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My little NAV/OSD project - under construction


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I think the 20mm one I have will be comparable to the KX-151, both use the same SONY 1/3" CCD. I want it to be smaller so that it doesn't cause as much drag on my plane, is lighter, and fits more easily into cockpits. I am trying to get it so that the auto-WB is turned off so we don't get that ugly color changes in the video. I'll know how it works next week - am getting some samples to test and I'll post the results here.

Daniel

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I still waiting for some parts so I won't be posting any schematic until I've testing everything. There is no barometric sensor with these changes because to use a barometric sensor you will need a 14-bit ADC at least, which will mean a separate board altogether. This can be accomplished through the use of a OneWire interface to a Maxim/Dallas serial ADC but it will not be part of the original board.

As for change, there were some other changes which I posted about along the way since that schematics, mostly relating to the level shifting transistor. For the board that will be produced, it uses a different controller, a dsPIC30F4011 instead - and is a TQFP package. I have not posted anything on that improved design as yet. However, the PCB's are done and I believe the boards are being assembled at the factory (the reason being that it is all surface mounted with very fine traces). I should be getting my hands on them for testing next week or so. I am also expecting some parts to come in today. This is only a limited run - only 20 boards made, of which I will assemble 10 RTF OSDs (including BOB-4SG and GPS) for sale.

Daniel

Edited by Daniel Wee
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"As for the OSD package, I would buy it RTF"

Ditto.In a heartbeat.

One thing that i like and nobody else seems to care for is a RPM sensor capability.probably since most people fly airplanes maby it's not that usefull for them. I fly a heli.I like to know the eventual fluctuations of the main rotor.I suppose most OSD's are designed for airplane use so maby that's why except for the Inspire none of the others offer that feature.As far as i know.

minority member

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Daniel,

Same here. I'll take two RTFs when they're done.

I flew last week with my hand wired OSD. It was much too windy, and I ended up eventually crashing into a tree :lol: I only got to test the autopilot briefly, but it seemed to be turning in the correct direction. I'll post the video soon. The last frame is quite amusing, with a picture of the lipo ejecting from the plane, still connected ;) Everything survived in the end.

rimb05

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Hi rimb05,

Can't wait to see your video! Wow! Sorry about the crash though. BTW, I've got the code up to 4.1 which includes the ability to reset the home. Let me know if you want this code, I can post it but am trying to post with more significant changes. Right now it seems pretty stable. After I take a small break to get these boards done, I am going to add the map features.

Hi andrei,

What kind of RPM sensor do you have in mind? It may not be too hard to actually implement but it depends on the sensor.

Daniel

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I will buy one ARTF, without the BOB-4 if possible?

Already ordered the OSD module online with the 74mhz osc.

Hope the current sensing module is included :)

I cant help reading the post from the very first step over and over again, and everytime i do so i learn something new. This project is a real inspiration to all the beginners out there, like me, who used to look at OSD and in-flight AI as to a rocket science. Thanks for making it so much easy and clear.

time to sticky this thread i guess

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Hi andrei,

What kind of RPM sensor do you have in mind? It may not be too hard to actually implement but it depends on the sensor.

Daniel

Hi Daniel!

There are two types of RPM sensors that i know of;the optical and the magnets based(both from Eagletree).

I've tried both and i preffer the later.i'm using an Inspire OSD on my AP heli and the RPM sensor works very accurately.

Since i'm using higher voltages,5 and 6s configurations everything stays cool and i'm not as concerned with temperatures though it is nice to have the option of monitoring it too.I was somehow disappointed that the IF OSD had 2 temp sensors outlets and none for RPM's.

that being said i will use whatever sensor you can adapt.

Andrei

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Sorry guys, I was down with a fever (actually I am still sick) and at the same time some real life work came up that needed my attention. At this point, I'm just waiting for various shipments of parts to arrive, and most importantly for the PCBs to arrive from the factory.

Here's the state of affairs:-

1. Placing an order for 10-15 BOB-4SGs. They don't open on weekends.

2. Waiting for factory assembled DragonOSD's to arrive (better quality)

3. Waiting for some Farnell voltage regulators (they botched delivery)

4. And, also waiting for some really small CCD cameras to test.

So it's mostly waiting, and trying to get well at this time. I'll keep you guys posted as soon as something moves here.

Daniel

Edited by Daniel Wee
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Sorry guys, I was down with a fever (actually I am still sick) and at the same time some real life work came up that needed my attention. At this point, I'm just waiting for various shipments of parts to arrive, and most importantly for the PCBs to arrive from the factory.

