Fixing the case height


#1

I noticed that while the holes in the acrylic cover are correctly sized to lego dimensions, the height of the complete case isn’t.

I built a robot with the brickpi case on its side (seemed like a good idea at the time), and when I came to put a bar across the two halves, it didn’t line up. By my reckoning, the posts need to be reduced by about 3mm to make it all line up in all dimensions.

Has anyone else noticed this and tried to resolve it? If I cut down the posts to the right length, will the screws still go all the way in?


#2

Hey Floppy,

Thanks. This was brought to our attention on twitter as well, so yes, other folks have noticed this!

I’m not sure if you can saw them down; I tried to peer down the hole and see if the threading runs that deep. I could not see it.

We’re contacting our suppliers to see if we can get a version that’s exactly 3 mm shorter; if we can find something, we’ll ship you some for free.

John


#3

Heh, that might have been me on Twitter as well :slight_smile:

I’m not exactly sure it’s 3mm (that’s only guessed by eye), but I imagine you guys are making the right measurement with a proper rig or something.


#4

Hi,
I just received my brick pi and I am very excited! It is really very nice… much more powerful then the NXT etc. But I had some disappointment with the case:

  • as noticed, the height is not standard
  • the brick pi is only held by the GPIOs and is loose: with time it may damage them
  • the height of the plates is not standard (8.0mm), which makes the friction pins a bit loose
  • the size of the lego holes is not very precise (a tiny bit to small, so it is very hard to push the friction pins in, and nearly impossible to push the basic lego brick studs in)
  • what am I supposed to do with the battery?!

For first problem, I measured the height of the box (please confirm it, I just did it with a ruler, a caliper would be better!):

  • a plate is 3.75mm tall
  • the rods are 50.0 mm tall
This is a total of 57.5mm and as lego studs are 8mm, the height should be 8*7=56.0mm. We also need to take into account that friction pins have a little stop in the middle, of height 0.8mm on each half. This stop normally goes into lego holes because they are larger at the ends, which is not the case with this case! Result: (57.5 + 2*0.8) - 56.0 = 3.1mm needs to be cut

The thread in the rod holes went pretty deep so I asked my dad cut the rods :slight_smile: and everything is fine (after some trial/error adjustment).
BrickPi

For the second problem I put three 1x1 plates on the top of sensor 5, motor 1 and motor 4 to stop the brick pi from moving upwards (downwards it is blocked by the double USB and the RJ45 ports of my raspberry pi).
BrickPi


#5

Nice work! I’ve had some success on the other aspects you mention by using sugru. I will blog about these hacks properly at some point, but here are some pics I put on Twitter:

Brickpi corner support made from sugru:

Lego bars fixed to battery pack for proper mounting: https://twitter.com/Floppy/status/403544049019527168


#6

That’s a fantastic hack! Well done sirs!

For the short term, we’re trying to work with our supplier to supply some shorter hex posts. I think this will allow a LEGO-multiple for the case. Great point. For the longer term, we’re trying our hand at 3-d printing a few prototypes right now of a more complete case. Ya’ll will be the first to see about our sucesses and failures!


#7

Sorry for responding a bit late :confused:

Sugru seems great, I didn’t knew it before, but it looks pretty funny!
For the battery pack it is a great idea, but I wouldn’t do it to hold the BrickPi and the RaspberryPi because it is irreversible…

I discovered a new thing that bugs me: the screw that hold the RaspberryPi at the bottom (as well as all the other screws, but it’s less annoying) don’t have flat countersunk heads and prevent us from attaching bricks in some places.

So I am currently thinking about designing and building a better BrickPi case (at least from my point of view, because I don’t see any other people criticizing the original one!). I am not sure what material to use: drilled polycarbonate like the original or 3d-printing (I have to check the prices).

I will start a new topic if this project becomes concrete.