Ant parts help

Post by **BeligerAnt** » Fri Jan 15, 2010 5:51 pm

The spares you absolutely need are batteries!

Don't forget to charge your transmitter batteries and/or carry a spare set. One set will easily last all day IF they are fully charged.

Spare robot batteries are much more important, especially with LiPo as they cannot be re-charged quickly like NiCd. (Before anyone disputes this, yes, you can "top up" a LiPo for a few minutes, but you can fully charge a flat NiCd in as little as 15 minutes - you cannot do that with a LiPo, it takes at least an hour)

It is also worth investing in a LiPo sack for charging your LiPo batteries, as they can (and do) spontaneously combust during charging. For this reason I would also highly recommend that you design the robot so the batteries are (relatively) easily removed for charging and you do not charge them in-situ.

thebeardedone · Post by **thebeardedone** » Fri Jan 15, 2010 8:02 pm

Thanks for the advice all ...

BeligerAnt, is this the product you are talking about (http://www.liposack.com/products.htm)? That appears to be an absolute must for me to purchase.

Do you leave your batteries in when your robot is not active?

Peter, I will definitely take one off you in the very near future. Next month (or the month after

), I should be in a much better financial position. This month I am going to purchase the Tx ... starting to prepare now.

On a side note, I will try my best to get to the ModelWorld event but I normally work weekends

What is the entry cost to this event?

Regards,
Sam

Simon Windisch · Post by **Simon Windisch** » Fri Jan 15, 2010 9:23 pm

Hi Sam,

It's ?8 plus ?2 p&P

Simon

http://www.ticketmaster.co.uk/event/1F0 ... orcatid=14

Post by **BeligerAnt** » Fri Jan 15, 2010 9:27 pm

Yes, that's the thing. They are available under different trade names from several suppliers. Robotbirds do one for about ?10. Most model shops probably sell them these days.

Whether you leave the batteries in when the robot is inactive depends on how paranoid you are I guess. But let's face it, your MP3 player, camera and laptop almost certainly live happily with Lithium batteries in...

Modelworld runs from Friday to Sunday, entry cost is not on the website yet, but from memory it's around ?6 - ?8.

thebeardedone · Post by **thebeardedone** » Fri Jan 15, 2010 9:40 pm

Thanks for the link, Simon.

I should be able to make the Sunday, if I can get the day off work, so I will come and find you there. It will be good to see my competitors in the flesh

Beliger, I contacted one company that was listed on the website as a dealer but they don't stock them anymore, but a quick search on eBay revealed a whole bunch under different brand names, so I will probably pick one up from there.

Regards,
Sam

thebeardedone · Post by **thebeardedone** » Wed Jan 20, 2010 9:44 pm

Andrew_Hibberd wrote:Rrecently i have been making my own control boards using the baby-oranguatan AVR boards

http://www.pololu.com/catalog/product/1220

Petes boards offer a nice small unit which also reduces the ammount of soldering required. I use two of these in strafen so 3 channel mixing to control 4 motors. It all depends on how much you need the robot to do.

I am taking the unit of PeteW, but these could be extremely useful for future projects. I will pick one up to test out on Bell (my second ant).

Regards,
Sam

thebeardedone · Post by **thebeardedone** » Mon Feb 01, 2010 7:02 pm

Ok, after some careful thought and some freehand designs, I have decided to put 'Chuck' on the backburner and start with another antweight. The reason I have decided on this is that there is a lot of flipper ants out and about on the scene and I want to do something "different" (it's not that different but based on my research there is fewer numbers of the pusher ant). I also feel that by concentrating first on getting a good well built ant under my belt and gaining some experience I can then develop and creates ants that are better designed and have an effective weapon. This will be achieved by speaking to you guys at events and on this forum to fully understand what building a combat robot is about.

So, after my rather self-indulgent explanation, I would like to propose to you my new (again) parts list:
Planet 5 Tx
PeteW Planet 5 Rx/Ctrl module
4x 50:1 Pololu HP GMs
F3P 350mA 7.4v LiPo battery
6v regulator module
2mm polycarbonate body
Either DB foam wheels or my own urethane tyres that I am experimenting with.
Fixings and securings

I understand, Pete, that after the PMs with you, the module you designed can handle four motors ok.

Team Orr, I did the experiments with polycarbonate and I agree with you that 2mm is ample for this class of robots.

Regards,
Sam

peterwaller · Post by **peterwaller** » Mon Feb 01, 2010 7:18 pm

As I mentioned the stall current on the HP's is 1.6Amps each so in theory too much for the controller but it is almost impossible to stall the wheels on an ant unless somthing jams them. I did a test using 4 50:1 HP in Dominant and although I never used it in actual battle it work well. The controllers have thermal shutdown so even if you do exceed the current there should be no damage.
You don't need a 6 V regulator module as the receiver is powered from the 5V regulator on the controller board and the drive motors run at the full battery voltage.

olivers · Post by **olivers** » Mon Feb 01, 2010 8:59 pm

I don't wan't to steal business away from anyone but I have a cheaper suggestion for speed controllers.

I use standard servo controller boards to power the geared motors. Just unsolder the standard motor and solder wires and the new motor on. Central the feedback potentiometer and it's a quick ?5 speed controller.

Saynig ?5, I have just brought 6 Futaba servos off ebay for ?20 so ?3.30 each, so ?6.60 for 2 speed controllers for 1 ant.

thebeardedone · Post by **thebeardedone** » Mon Feb 01, 2010 10:14 pm

peterwaller wrote: You don't need a 6 V regulator module as the receiver is powered from the 5V regulator on the controller board and the drive motors run at the full battery voltage.

Ah, that was going to be my next question.

@olivers: I have heard of SC being done like this in the past. In my other robots (not sumo or ants) I have used UJT/SCR Ctrl Circuits, MOSFET Ctrl circuits and even 555 ICs as Ctrl circuits.

Regards,
Sam