Team 1202 Build Diary

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Spaceman
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Team 1202 Build Diary

Post by Spaceman » Tue Jun 03, 2014 8:11 pm

Entry 1: Hello!

Hello there. after all your great help I have kicked off my robot building. As I like the build diary's I have read here I want to keep one myself, If only for some feedback and advice.

So after a few hours building I have this:

Image

The Item to the left is my 4" calibration cube as I'm sure you guessed. the item to the left is my first bot. its a "box on wheels" made of 3mm PVC foam that sign writers use

Image

While I admit its not the most competitive of shapes, it should, when functioning, at least work.

Image

One possible problem may be the weight distribution, which at the moment puts most of the heavy bits over the (as yet uninstalled) slider. I have also not wired up the beast as yet. I need to fabricate a power lead to power both the speed controller and receiver.

A question. do I need a failsafe and a power switch/ link to the bot?

right now it weights in at 125grams in this configuration.

So there it is.
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Remote-Controlled Dave
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Re: Team 1202 Build Diary

Post by Remote-Controlled Dave » Tue Jun 03, 2014 8:27 pm

This is ace, my kind of robot!
You need a way of plugging the robot in, yes, but this doesn't have to be a switch or link and as you have no dangerous weapon, you just need to make it accessible. Could be as simple as unplugging the battery from the receiver.
As far as 'uncompetitive' goes, you have a fairly similar set up to the robot Hogi, which always does really well at recent events. If you get a wedge on it and play with the distribution you can definitely win a few fights!
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Re: Team 1202 Build Diary

Post by razerdave » Tue Jun 03, 2014 9:00 pm

You say you need a power lead to power your speedo and RX. Just to clarify, you put power to the speedo, and it will provide 5v to the reciever it's plugged into. no need for s seperate power line for it unless you're powering something like a servo from it.

Failsafe: not essential if its not a spinner, but you do need a way of turning it off; a switch, an accessible power plug, whatever.

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Re: Team 1202 Build Diary

Post by Rapidrory » Tue Jun 03, 2014 9:28 pm

Looking very tidy!

Be interesting to see how the PVC foam stands up against spinners, but then even if it doesn't, there's something oddly satisfying about getting smashed ( though other may not agree with me there :roll: ) But yeah, you might want to 'spend' some of your last 25g on an aluminum scoop or something to help keep the spinners out.

As Dave says, most speed controllers (if not all?) supply power to the receiver through the servo connector leads, so you don't have to worry about extra power leads; just need a battery connector on the sabertooth and you'll be good to go. If I remember correctly, the aux power on the sabertooth is only rated to 1A, which is fine for a receiver and a small servo, but if you wanted to run a bigger servo off it at some point then you might have to set up a separate heavier duty voltage regulator to supply the power needed. The voltage reg is needed as most servos run at a maximum of 6V and so can't run straight of a 2 cell Lipo.
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Re: Team 1202 Build Diary

Post by Remote-Controlled Dave » Tue Jun 03, 2014 10:38 pm

Yes, what Rory says is true, running a receiver and weapon servo using the power supplied through a sabretooth doesn't work too well without separate regulators and things, but not something to worry about just yet.
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Re: Team 1202 Build Diary

Post by Spaceman » Wed Jun 04, 2014 7:13 am

So just to clarify in my head: the servo signal connectors on the speed controler also function as power connectors? Or dose a seperate power connector need to be soldered to the speed controller pcb?
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Re: Team 1202 Build Diary

Post by peterwaller » Wed Jun 04, 2014 7:44 am

You require a red JST connector to join the battery to the speed controller something like this:
http://www.ebay.co.uk/itm/8049-RC-JST-L ... 53f18d8ac0
The speed controller provides the 5v power to the receiver via the two three way flying leads that connect them.
Just make sure when you connect the battery to the controller you get the polarity correct or you will blow it.
If at a later date you want to add a servo you will probably find that the controller 5v regulator will not provide enough power for the servo so you will need to add an external regulator.
Good luck and look forward to seeing it in action.

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Re: Team 1202 Build Diary

Post by Hogi » Wed Jun 04, 2014 3:57 pm

your robot is very similar to my hogi. great minds! deffinitely worth putting a wedge on the front. most pushers around nowadays are 4 wheel drive but hogi is only two wheel drive and he does perform quite well against other pushers. ground clearence is the key and for that my advice is to put a strip of acetate along the front of the wedge. it doesn't always work but it deffinitely makes the job easier.
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Re: Team 1202 Build Diary

Post by Spaceman » Thu Jun 05, 2014 6:57 am

Quick tech question. Is there a datasheet of the lemon rx?

looking at the rx I assume the ground to be the pins closest to the PCB edge with the +5V being centre and signal the innermost.

Again my assumption is the cables on the sabertooth are Brown for ground and yellow for signal. ive only really used Futaba stuff before and the colours there are different.

Not quite ready to wire the beast up but best to clarify before I do.
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Re: Team 1202 Build Diary

Post by Rapidrory » Thu Jun 05, 2014 8:17 am

Haven't seen a data sheet for the lemonRX, but it's written on the PCB silk screen on the back; Ground is the closest to the PCB edge, +5V is in the middle, and signal is on the inside row. The signal wires from the sabertooth are brown for ground, red for +5v, yellow for signal, so your assumptions are correct. Though the system is designed that if you plug in a socket back to front accidently it doesn't blow up the receiver, which has saved me more than a few troubles!

The lemon's bind slot is the one on the far left hand side; you'll need to use the bind plug that comes with it to link it to your transmitter first time you power it on. It'll stay linked even when the power's off, so you should only need to do it once..
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Re: Team 1202 Build Diary

Post by Spaceman » Mon Jun 09, 2014 6:03 pm

Hello

Quick update. Ive soldered the motor wires but hit a battery snag. The control wire for the battery pack is too small to plug into my charger. Is there a adaptor or do i need a diffrent battery or charger?
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Re: Team 1202 Build Diary

Post by BeligerAnt » Tue Jun 10, 2014 8:47 pm

From the pictures in the first post your battery looks pretty standard. The white 3-pin connector is for "balance" charging the battery which is better for it but not essential for these small 2-cell batteries. It gets more important for higher capacity packs of 3 or 4 cells (or more!).

What charger do you have, and what connector(s) does it come with? Most of the chargers that I have come across come with a set of cables to connect to all the common R/C battery packs and the red 2-pin JST connector on your battery is probably the most common for this size of battery pack.
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Re: Team 1202 Build Diary

Post by Remote-Controlled Dave » Tue Jun 10, 2014 8:53 pm

You can also shove a male JST like that into a femail Hitec plug as long as you get to polarity right. Probs not recommended but works for me!
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Re: Team 1202 Build Diary

Post by Spaceman » Tue Jun 10, 2014 9:15 pm

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Re: Team 1202 Build Diary

Post by Remote-Controlled Dave » Wed Jun 11, 2014 6:08 am

That one seems to come with the correct lead...the little red one on the far right of the picture. Though it does only go in one way round.
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