New Robots

razerdave · Post by **razerdave** » Sat Jun 05, 2010 8:22 pm

You make 4 motor drive look so easy

I've just today finished Baby Hell's 4WD, its a little overweight (152g) and it needs a bit of tweaking still, but essentially its done.

I have however found problems getting all 4 wheels straight due to the way in which they're mounted, which may have to change at some point or another.

This is also the first time BH has been overweight since I made the original, its always been 147 or less

peterwaller · Post by **peterwaller** » Mon Jun 07, 2010 6:21 pm

I have built the controller and after some initial interference due to insufficent decoupling all is now working. Here is a picture with the receiver removed to show the board layout. I have fitted two dual motor driver chips to cope with the current requirments of 4 HP motors.
http://i109.photobucket.com/albums/n66/ ... MG1040.jpg

razerdave · Post by **razerdave** » Mon Jun 07, 2010 9:22 pm

Is it possible to get 2 dual motor drivers on a board thats no as big as the chassis ?

I only ask because I thought it may be of use to Terrorizer, since its on the limit but could do with more armour, but the Sabretooths a bit on the heavy side

nyditch · Post by **nyditch** » Tue Jun 08, 2010 1:41 am

A buddy of mine has been using these in his ant. They work pretty darn well. The only rub is that you need a separate BEC or receiver power from a weapon controller.

http://www.fingertechrobotics.com/prodd ... ft-tinyESC

alasdair · Post by **alasdair** » Tue Jun 08, 2010 6:25 am

Do you need two motor controllers for a 4 wheeler?

surely you could wire 2 motors into one terminal, and then the steering would be exactly like a 2 wheeler, just with more speed, torque, and general power.

peterwaller · Post by **peterwaller** » Tue Jun 08, 2010 7:47 am

Razerdave it is certainly possible but with 9 variants already available I wasn't looking to go to double figures.
nyditch that is small but you do need one per motor and as you say no regulator. The smallest one I have made so far is just about 1 inch square but that drives two motor has a 1.5A BEC, an output plug for the weapon servo and solders directly to the recever.
http://i109.photobucket.com/albums/n66/ ... MG0939.jpg
Alasdair you need two dual controller chips to provide sufficient current for two HP motors. The drivers I use are tiny and limited to 1.2A so driving 2 HP motors each with a stall current of upto 1.6A is asking a bit much.
correction that should say:
Alasdair you need two dual controller chips to provide sufficient current for four HP motors

peterwaller · Post by **peterwaller** » Tue Jun 08, 2010 4:01 pm

I have just been looking at improving the scoop on Defiant using the new 0.05mm titanium foil. It looks quite good but I am not sure what happens when it gets bent. The following three shots taken with a USB micoscope camera show the old one the new one and the new one with a sheet of paper wedged under it to show the scale and how it reacts to an uneven surface.
http://i109.photobucket.com/albums/n66/ ... ldshim.jpg
http://i109.photobucket.com/albums/n66/ ... ewshim.jpg
http://i109.photobucket.com/albums/n66/ ... ershim.jpg

bitternboy · Post by **bitternboy** » Tue Jun 08, 2010 8:34 pm

I don't think anything could get under that. It looks like great material but could the foil be in anyway damaged by spinners or hard impacts and ruin that edge; compromising the ground clearance?

Andrew_Hibberd · Post by **Andrew_Hibberd** » Wed Jun 09, 2010 2:23 am

That looks very thin pete how flexable is it? let us know how you get on fighting with it.

alasdair · Post by **alasdair** » Wed Jun 09, 2010 7:43 pm

I am building a new robot. I am not going to reveal anything, but i will say that it is going to be called FrANTic. Watch this space!