Raven Power Perch

[Adrian A]

Great. Now to order a magnetic switch from Adrian and then learn how to solder the wires to it :confused2: Thanks to his forum on the Featherweight site, I already know how to wire in the switch to the RRC2 (I think). The RRC2 has a battery + and - terminal block and then another terminal block for the switch. I hooked up the battery and found out which terminal on the switch block is powered when the battery is installed. Should be fairly straight forward.

Adrian (the other one with a very blue collar)

You can also just use 4-40 machine screws to connect wires to the magnetic switch. Put the screw in, wrap the wire around it, and tighten it down, similar to light switches and outlets with house wiring.

Edit: Just to be clear, this wiring discussion is applicable to the Featherweight magnetic switch. The Power Perch doesn't require any wiring other than connecting the deployment charges to the screw terminals.

 

[jd2cylman]

You can also just use 4-40 machine screws to connect wires to the magnetic switch. Put the screw in, wrap the wire around it, and tighten it down, similar to light switches and outlets with house wiring.

Probably the safer way for me to go. Most of my soldering experience is with 16ga and larger automotive wiring.
Adrian

 

[Brent]

You can also just use 4-40 machine screws to connect wires to the magnetic switch. Put the screw in, wrap the wire around it, and tighten it down, similar to light switches and outlets with house wiring.

I noticed the different magnets available. Do you determine small or large depending on airframe size and location in bay? Is the one that came with the 38mm bay the small?

 

[Adrian A]

I noticed the different magnets available. Do you determine small or large depending on airframe size and location in bay? Is the one that came with the 38mm bay the small?

I prefer the small magnets, which have a range of about 1.3". The larger magnets have a range of about 2.5", but their pull force of about 50 lbs makes them somewhat of a hassle.

 

[mikec]

Have you considered a lower-cost version of the Perch without the magnetic switch? This could just be the same board with the switch unpopulated. I've got several rocket/sled combos that would benefit from something like that; the sled ends up being too far inside the rocket to be easily triggered by the magnetic switch, plus I'm just cheap.

 

[Adrian A]

Have you considered a lower-cost version of the Perch without the magnetic switch? This could just be the same board with the switch unpopulated. I've got several rocket/sled combos that would benefit from something like that; the sled ends up being too far inside the rocket to be easily triggered by the magnetic switch, plus I'm just cheap.

I have, but replacing the on-board magnetic switch with extra switch terminals would only reduce the cost by less than $10. Making a board with a terminal block assembled on, plus providing hardware, packaging, etc. is most of the cost.

I like the idea of providing a setup where the users don't need to do any wiring other than just connecting the ematch leads.

Another way to put it is that just about any electronic board I can make and have assembled will cost about $20 before I put any features into it.

The triggering distance with the large magnet is about 2.6".

 

[atxcple]

that is it... i cant take it any more! i ordered my raven power perch today. :wink:

 

[mikec]

I have, but replacing the on-board magnetic switch with extra switch terminals would only reduce the cost by less than $10.

Thanks for the insight into the production realities. I just got my first Perch and I'll see how it goes with the magnet, but it's definitely the most convenient form factor one could imagine.

 

[Viperfixr]

Just got my Power Perch...love it, small, simple, effective, elegant. Only thing that immediately comes to mind to make it better would have been if it had come out sooner. This makes the Raven the best data recording altimeter for the money (maybe just the best?) AND the easiest av-bay setup, bar none. My Perch/Raven is going in a Competitor 3 that should fly on a KBA K750 next month .

Great job, Adrian! Featherweight Altimeters is bringing true innovation to the hobby. :clap:

 

[Adrian A]

Thanks for the insight into the production realities. I just got my first Perch and I'll see how it goes with the magnet, but it's definitely the most convenient form factor one could imagine.

Just got my Power Perch...love it, small, simple, effective, elegant. Only thing that immediately comes to mind to make it better would have been if it had come out sooner. This makes the Raven the best data recording altimeter for the money (maybe just the best?) AND the easiest av-bay setup, bar none. My Perch/Raven is going in a Competitor 3 that should fly on a KBA K750 next month .

Great job, Adrian! Featherweight Altimeters is bringing true innovation to the hobby. :clap:

Thanks, guys.

 

[JimJarvis50]

I thought since this thread has slowed down that it might be a good time to show my new altimeter bay and how I mounted my perches.

The first pic is of the bay assembled. The charge tubes on the left are a variation of my T-charge approach. The extra tube length lets the backpressure of the BP build up so that the charges will burn completely even in a full vacuum.

