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Category Archives: Hardware
Pinion interfering with the tire
When I applied power to the motors on Zeetah VI (ZVI) for the first time, the motors seemed to struggle and the PWM value to get the wheels to rotate seemed higher than usual. Since this was my first four … Continue reading
Posted in Hardware, Micromouse
Tagged file, friction, interefere, interference, pinion, sand, tire
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Comparing the ADXRS610 and ADXRS642 gyros
Analog Devices recently release new vibration rejection gyros which seemed a perfect fit for use on a micromouse. Since I was using the ADXRS610 on Zeetah V, I temporarily mounted an ADXRS642 to ZV to compare the two.
Soldering the gyro
Finally, a way to solder the Analog Devices ADXRS610 gyro… The last time we attached a gyro, we overheated the board and the board delaminated. This time, we use a skillet and avoided that problem.
Painting the floor
Once the panels dried out, it was time to paint them.
Making the floor
Now that I had the layout, the next step was to cut and drill the plywood. While there are many techniques for doing this, I ended up getting help from a friend who has access to water jet cutters to … Continue reading
Designing a maze floor
Given standard sizes for plywood, here is a pattern I used to make a maze floor.
How many walls do you need for a square maze?
At the Japanese contest, Peter said there is a closed form solution for the maximum number of walls a legal micromouse maze can have.
Simple font data for LED matrix displays
Use a spreadsheet to design your LED or LCD dot matrix fonts and generate the program code. Continue reading
Using a skillet for soldering?
Experimenting with other ways to solder parts.
After the problem with soldering the gyro, I decided to experiment with using a skillet to solder parts (http://www.sparkfun.com/tutorials/59).
Since I didn’t have a solder paste stencil, I experimented with putting down solder-paste freeform.
The end results aren’t that great. I think a solder stencil or some other method of precise, consistent deposition of solder paste is a must.
Top view:
Top view of solder paste and then soldered part:
North West edge:
South West edge:
South East Edge:
North East edge:
There is decent wetting in the end result but the chip didn’t seem to flatten out and sink. I think the solder profile was not steep enought i.e. I should have heated up the board faster.
I was thinking of using a stencil and manually loading all the parts when I make another board (because of the delamination on the first one), but I think I will make a stencil only for the gyro, attach that and then manually solder the rest of the parts.
Posted in Hardware
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ZVI Soldering parts
After soldering the CPU, I found it didn’t work…
When soldering the CPU to the board, I kept telling myself to pay attention to where pin one was.
When I powered up the board, the CPU wouldn’t respond to JTAG commands!
After debugging for fifteen minutes, I realized I had soldered the chip rotated by 90 deg. counterclockwise!
After the CPU was replaced and verified as working, we attached the gyro but since this is a very thin two layer board, we over heated the board and this caused it to discolor and delaminate. The picture below shows the discoloration around the left side of the gyro.
Below, you can see the delamination as a yellowing discoloration towards the bottom of the image
The above picture shows an issue we have in the US – the difficulty in finding metric screws. Right now, I’m looking for some flat head (JCIS #0, type 1) M1.6 machine screws. The silver colored screws are the M1.6 that are available here. The black screws are JCIS#0, type 1 M2.0 screws that I picked up in Japan.
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