Peter Wallers Robot Ramblings

[Kyro]

simple answer... fill the pits with water... that'll stop fighting in the pits

[peterwaller]

Working on a new version of my spring / elastic flipper design.
https://youtu.be/vgXgFGJsj54

[peterwaller]

Here is the finished robot.

[Kyro]

looks good. i cant wait to fight this at our next meet...

i really like this concept.

is the flipper slower now with the springs as opposed to the bands? i would figure its slower but a bit more power...

i learned a lot about kinetic energy regarding bands and springs from my years of building slingshots and slingbows... generally many smaller bands will be faster than one larger one... this is also true of springs so having 2 instead of one is a step in the right direction

[peterwaller]

To be honest I am not sure my physics is a bit dodgy in this area.
I thought it was about as quick but that may be due to the springs being stronger than the bands I was using.

[peterwaller]

One of the biggest problems I find as I get older is starting more and more projects without necessarily finishing any.
Someone on here mentioned the RZ7899 motor driver that looks really good.
It is similar in spec to the DRV8872 I use in my latest design but doesn't have the pad under the IC that has proved difficult to solder by hand with an iron.
Added to that the fact that the small orange receiver is now obsolete (even though I have a good supply of them) I decided to do a new board using the RZ7899 and the lemon receiver.
I ordered some boards yesterday from PCBWay and will let you know how they work out assuming I do finish this project.

[MarkR]

I'm using the rz7899 in the Malenki ESC. It's a single channel H-bridge in a soic8, I don't find them to be difficult to solder unless the board has too much copper around (particularly the 2 ounce copper).

The nice thing about it is that it has a good wide voltage range, quite big claims of max current, and doesn't need an auxilliary power supply; there is literally only one supply pin, which drives the chip's guts as well as the motors.

I also haven't managed to break one yet

[peterwaller]

The PCB's have arrived that's just 5 days from uploading the file.
Here it is next to the lemon receiver.

[MarkR]

Looks good, nice big rings around those through-hole pins, much bigger than the ones on the RX.

What design software did you use?

I am assuming it's a single-sided layout, IC3 and IC4 are the rz7899 ? I see the pads connect 5-6 and 7-8

Mark

[peterwaller]

It is a 2 layer circuit board with components just on one side.
I have a very old copy of Protel Client98 (1998 vintage) that I have to run on an old Vista machine because it won't run on Windows 10.
I am just trying a later version of Protel DXP which does seem to run on W10 so I will probably migrate to that.
One problem they both split the drilling data on the gerbers into two files that the PCB manufacturers can't use but PCBWay can just use the protel PCB file direct so it is not a problem.