Posts by Upstart

    Maybe for beginners, tests and special robots we should set aside some more time for fun-fights and demos.


    For the Raptor competition it seems most of us agree with a 1KJ limit and no restrictions on parts.

    Right now that would be the same rules as for Feathers.

    The only difference might be, that with Feathers the arena determines the limit and with Raptors the result of the previous event.


    Again... this is just an idea and interpretation of what I read here.

    I know for a fact that:
    For new participants damage is very important. they are often Young participants who have just enough money to build a robot. Money for spare parts is often not there, nor is knowledge of how to prevent serious damage. There is a lot of interest in the hobby, but when they see the professionals, many drop out.


    This is my personal opinion don't get angry:

    To keep enough robots in a class I personally would have no problem trading the Raptor class for a Featherweight Sportsman class. You could then still use your raptor as a cluster for Full combat or the Sportsman class. So all current robots are still usable then.
    I still think that a Sportsman class could mean a lot to the sport.

    My opinion on a few things :smiling_face:


    Eggbeater vs Drum:

    A featherweight Eggbeater is way more expensive and complicated than most people think.

    You can't put the bearings in the weapon so you need to build bearing blocks.

    These need to be aligned else the weapon generates too much fiction.

    If you have a mill no problem.


    Then you need to build the Eggbeater. The best material for this kind of weapon is Hardox.

    The Hardox must be thicker then the shafts you want to use, mine is 25 mm with 20 mm shafts.

    You need to get the material cut by waterjet with a minimal taper.

    The waterjet company has to cut the material slower and this will make it more expensive.

    If you have a big taper the weapon will not balance well and shake your robot to bits :grinning_squinting_face:

    Then you have to turn the shafts from square to round shafts.

    You need a big late to make the interrupted cut on Hardox and a even bigger late to cut the radius from the shaft to the Eggbeater.

    Aligning is a pain and it you can't do the job yourself you have to pay a lot for this part.

    The pulley needs to be connected to the Eggbeater and should not weaken the shaft, this is already the weakest spot in the Eggbeater.

    All these things make it expensive and harder to build... so be aware.


    Easiest way to build a weapon (in my opinion)

    Use a dead shaft and build a drum with disks on both sides.

    The dead shaft makes the alignment easier and you dont need a mill to make the holes to mount the dead shaft.

    On a small lathe you can make the bearing pockets in the aluminum drum. If you dont own a lathe then many people will do this for you at minimal cost.

    The holes to mount the disks can be made on a pilar-dill. Just create a template on a 3D printer.

    Get some disks, again Hardox is your friend :face_with_tongue:

    Make the mounting holes in the disk part of the big hole in the center, this is cheaper to cut!

    The inner hole should be cut with minimal taper, the outside can be cut faster, again cheaper to cut!

    Get some shoulder bolts to mount the disks. Make a groove in the drum and your pulley problem is also solved.

    Don't make this type of drum to wide this won't work well.


    It all depends on what you can build yourself.

    Outsourcing complicated parts/jobs is expensive.


    For speed and wheel size:

    I like 80 mm wheels and 700rpm (minimum) to 1000rpm on the outgoing shaft for both Raptor and Featherweight.

    Wow. It's a treasure-box for developing. First, I have to read and understand all the know-how about the different protocolls. As the Transceiver is not for me alone, I will use a "normal" PPM-control to the transmitter-unit.
    But first to understand all....

    Yes I like that project a lot!
    PPM is supported using a protocol selector switch.
    If you want transmitter menu integration then you need to use serial communication.


    If you like this project also take a look at the deviation project https://github.com/DeviationTX/deviation
    Used their transmitter protocol code to reverse engineer the Bayang receiver code and build a custom receiver based on the NRF24L01.

    Thank you for the tipp!
    Normally I had used the DIY-Modul from Orange. The receiver is one of the cheap orange, compatible with Spektrum.
    But this betafpv seems to be a better way.

    The one I put in the link is a simple/cheap one that works with some protocols including Bayang (only NRF24L01 chip).
    In my own transmitter (Taranis & modified Turnigy 9X) I have the "iRangeX IRX4 Plus 2.4G CC2500 NRF24L01 A7105 CYRF6936 4 IN 1 Multiprotocol" this module support supports almost any protocol. And with serial support in your transmitter you can select the protocols form the transmitter menu.
    For more information on the TX module see here: https://github.com/pascallanger/DIY-Multiprotocol-TX-Module
    You can build your own or buy a complete module it's all opensource.

    Good to hear about that. I am just using some CPU modules that we are already using at work
    for different tasks (mainly wireless routers and building automation controllers) and for whch i have
    full acess to the linux/kernel working on them (and to the developers, if i need something very exotic...)

    No problem... just wanted to let you know... enjoy the build and hope to see your project at the next event.

    A few years ago I made a receiver from a esp8266 board using a custom UDP based protocol, in the process of buidling the wifi receiver I discovered the Bayang protocol that is used in cheap chinese drones.


    The latency is much lower and the parts way cheaper.
    There are TX modules available for module-based-transmitters like this: https://betafpv.com/collection…temodule-bayang-rf-module
    Or search for multiprotocolmodule or deviation transmitter... Yes you can build your own if you want.


    We used the system for kids to have fun at tech educational days. See: http://www.dutchrobotgames.nl/forum/viewtopic.php?f=8&t=1952
    The small transmitters used at the tech educational days where included with 10,- drones, and survived 3 of these events (dropped multiple times) and still work :smiling_face:
    The system even supports telemetry and has never failed me.


    Used the system in my (competition) antweight and trust it enough to put it in my beetleweight.

    Thanks! In the video the weapon runs around 5000 rpm.
    In the final situation it should run around 8000 rpm.
    The egg beater is only 1.6 kg Hardox 450 so its not a monster, but I think good fun for an event like INDI Robot Games.
    At the moment I have a design for a 3kg drum for other competitions.
    Maybe later this year I will try to build this drum... after I finish building my first beetleweight :smiling_face:

    Testing the Racerstar 80A weapon ESC with BLHeli_S firmware and a new HTD5 belt.
    The weapon sounds much better now.

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    Thanks! I was surprised too :smiling_face:
    Really like how it handles.
    In the future I can place the wheels 10 mm more to the front of the robot this should make it even better.

    @dkf Thank you!
    I will upload some pictures later.
    Here is a video of the first weapon test.

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    So far I made 16 wheels and had only 1 failure (also like jelly) I made a too small batch of polyurethane.
    The minimum of each component I use (now) is 80 grams.
    Also be aware that the product has a short shelf life.