The bay will be mounted inside a solid airframe using socket screws tapped into the larger plywood bulkhead on the left.

The second pic is a video camera I'm going to try. This unit is voice activated, which I hope will let me turn it on when I assemble the bay and still have enough battery left for the flight. It has an RF remote as well, but it won't work through carbon fiber.

The third pic shows how the camera is mounted using its tripod mount.

Jim

 

[JimJarvis50]

So, now for the Ravens/Perches.

The first pic shows how I have them mounted on the board. One is upside down so that the switch is near the edge of the board for both perches. Adrian says that the Ravens work upside down. Hope he's right.

Here's how I secured the battery. This is set up so that the battery is very firmly pushed into its connection. Then, I used wood scraps to hold the battery level. The battery will be pinned in place in essentially all directions.

The third pic is the Raven board installed in the bay. The board gets held in place by the bulkheads on either end.

Jim

 

[JimJarvis50]

And finally, here's the Tiltometer board. The first pic just shows the mounting of the unit and the screw switches to make it work. The second pic shows the switches and the batteries around the back of the board. The final pic shows the installation of the board and shows how the batteries are pinned against the side of the bay. The central all-thread sort of snakes up through the middle.

Adrian, if you get your tilt design done, and if it can do apogee deployment, I could replace one of the Ravens. I don't think barometric deployment will work (I'm at the top of your range).

Jim

 

[atxcple]

So, now for the Ravens/Perches.

The first pic shows how I have them mounted on the board. One is upside down so that the switch is near the edge of the board for both perches. Adrian says that the Ravens work upside down. Hope he's right.

Here's how I secured the battery. This is set up so that the battery is very firmly pushed into its connection. Then, I used wood scraps to hold the battery level. The battery will be pinned in place in essentially all directions.

The third pic is the Raven board installed in the bay. The board gets held in place by the bulkheads on either end.

Jim

looks great sir. just one question... why do you have a channel jumped on your ravens?

 

[JimJarvis50]

looks great sir. just one question... why do you have a channel jumped on your ravens?

Would you believe that when I first tested the switch, I hung the units from a nail using that loop. Never got around to taking them off ....

Jim

 

[atxcple]

Would you believe that when I first tested the switch, I hung the units from a nail using that loop. Never got around to taking them off ....

Jim

um.....okay.:grin:

 

[troj]

And finally, here's the Tiltometer board. The first pic just shows the mounting of the unit and the screw switches to make it work.

Three switches?! What are all those for?

-Kevin

 

[Adrian A]

Adrian, if you get your tilt design done, and if it can do apogee deployment, I could replace one of the Ravens. I don't think barometric deployment will work (I'm at the top of your range).

Jim

Looks good, Jim. That camera looks interesting.

The Ravens do work just as well in as real flight with either end up. The only difference is that for testing, the simulated flight feature only works with the terminal block up, because it uses a built-in self test function of the accelerometer that only adds Gs in one direction. You can test it in the upside-down configuration manually, by giving the board a quick upward jerk and/or swing it around. The data recorded in the test from the upside-down one and the right-side-up one should be pretty similar.

I was definitely thinking of you when planning for the Featherweight tilt checker to have a gyro-based apogee deployment. But I think that gyro errors on my board will probably build up too much over the course of a 60-80 second flight to make it work better than accel-based or baro-based apogee detection. I plan to give that feature a try anyway and we'll see how it comes out. The Rocket Tiltometer with its built-in magnetometer should be more resistant to drift over longer flights than what I'm working on, so maybe there's an opportunity in there somewhere. When I get my RT to play with it I'll look into what the opportunities might be.

Have you tested the Ravens in your bell jar yet? With the special firmware you have, I was getting up to ~120kft before noise would trigger an apogee detection. If you need higher than that, there are a few options I can think of, but none of them great. I'm curious what you have in mind.

 

[JimJarvis50]

Three switches?! What are all those for?

-Kevin

I'm sure that the commercial descriptions of the tiltometer will be better than anything I can say, but the functions are to turn on the board, to connect the battery and to put the ignitor in the circuit. My belief is that switches 2 and 3 basically serve the function of taking the ignitor out of the circuit (i.e., shunting or opening the circuit to the igniter). In addition, the unit monitors the conditions across the switch such that you can't close the switch if the result would be firing the ignitor. My belief is that this is the safest possible way to arm a sustainer motor.

I was thinking about using a mag switch in the path to the ignitior to close the circuit to the igniter (and avoid having to poke holes in the airframe). Adrian talked me out of that.

