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A project log for K-9

Raspberry Pi powered K-9 GUV with a NES controller style remote

andrew-billsAndrew Bills 03/13/2016 at 11:050 Comments

I received the motherboard spacer/mounts that I wanted to use for the project finally on Friday, which meant on Saturday I had to track down screws to fit seeing how these eBay special ones had inconsistent thread depths (which were too short for my 10mm screws). Fortunately I was able to get some from a RC Hobby store. While they are all hex that isn't a bad thing.

Today I cut the majority of the perspex & drilled holes for mounts for all the components I have for the main 'sandwich'. There are a couple of components that do not have screw holes or have components too close to their holes for me to screw down so not everything in the picture is 'attached', but even for the items that I didnt screw down entirely I still used the mounts for clearance and support. The items that didnt have screw holes I made a couple of holes to loosely zip tie the part down, which will stop it moving when the cables are also attached.

The standard mounts are only 10mm but the longer ones are 50mm. I put a hole in one piece so the touchscreen could be accessible from the top, but the bottom piece is there only for 'protecting' the wires from accidentally being pulled/touched/etc.

For the purposes of initially hooking everything up I've connected the relay to the 5v on the RPi instead of the battery, for now. This is just to let me check each part as I hook it up, so far I only had time to hook up the 8 channel relay (only 5 channels to be used) and the 9DOF (which I will need to programmatically cater for if I have mounted upside down, hopefully OK).Hooking this up with the USB for power lets me configure & update the Pi which I have switched with a RPi3. The upgrade means more power, more heat and a need to disable the inbuilt BTE because I need a serial interface to the XBEE. It also means inbuilt wifi though which is a bonus over a dongle.

I only have a USB breakout to attach which I will use to power the RPi through it's USB port instead of the GPIO as I learnt there is a mah limit through the pins. As soon as that arrives I will drill some mount holes to attach and hopefully have some more time to do some more hookup wiring.

I have decided on some 16Ah 22v Lipo batteries. I had also purchased some 'explosion' resistant metal protective containers for them after getting advice from the retailer they would fit. Unfortunately I discovered that while they did barely fit they also did slice open the battery leads. Lucky that it only cut one of the battery terminals & that the battery wasn't fully charged as I expect that would of done some serious damage to someone (with the 2 batteries in parallel I assume 32Ah @ 22.2v).

I've sent back the battery holders for a refund, but I also sent back the battery for a RMA & replacement seeing how it cant be safely used now + I did purchase the holders on their advice that it would be fine. Didn't really need the added cost & aggravation but hopefully that wont be a problem (even though it did add cost to courier back)

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