NEW TO OTHERNET - Information Request (Technical Project)

S_H · October 17, 2020, 7:18pm

Hello,

I plan to make a project in hopes of winning a scholarship at a University. (Electrical Engineering)
And I want to be able to show proficiency in this area as it truly fascinates me.

The project is a general use / emergency station that will be housed in a small pelican case.
The rational being that if you are on a boat that has had its Systems fail / on the road in uncharted territory, you would be able to have this with you in a Pelican case ready for the worse. - it will have USB charging.

The product will have the following.

Foldable/ Retractable Satellite Receiver (Dreamcatcher + SDR + antenna Unknown for now)
Raspberry Pi - Computer
Both - Dreamcatcher and a USB SDR (Probably Nooelec)
Solar Charging
Kinetic Electrical Generator (Hand Crank)
Keyboard
Ball mouse

My question to the community is, would all of this be possible?
Would I run into any problems with anything you see stated above?
What secondary orbital satellite should I use for the SDR? (Possibly NOAA)
What SDR antenna should I have for said satellite?

PS. I’m confident in the power delivery side and such electronics, the whole satellite orientation is lacking in knowledge.

Thank you!!
S.H

Mark_Phillips · October 18, 2020, 2:11am

What would be the point of such a system? If you look around the net you’ll find many similar collections of hardware so you are not doing anything new.

Everything you list is receive only. How would one make others aware of ones emergency?

S_H · October 18, 2020, 4:41am

Hello,

I have stated that if you were to have other systems fail, this would be your only option.
(This Is Not A Product) - Again ive stated that the project is to prove competence in electrical engineering, for a chance to win a scholarship.
This isn’t something to resell or replicate, its more along the lines of a proof of concept.

The message feature on Skylark OS would be used to relay current GPS data and emergency for anyone around the world to see, i have seen someone use this system to send messages to other dreamcatchers.

Thanks

Mark_Phillips · October 18, 2020, 6:11pm

Electrical competence? OK. Go for it. And while you’re at it get a ham radio license. EE departments love that.

The message feature on Skylark is RX only. It can receive a message but not send one. You would still be stuck with the problem of alerting others to your troubles.

S_H · October 18, 2020, 6:39pm

I don’t understand all this hostility?

I am a University Grad in Technology hoping to restudy to Phd, Please do not belittle me.

Like I have stated, I am very new to this area and would like to learn it, as its something I am interested in.

You can send data to the APRS-IS servers that will update on Skylark messages.
TechMinds: has done a video on the subject.

Starting to realise that you are probably not capable of helping me, so please refrain from replying, as you have not answered any of my original questions, noor understood the concepts of the matter.

SH

Mark_Phillips · October 19, 2020, 6:19pm

Hostility? What? Not at all. Advice from someone that’s been there.

As a past teacher of Master level Computer Science students I can tell you that this sort of idea comes up all the time. I’m simply pointing out the flaws in your idea. You can be assured that the scholarship committee at the college will be well versed in the current state of SDR and your other proposed technologies. What sets you apart from the herd is the ability to overcome the committee’s arguments rather than overcome the technical issues.

As for the APRS-IS server, you can only send messages to that if you are A) a licensed ham radio operator (I did tell you to get a license) and B) if you have a transmit ability (you gotta put the message in there somehow).

Are we assuming that “techminds” is an expert in these matters simply because he has a poorly researched “look what I can do” youtube channel? He at least has a ham radio license that allows him to use the APRS-IS system (which he neglects to mention in his video)

A total system failure would be pretty difficult to recover from on a boat. However, a backup system such as you are describing would also not help much if you could not alert others to your issues. So how about you add a 30 meter band QRP HF transceiver to the mix so that you can put that message into the APRS-IS system? Many sailors have a ham radio license for no other reason than backup.

maxboysdad · October 22, 2020, 4:21pm

@S_H
Of course this would be possible. Pretty costly, but assuming you own the boat, the end justifies the means. Just a few questions, hoping to help you understand. Please don’t take this as insulting, YOU asked the questions. Mark has already given you some excellent guidance, but please consider these things: How large a Pelican™ case are you planning for? You have not stated your battery technology to be used, nor how the Raspberry Pi™ is to be implemented. What are the keyboard and mouse for? Will this be used with a laptop, or will the Raspberry Pi™ be used with a monitor (not included in your list).

S_H · October 22, 2020, 5:09pm

There are a lot of questions, I will answer them one by one.

