up to it. I lost an AltAcc 2C back in the day due to a lawn dart where I only had the altimeter in for data collection. A little grease on the delay and I snapped the AltAcc.

So while I would not purchase a record only unit, there may be a small market, especially if their is a cost savings (which I foresee to be minimal).

 

[Adrian A]

This is what I'd like to see:

• A Raven that has all the same recording capability's as the original/Current Model.
  
• Same or a tad bigger in size.
  
• No deployment of any kind.
  
• Has an integrated battery.
  
• No magnetic switch just an on/off push button switch.
  
• A mounting plate that can be placed on all your Av-Bay sleds where the unit could snap into and be moved effortlessly from one rocket to the next.
  
• Enough memory to contain at least 5 flights before needing to down load.

The reason for this is so people who already have Av-Bays and altimeters (Not Recording) Can just add this to their existing Av-Bays without having to buy all new altimeters.

By eliminating allot of the extras and concentrating on nothing but the recording aspects I would assume it could be manufactured pretty cheaply?

The deployment outputs add about 10% of the total cost.

I'm curious about what you have in mind for the mounting plate. How would the altimeter be attached to it? How is it different from putting appropriate mounting holes in multiple sleds?

Thanks.

 

[GaryT]

The deployment outputs add about 10% of the total cost.

I'm curious about what you have in mind for the mounting plate. How would the altimeter be attached to it? How is it different from putting appropriate mounting holes in multiple sleds?

Thanks.

A:
A mounting plate was just for simplicity, That would have to be researched, I didn't have anything in particular in mind but just the idea, The mounting holes would work but I was thinking a tooless design.

At 10% less I guess it really wouldn't be practical.

 

[troj]

A mounting plate was just for simplicity, That would have to be researched, I didn't have anything in particular in mind but just the idea, The mounting holes would work but I was thinking a tooless design.

I think the best route for this would be one of the Raven AvBays, with a receiver built into the rocket -- just drop the assembled av-bay in to the receiver, and be done with it.

-Kevin

 

[JDcluster]

All want is: it to have a simple 2 wire terminal for a switch of my choosing whether it be twist 2 wires together or not..
Still waiting for the motor analysis..:dark:


JD

 

[H_Rocket]

I'm curious about what you have in mind for the mounting plate. How would the altimeter be attached to it? How is it different from putting appropriate mounting holes in multiple sleds?

Gary and I e-mailed on this one. Having thought a bit more on the design, what I would like to see is a matched pair of passive back planes where one would mount to the sled, and the other could be a place to mount the electronics. I would leverage something like Ampmodu .050 board to board connectors. Then to move the electronics from sled to sled, you just unlatch the daughter board and move it.

One step simpler would be to have the altimeter mount with a board to board connector to a passive back plane.

One thing (and there are not many) GT and I agree on is that hooking and unhooking wires from screw terminal blocks really rots. If I could install an altimeter w/o monkeying with the terminal blocks, I would consider it a major bonus.

 

[troj]

Gary and I e-mailed on this one. Having thought a bit more on the design, what I would like to see is a matched pair of passive back planes where one would mount to the sled, and the other could be a place to mount the electronics. I would leverage something like Ampmodu .050 board to board connectors. Then to move the electronics from sled to sled, you just unlatch the daughter board and move it.

One step simpler would be to have the altimeter mount with a board to board connector to a passive back plane.

One thing (and there are not many) GT and I agree on is that hooking and unhooking wires from screw terminal blocks really rots. If I could install an altimeter w/o monkeying with the terminal blocks, I would consider it a major bonus.

So your thought is a mounting plate that stays in the rocket, and the altimeter just latches and unlatches?

Interesting idea.

If designed such that tools aren't required to install/remove the altimeter, it'd be slick. But, to me, if it still required tools, then I haven't gained anything.

Cost would also matter -- if I could do it for, say, $10 or $15 per altimeter mount, then I'd go for it. Make it more than that, and I'll just stick with wire terminals.

