T_Y's Build Log

[AntRoboteer]

That looks really amazing; looking forward to seeing it!

[T_Y]

I've spent some time trying to slim down Percussive Maintenance to get it into the weight allowance. A tail armour panel was added to keep the wires in and the wiring has been tidied up somewhat so it fits inside the shell completely. It's a very tight fit though. I trimmed down some screws and perforated the base in an attempt to shed some weight, but I'm still a little bit over. It then occurred to me to swap out the 260mah battery for a 180mah battery instead which will sort out the weight problem. The 260mah battery is overkill, it only needs to last 3 minutes. The 180mah batteries are also a bit smaller, so it shouldn't be as tight inside. So there's some smaller batteries on the way.

I really like the look of Percussive Maintenance, so I decided to redesign Hello, World! to use a similar shaped shell, but reversed so the long end is the front, and widen the flat section in the middle to give a better flipping surface. The servo that I've got doesn't appear to have a great amount of actuation arc on its arm, so I've also redesigned the flipper system to a) use push rods for pivot points b) use a gear motor connected by interlocked 3D printed arms to get a better range of motion out of the flipper.





Currently printing off a prototype hinge system to see what needs adjusting to make the movement smooth.

I've also been looking for alternate speed controllers - running three quite bulky ESCs in one bot is quite limiting for internal space and weight. The RobotShop website lists some cheap speed controllers, even some dual channel ones. I'm a bit confused by the wiring needed for these ones though. (I believe they're designed for use with things like Raspberry Pis and Arduinos). Take this dual ESC for example. The AOuts and BOuts are for the motors, the VMotor is for input power direct from battery, but what about connections to the receiver?

[peterwaller]

You need to be careful most of those are just motor driver boards that will not work with the signals generated by a standard receiver.

[Shakey]

Those driver boards don't have connections for the receiver. The reason those are 'cheap' is because they are simply a single component of a typical ESC, vitally missing is the micro controller which translated the receivers signals into signals that can be used to control those driver boards.

[T_Y]

Ah okay, that explains the low cost.

[Paulmchurd]

It’s a lot cheaper to build an arduino speed controller. You can see on my build diary how I did it and the price. I’m happy to show you how to do it if you wanted to meet up again? I’ve been using 4 differnt speed controllers. Except the nano 2... as I don’t have a dsmx Tx.

Issue is the sheer farce of soldering and wiring it all together to fine out you soldered something wrong/a solder pad comes off.

[DieGracefullyRobotics]

The Nanotwo does DSM2 and DSMX

[T_Y]

An Arduino controller sounds like an interesting project to do! I'm wondering if it's possible to connect a normal receiver's signal wires to the IO pins on the Arduino instead of using the NRF24LO1, so I can just use the transmitter I've already got instead of custom building one.

[Paulmchurd]

An Arduino controller sounds like an interesting project to do! I'm wondering if it's possible to connect a normal receiver's signal wires to the IO pins on the Arduino instead of using the NRF24LO1, so I can just use the transmitter I've already got instead of custom building one.

Yes you can, it's actually better to do it that way then use the arduino transiever modules.

There is a pretty good video on it via sparkfun. However you need to use the same H-bridge they do. Which uses a lot of I/O. There are better h-bridges.

If your interested in setting one up. I can email you all the code I've used. Or we could arrange a meet up and I can show you/battle test our bots.

[T_Y]

Those Sparkfun videos are quite handy! It looks like that code can be adapted fairly easily to work with other H-bridges, the logic for interpreting the signals should be similar I would guess.

A meetup sounds good, looking at bots that other people have put together would be interesting, plus getting some more driving experience would help!