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A project log for TestLogger Collector

Datalogging device for designed RC car racing

Jussi LuopajärviJussi Luopajärvi 12/17/2018 at 21:350 Comments

A bit of brake from updating as I have had some work and holiday trips. After the first version made completely by myself which had fairly limited amount of inputs, I decided to go for the full version with my own design. 

Base guideline for the design was same inputs as I had for PYB shield with much smaller area covered. Usually the height isn't a problem but area used is a big issue. I decided to to with 2 PCBs stacked and connected to together with three board-to-board connectors.

The goals were achieved with a big but. It was almost half of the size compared to PYB shield version and it had the same connectors. Also the weight was surprisingly low as you can see from the picture below. It was almost 10 grams lighter than PYB shield version. The problem was related to connecting the two PCBs together and using the device on car which jumps and get's massive hits. The boards were not sticking together and then everything fails. 

I also noticed few other issues like routing and component placement. I placed too many components on the upper board so I needed more pins to connect the two boards which again took extra space from the board.

New try with V2

I did learn my lesson from this one and I designed V2 with solderable headers and went first time for the four layer PCB as it seems that it's correct way to do these things. Layout was also improved. I changed backup capacitor, LEDs and microSD connector to lower board. This made the upper board smaller which provided more room on the lower board and pins connecting the boards went from 30 to 16.

My layout and routing skills are still below zero and pretty sure I need ask someone to do a final decision for me who knows what he/she is doing as I'm not...

PCB's are on their way, so start of next year I should have a new version to test. This time I used https://jlcpcb.com to order the PCBs as prices for their four layer boards were quite good. 10 pieces of one board costs 13 USD plus shipping, so that's not bad. Let's see how is the quality of the boards.

That's it for this time. Maybe I will write something about the sensors during Christmas break as for example damper potentiometers have gone through quite many iterations already and now I have found clean and light weight method to do it...

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