-Kevin

 

[GaryT]

Didn't I already say that.


A mounting plate that can be placed on all your Av-Bay sleds where the unit could snap into and be moved effortlessly from one rocket to the next.

 

[H_Rocket]

In the idea I was thinking, just a simple pin connector fro the board to board mounting with some sort of cam-action retainer.

I would have the base plate on the sled and a daughter board where the Altimeter would mount. The screw terminal wiring would go to the base plate and the altimeter would mount on the daughter board. Pres the daughter board on to the base plate and it either uses a cam latch or some other positive retention. The daughter could be designed to be altimeter specific or universal. Of course this adds volume and bulk thereby kind of does away with the small size advantage of devices like the Raven.

 

[troj]

Didn't I already say that.


A mounting plate that can be placed on all your Av-Bay sleds where the unit could snap into and be moved effortlessly from one rocket to the next.

As much as anything, I was restating to clarify and make sure I understood it. I didn't get your description, and after reading Al's post, I thought I did.

Interesting idea. Very interesting.

For anything other than minimum diameter/pure performance, I think it's a pretty slick idea.

-Kevin

 

[Adrian A]

I'll look to see if there are plug-in connectors that could be installed in place of the screw terminals as an option. Then people could use wingnuts or wing screws for tool-free board installation.

 

[troj]

I'll look to see if there are plug-in connectors that could be installed in place of the screw terminals as an option. Then people could use wingnuts or wing screws for tool-free board installation.

My opinion...to really benefit, I'd prefer no screws/nuts, or I haven't gained anything. Others may disagree.

What about a board a standard Raven can be mounted to which has the ability to be snapped into the receiver?

That way, the altimeter is standard and can be used in standard mounting, too. Also saves you from stocking two variations of the altimeter.

 

[GaryT]

How about something similar to how memory is added to your computer? The board/Altimeter could be mounted horizontal rather than vertical, There are probably better ways to lock it into position that way as well.

All the other components can be hard wired to the female side of the connector, Battery, Switch, E-Matches etc.

 

[H_Rocket]

The kind of connectors used are SODIMM installs are designed for board edge to slot and might work. I need to look at some specs. The only thing is the altimeter would be mounted on edge perpendicular to the sled. The idea I have is a stacking board connection.
Here is a sketchup of one idea.

 

[GaryT]

Al:
Did you even read my post????

The board/Altimeter could be mounted horizontal rather than vertical, There are probably better ways to lock it into position that way as well.

 

[GaryT]

The kind of connectors used are SODIMM installs are designed for board edge to slot and might work. I need to look at some specs. The only thing is the altimeter would be mounted on edge perpendicular to the sled. The idea I have is a stacking board connection.
Here is a sketchup of one idea.

In your schematic that design still requires wiring which defeats the whole purpose of the Idea, I'm talking Plug and Play.

 

[H_Rocket]

What you are saying is redesign the altimeter to not require any wiring. I'm looking at a way to capitalize on existing devices. I want to leave a passive interface that I can mount any altimeter made onto and then move it from sled to sled. Yes there is wiring from the altimeter to the carrier and from the back plane to the airframe. Once set, they never need to be touched again. I want to eliminate fiddling with the wires and with the standoffs.


And why would I read your posts? That's just boring.

 

[Adrian A]

My opinion...to really benefit, I'd prefer no screws/nuts, or I haven't gained anything. Others may disagree.

What about a board a standard Raven can be mounted to which has the ability to be snapped into the receiver?

That way, the altimeter is standard and can be used in standard mounting, too. Also saves you from stocking two variations of the altimeter.

Hmmm. I'm warming up to that idea. There could be a carrier board that has the magnetic switch, and it could snap into a base board that has the battery connector and pyro terminals. The RavenPlus could snap into the base directly. Then the user could have one base per rocket that could be used with a Raven or RavenPlus. Or maybe I would just make the carrier for the Raven and skip the RavenPlus. Interesting options I hadn't thought of before. I'm not sure yet what would provide the most value. The RavenPlus that is self-contained without a base unit is pretty much done, though. The board for rev-2 of the prototype should be done this week.

