New Robots

[Team Orr]

new bot!!!

Dead Meat
( some of u guys may have seen it at aws26)

Weapon: pusher
Armor: polycarb
weight; 125 g's
drive: ? but it uses motors

[Antweightsforever]

Hi,
We are all built and nearly ready for the Reading Robot event. One problem however is that at times we get interference which makes the motors jitter a fair bit. It depends on how close we are with the transmitter but it?s uncontrollable for a time which is not great !
It?s only since I have tried to keep the aerial wire inside the bot, I?ve used a small piece of card and wound the full length wire along the card. The motors do not have any suppression that I can see, would it help if we put a capacity across the motor terminals ? if so what size ?
Or do I need to cut the aerial down a bit or position it more carefully ?
We are running an old 27Mhz RC system with a sabertooth5, 2 x Lipos and 4 x precision microdrive motors.

Thanks
Chris

[EpicentrE]

I would suggest trying to have your aerial somewhere near the outer skin of the robot (either inside or preferably outside if you can get it somewhere where it's not too vulnerable, especially if any of the robots armour is metal), and as far away from the motors as possible.

Putting capacitors across the motor does reduce noise, but I don't know enough about it to tell you what size you need, so I'll let someone else do that.

Whatever you do, don't cut the aerial down, that will make reception far worse. Try to position it more carefully as I've explained above and always ensure your transmitter aerial is fully extended, as that makes a huge difference.

[BeligerAnt]

As Scott says, keep the aerial well away from the motors.

It's also worth keeping the receiver away from the motors, and both the aerial and receiver away from the speed controllers.

You also need to keep the aerial away from the receiver.

Of course, there's a limit to how big all these distances can be within a 4" cube!

Suppression capacitors on the motors will also help, but they do need to be right next to the motors to be of any use. If you're tempted to put them on the speed controller PCB, don't bother as they won't do much.

You can use one capacitor across the + and - terminals of each motor. You can also try capacitors from + to case and - to case.
You can also connect the motor cases to the negative side of the battery ( your "system 0V" )

You need some small ceramic capacitors, around 100nF ( 0.1uF) is a good value to try. Suitable parts are available from Maplin, Rapid Components, Farnell, RS etc

If you have intermittent reception problems, also check that the aerial wire is still connected to the receiver! No, it's not a joke we have had this problem. The aerial wire is made of very fine strands, and it tends to fracture where it is soldered to the PCB. The plastic insulation doesn't always break and sometimes it works, sometimes it doesn't.

[Simon Windisch]

Also, keep the wires between the motor controllers and the motors as short as possible. You could also try reducing interference by putting a layer of foil (covered by selotape) between the workings of the robot and the receiver and aerial.

Simon

[Antweightsforever]

Excellent, thank you guys. See you on Sat.

[Cavecrusher]

insert = "tiny voice inside your head"

hmm, spektrum 2,4 ghz might be the answer

end = "tiny voice inside your head"

[Team Orr]

hi

ValliANT has been completely re-built out of 4mm + 2mm polycarb

NO MORE GAFFA-TAPE!!! only glue and bolts... ok, theres a tiny bit of gaffa to stop the armor from wobberling...but the armor has been cut with a bandsaw (i could swear i sheared the bolts of 100 pairs of scissers when i cut the origional armor) so its dead straight

it looks SSSOOOO much better

dead meat is coming along o.k

watch this space

jack

[Remote-Controlled Dave]

New bot.

Name: Egg
Type: Walker
Drive: SD200's
Weight: 182g
Armour: sacrificial plastic
Weapon: 30g saw blade

[Andrew_Hibberd]

With a name like egg we need pictures