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Modifications after some tests

A project log for PipeCam: Low-Cost Autonomous Underwater Camera

Low cost autonomous underwater camera for long term deployments and exploration

fred-fourieFred Fourie 03/10/2018 at 18:090 Comments

Four main things have become clear from the first set of tests.

1. Power will need to be increase/managed

The sealed lead acid battery is a cheap but bulky solution. The 12V 2.4Ah battery costs about R130. I have the space to easily double up on that battery, so that gives me 12V ~4.8Ah for about R260. BUT I can get a power bank with a similar form factor at 5V with 10 Ah of capacity at a prices of ~R270 PLUS I don't need the DC regulator board. So it's a bit of a no-brainer. I'll be swapping over to a lithium ion power bank.

I have also decided to change from the Raspberry Pi 3, to the Pi Zero W to clamp down on the overhead. This means a loss of 4xUSB slots, which I will need to recover with an external USB hub which may mean a little bit of a extra power penalty. 

2. Storage space needs to be increased

Good video chows space. No way around it. I need to beef up my storage capacity to match the battery endurance. Time-lapse operations are a lot easier on storage, but video needs to be of good to maximum quality to make it worth it. My preference so far is the SanDisk Cruzer Blade flash drives, because of the small size and ease with which it can be removed from the Raspberry Pi after operations. I also like that they come in way-out colours, which make them easy to ID.

3. Housing need further tests

A minor/slow leak was found on the housing during the second test. Luckily the internals were protected by the internal mounting which lifts the electronics off the bottom. I have my suspicions on what is causing the leak. 

I handed over the housing over to Dylan (the mechanical wiz and partner in the project) for testing and he will be building the a new housing while I focus on some software and electronics. 

 4. The Raspberry Pi V2 module is NOT robust

Part of the reason why I'll be looking at the electronics: Looks like I fried a V2 camera module, even after taking care to handle it as little as possible. I will need to look into having a case 3D printed. The board itself is notoriously prone to static and has a rather fiddly ribbon cable. The board sports a crypto-chip to discourage cheap clones, which I can forgive to an extent. Still- for ~R400 it is still hard to beat. It's strike one for the module. I've had to order a new module, hopefully I can refine my design so that there is even less interaction with the board and it can prove that it's still the best choice for the project.

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