 

[troj]

Al is kinda on the same thought as me, though he shows wires, which I agree with Gary, we want to avoid!

Let me start with some terminology I'm using, to help all this make sense.

"Receiver Board" would be an inexpensive board (basically connectors and physical restraint mechanism) that is permanently mounted in a rocket.

"Adapter Board" is a board that a Raven is mounted to, enabling it to be plugged into a Receiver Board.

"Raven" would be a standard Raven.

My thought is that the adapter board would have L-shaped pins on it, similar to what the Raven Av-Bays have. You slide the Raven over those, tighten down the screws and put another screw between the Raven and the adapter board, creating the module.

That module then has a connector on the bottom of it, and when the adapter board is snapped into the receiver board, it not only secures things in place, but it also makes the connection from the Raven to the terminal blocks in the rocket -- there are terminal blocks on the receiver, and those wires, after installation, never have to be touched, if so desired.

The adapter board could easily contain the magnetic switch (for those who want them), as well as a place to install an optional LiPo battery similar to what the RavenPlus uses. The ideal would be for the receiver board to also have the ability to accept power from a 9V battery to power things, for those who prefer that route.

I forsee two versions of the adapter board -- one with the magnetic switch, and one without. The receiver board would have a connector for an external switch. If you prefer an adapter board with a magnetic switch, you put a short wire jumper across the receiver board switch connector, and just leave it there. Receiver boards without the magnetic switch would just have a jumper soldered across the proper terminals on the board so that an external switch is used, instead.

The adapter board could possibly have a connector and circuitry to allow for charging of a LiPo.

Trying to think of flexibility, while reducing variation of the devices -- one standard Raven, one standard receiver board, regardless of configuration. The only variation would be in the adapter board -- whether it has a jumper soldered to it, or it has a magnetic switch soldered on.

The receiver board has to be standard and fairly simple, to keep cost down, as those using this system would need to buy several of them.

-Kevin

 

[H_Rocket]

Yes, if we could avoid wires altogether that would be cool. My thought was along making a snap in board that I can use with other altimeters.

 

[Rocketjunkie]

Why all the complexity?

E-matches are single use. You will have to wire them somewhere.
Screw terminals are reliable and vibration resistant.
I spend way too much time tracking down electrical failures in panels attached to vibrating machinery at work. Snap on connections and plugs are always the first things to look for when intermittent problems arise.

I wire my e-matches directly to the altimeter, new wires each flight. All my rockets have a common sled carrier. I move the whole sled from one rocket to another.

 

[troj]

Why all the complexity?

E-matches are single use. You will have to wire them somewhere.
Screw terminals are reliable and vibration resistant.
I spend way too much time tracking down electrical failures in panels attached to vibrating machinery at work. Snap on connections and plugs are always the first things to look for when intermittent problems arise.

I wire my e-matches directly to the altimeter, new wires each flight. All my rockets have a common sled carrier. I move the whole sled from one rocket to another.

For some designs, there are terminal blocks placed on the outside of av bay, which means that when the altimeter is moved, the wires have to be connected not only to the altimeter, but also then to the terminal blocks at the other end.

The goal here is to create a more modular sled that can easily be moved, and minimize the number of reconnections that have to be made.

All that said, your point about connection failures is indeed a valid one.

-Kevin

 

[H_Rocket]

If I wanted complete vibration resistance, I would go with barrel terminals and solder the e-match leads directly to the board. Not practical by any stretch of imagination so I want something easy. My main beef with screw terminals is that I really dislike the torque they put on the board when tightening them down (especially in the 2 position blocks). That and I can never find the right jeweler's screwdriver...

 

[Adrian A]

The mini-maTch connectors are a new variety that is compact and has some good features for vibration resistance, but the rated current per contact is pretty low. I'm not sure how available the board-to-board variety is.