Jim

 

[JimJarvis50]

Looks good, Jim. That camera looks interesting.

The Ravens do work just as well in as real flight with either end up. The only difference is that for testing, the simulated flight feature only works with the terminal block up, because it uses a built-in self test function of the accelerometer that only adds Gs in one direction. You can test it in the upside-down configuration manually, by giving the board a quick upward jerk and/or swing it around. The data recorded in the test from the upside-down one and the right-side-up one should be pretty similar.

I was definitely thinking of you when planning for the Featherweight tilt checker to have a gyro-based apogee deployment. But I think that gyro errors on my board will probably build up too much over the course of a 60-80 second flight to make it work better than accel-based or baro-based apogee detection. I plan to give that feature a try anyway and we'll see how it comes out. The Rocket Tiltometer with its built-in magnetometer should be more resistant to drift over longer flights than what I'm working on, so maybe there's an opportunity in there somewhere. When I get my RT to play with it I'll look into what the opportunities might be.

Have you tested the Ravens in your bell jar yet? With the special firmware you have, I was getting up to ~120kft before noise would trigger an apogee detection. If you need higher than that, there are a few options I can think of, but none of them great. I'm curious what you have in mind.

Well, we will see about the camera. It would be nice to find one of these things with the capability of an external switch. At least this one has a reasonable battery life.

Yeah, I suppose I should ask Frank about the apogee detection. I could be wrong, but I thought that was the main purpose of the original unit. But, the current unit doesn't have that capability so far as I know, or the capability to do something instead of not doing something.

The current simulation suggests 125K would be possible. With your enhancements, I could probably use either baro or accel and survive it if it gets anywhere near that altitude. I haven't done any testing on the units yet.

Jim

 

[troj]

I'm sure that the commercial descriptions of the tiltometer will be better than anything I can say, but the functions are to turn on the board, to connect the battery and to put the ignitor in the circuit. My belief is that switches 2 and 3 basically serve the function of taking the ignitor out of the circuit (i.e., shunting or opening the circuit to the igniter). In addition, the unit monitors the conditions across the switch such that you can't close the switch if the result would be firing the ignitor. My belief is that this is the safest possible way to arm a sustainer motor.

Phew. Seems like a lot of additional wiring and potential failure points.

-Kevin

 

[JimJarvis50]

Phew. Seems like a lot of additional wiring and potential failure points.

-Kevin

Yeah, I know what you mean. The good news is that once the screw switches are potted, they are very reliable. The device seems pretty sound to me, although I do manage to find things, but I think it will work for me. I think the safety features are important, but also, I can't afford to have the sustainer light if the angle is more than 15 degrees. That's just a lost rocket.

Jim

 

[atxcple]

my perch was in the mail yesterday... 3 days from order to door.. way to go Adrian thats customer service on yet another great product... already installed on my 3in sled

 

[Adrian A]

my perch was in the mail yesterday... 3 days from order to door.. way to go Adrian thats customer service on yet another great product... already installed on my 3in sled

Thanks, Shane. I can usually ship on the same day if an order comes in before 6:30 AM or so. Otherwise, I try to get them out the next business day. Flat-rate USPS priority mail shipping keeps things simple and pretty quick.

 

[troj]

Thanks, Shane. I can usually ship on the same day if an order comes in before 6:30 AM or so. Otherwise, I try to get them out the next business day. Flat-rate USPS priority mail shipping keeps things simple and pretty quick.

Mine didn't come in a flat-rate box...

-Kevin

 

[atxcple]

flew my raven / perch combo today, worked like a charm..

 

[StanO]

Ok..I'm ready to order my Power Perch due to the product and this great thread. I'm planning my avbay but would like to see the PP manual before I finalize the layout. I couldn't find the manual on the website. Is there a manual or even a rough draft available? Adrian?

StanO

 

[Adrian A]

Ok..I'm ready to order my Power Perch due to the product and this great thread. I'm planning my avbay but would like to see the PP manual before I finalize the layout. I couldn't find the manual on the website. Is there a manual or even a rough draft available? Adrian?

StanO

I think I wrote a draft but I'm surprised I hadn't posted it yet. I'll try to dig that up when I get home.

-Adrian

 

[Adrian A]

It was already posted to the website, but I had forgotten to publish the updates that included it. It's available now.

https://www.featherweightaltimeters.com/Av-Bay_Components.php

 

[StanO]

Thanks Adrian, just what I needed.

StanO