Maybe the emergency part of the system I have spoken about is a little too complex for what I am hoping to create. I think the scope of the project should be limited to receive only, as this allows me to use familiar hardware, as I don’t know much about transmitting signals, so here is the new scope with all the details.

The scope is now just a redundant weather and general information index for Skylark software, if in need of up to date weather or general world news, you can use this “computer” to access this.

Another thing that I was thinking about recently is a gyroscopic auto aligner for the antenna, I have used something similar while working at university, we used a raspberry pi nano and a gyroscope that had a compass to firstly align with north, then cross reference the pitch of the antenna via a stepper motor to correctly focus on a satellite.

I think this could work if you had a database already in memory with relative satellite positions and earth (Longitude/Latitude) data. Again, I think this would also need a GPS for it to work correctly, so this is something to consider.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

The size of the pelican style case would be as follows – Reference (iM2200 STORM CASE)

Int. Length (mm)	381
Int. Width (mm)	267
Int. Depth (mm)	152
Int. Lid Depth (mm)	51
Ext. Length (mm)	411
Ext. Width (mm)	322
Ext. Depth (mm)	168

The battery is going to comprise of a 10Ah Battery made from 18650 cells running at 12v it will be connected to a BMS > Inverter (Solar Charging) > 5V step down to USB output.

1 = USB Power output (Predefined) – Raspberry Pi Computer

1 = USB Power output (Predefined) – Dreamcatcher v3.05

1 = 12v Power output ^ Inverter (Predefined) – laptop Screen Touch screen (Waterproof)

The Raspberry Pi computer will be used to interface with the Dreamcatcher device though a WI-FI module connected to the Raspberry Pi, the PI will then display the information of the skylark system to the monitor via HDMI.

Connected to the raspberry pi will be a USB keyboard mouse combo (similar to the old ThinkPad (nipple mouse) this will be covered in a rubber waterproof layer >

This will be used to interface with the Raspberry Pi computer. Running an OS (Android or Linux).

maxboysdad · October 22, 2020, 5:31pm

How much of this will be exposed to the weather when using it? I have spent a good deal of time at sea, and I know you will want to consider this. So far, it looks like you could operate for about two hours on battery as configured.

Syed · October 22, 2020, 5:45pm

You should take a look at the work that @Martin has done.

S_H · October 22, 2020, 5:49pm

I think the battery could be made bigger, but then the weight pay off could mean its tiresome to maneuver.
the ports of external charging and input for the solar panels will be covered by a rubber seal “plug” in my head i think this would be the best option, especially if it is a heavy duty plug with decent O-Rings.

but to answer your question, the parts that will be in direct contact would be the Monitor and the Keyboard, but bare in mind the monitor will be sealed with some kind of adhesive, and the keyboard covered in a rubber membrane.

One problem i can think of is if you damage the rubber membrane.

S_H · October 22, 2020, 5:51pm

That is exactly what i was thinking! just without the extender.

i think you could make it pretty compact.

Syed · October 22, 2020, 6:07pm

If you are starting this from scratch, you may not need the Arduino, as there are a few pins exposed on the Dreamcatcher which should allow you to control external hardware.

S_H · October 22, 2020, 6:09pm

Does the Dreamcatcher allow for reprogramming?> I saw that the I/0 pins.

Is there a Schematic anywhere that outlines the IO ?

Syed · October 22, 2020, 6:27pm

Dreamcatcher 3.05 SoC-GPIO Schematic.pdf (1.5 MB)

S_H · October 22, 2020, 6:31pm

Thank you, does the software allow you to add extra code?

Syed · October 22, 2020, 6:49pm

You have root access to Skylark, which is based on Buildroot, so you can do whatever you want. But it’s highly stripped down. Sorry, we don’t provide any support on custom development projects.

S_H · November 4, 2020, 10:52pm

So this is what I have been thinking so far.

Can anyone spot any obvious problems with this?

Thanks for all your help!

maxboysdad · November 5, 2020, 4:12pm

It looks good, but I question what do you need the “Digital Signal Video Decoder” for, as the RasPi has HDMI output? Just asking because it looks like you are pretty well covered otherwise. Jerry

S_H · November 5, 2020, 4:47pm

The Video Decoder is just the driver board for the HD monitor, I have decided not to go with a normal panel design, so the monitor comes in 2 parts.

The screen itself, and the driver board that handles the signal processing and has access to 12v rail voltage.

Thanks, I was toying with designs today to make sure it would actually fit, although very basic. this is what i was hoping the internals to look like.