Here's the state of affairs:-

1. Placing an order for 10-15 BOB-4SGs. They don't open on weekends.

2. Waiting for factory assembled DragonOSD's to arrive (better quality)

3. Waiting for some Farnell voltage regulators (they botched delivery)

Sorry to hear that Daniel,

Get well asap.

cheers,

m

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Okay, I know you guys are dying for some sort of news so I pulled out the soldered and finished up my prototype board for the new design (which has up to this point been purely theoretical). I did build the prototype board but had been waiting for Farnell to get me the parts and they finally got here today. Unfortunately I ordered the wrong package (was supposed to be to be TO-220 but turned out to be TO-223) but I managed to get everything soldered in and working. After some initial voltage checks without the MCU plugged in, I finally decided to give it a shot - seeing no reason for the board not to work and finding no evident errors thus far. 3.3V showing up where it should and 5V showing up where it should as well.

So, in goes the MCU, and then I soldered up the inter-connects to the BOB-4SG (only 5 now although the final will have 6. One of them is kinda optional.) And on this prototype board (which actually still uses the dsPIC30F4012 on a differently laid out board) has only one necessary jumper on the underside of the board so it looks quite a bit neater. Hooked up the ICD2 programmer and after some minutes I got a successful program - another good sign. Note that the programmer takes a bit longer at lower voltages than at higher ones.

So, altogether now - hooked up to a monitor and powered everything up - and - tada! Got text on screen, initialization message all showing up correctly! Cool. That means the SPI interface is working well. Then I made a cable for the GPS (this board uses a 5-pin connector instead of the 6-pin connector of the old board) and plugged the GPS module in. Powered it up again, got past the countdown and walah! We got GPS data. So in short - the new design works! Has fewer components, runs on 3.3V, but needs an additional regulator for the BOB-4SG which, weirdly, needs 5V even though everything on it runs at 3.3V logic levels. Oh well.

Actually, now that I think of it, this is a little miracle - I did this all in theory, re-laid the boards without much testing, soldered everything in, and hacked the wrong part, and everything worked on the first try, without any of the magic smoke escaping! Nice days do happen!

And now, some pictures for you all hungry people:-

DSC_6448.jpg

Above: The prototype board for the new reduced component and 3.3V design. Note that this is NOT what the final board looks like at all - this is purely prototype.

DSC_6449.jpg

Above: As you can see, I'm starting to use SMT components in my prototyping. In this case, I had to do it to get around my mis-ordered part problem.

DSC_6451.jpg

Above: Much cleaner under-side. For this prototype, I also used Phenolic Paper boards since they are so much easier to work with compared to FG, better for my health, and doesn't ruin my cutting tools so quickly. The downside is that they aren't as tough or stiff as the FG boards.

I'd be happy to take any questions if you have any.

Lastly, I heard from Mark that he is still ordering the parts to be sent to the PCB fab for them to assemble on to the boards. The boards are apparently done but we need to send them the parts for them to assemble it. The parts are coming from Mouser, and the fab is in Malaysia. When it's done, it gets sent to me in Singapore where I will program the MCU and test the boards, hook it up to the BOB-4SG (which should be here before the boards), and when everything is working (I intend to test each and every board), they will get sent to Mark for sale off the web-site. Well, that's the plan anyway.

And, thanks guys - I am feeling a bit better tonight. Was shivering with fever the last two nights. We have dengue going on around here and I think I'm clear of it. Today, incidentally, is also my birthday - 40 now! so there you have it.

Daniel

Edited by Daniel Wee
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Way to go Daniel! Now I really can't wait for the production boards!

Here's the update on my build. It's all up and running. As you can see, I've integrated everything on one board. There's even a header for the BOB-4H. Plug-and-play. The only issue is that the power traces are too thin and the motor sags with full throttle. I've modified the design and will try to fine tune the current sensor portion of the board.

post-6-1190687225_thumb.jpg

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The only issue is that the power traces are too thin and the motor sags with full throttle. I've modified the design and will try to fine tune the current sensor portion of the board.

docphi, are those traces around the current sensor you are talking about?

or are you using any other high power stuff somewhere on your board?

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docphi, are those traces around the current sensor you are talking about?

or are you using any other high power stuff somewhere on your board?

The small traces are around the current sensor. There's also a header to power a 5v camera and transmitter. However, the Dimension Engineering Vreg can handle the extra load.

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