Electronics > Mechanical & Automation Engineering

Micro Mouse Robot

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alanb:

--- Quote from: Doctorandus_P on February 15, 2019, 12:21:19 am ---Handsoldering the vl53l0 without microscope & experience will be quite a challenge indeed.
But if you're not upto that chalenge you can easily buy them on breakout boards with breadboard friendly 0.1" headers.
It's up to you where you want to get them from  8)

https://www.adafruit.com/product/3317
https://eu.mouser.com/Search/Refine?N=1323043&Keyword=VL53L0
https://www.aliexpress.com/wholesale?SearchText=vl53l0xv2

--- End quote ---

I'm going to use cheap breakout boards from Ebay together with cheap motors with encoders for the intial prototype. I'll leave the soldering of the vl5310's until the second version. The first version will be a development test bed, it won't be entering any competitions so size, weight and speed at this stage don't matter.   

Mysion:
Alanb sounds like a good plan! You'll have to use a library to interface with them. The data sheet's don't expose the inner workings and most of the library's come from reverse engineering ST's official C library for the sensors. Bit of a bummer but not too bad.

I spent some time looking around and found an IR sensor I like on digikey.  https://www.digikey.com/products/en?keywords=336-5135-ND
They look like they should be better than the VNCL4020's I've used before. More importantly they allow for changing there I2C address same as the VL53. This means no dam I2C splitter chip.

It's a simple enough schematic and it didn't take me long. To disable the IR sensors I'm simply tying a N channel MOSFET to the logic power line. This way I can disable all some of them and reprogram the I2C address.

Mysion:
I went though a few revisions on the sensor daughter board but I finally made one I liked. Here's the finished PCB design and a 3D render straight from diptrace.





The small mosfet is to turn off the IR module so that I can change the I2C address at start up. If all sensors power up with the default address they will create collision on the communication bus. This way I can keep all but one powered down. This way I can change the I2C address one at a time.

I've been working on the PCB for the power supply test and that should be done soon and ready to send off.

Mysion:
With the sensor step file exported from dip trace I mocked it up on the cad model.



With this many sensors I practically have a primitive LIDAR system! Not sure I need this many but why not!

The main schematic for the main board is almost done. I was worried the circuitry wouldn't fit but it will. Might just be a bit snug.

Mysion:
I finished the layout for the power supply test PCB. It's drop 8.4V to 6V and 3.3V. For the motors and microcontroler respectively. I think it looks good for my first SMPS. I used a 4 layer board and kept every thing close together.



I also got my first bit of code running on my STM32F070RB dev board! A simple freertos example that passes button input to another thread blinking an LED. It's a start!

I'm using atollic as my IDE. I'm still getting used to it but it seems good so far.

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