Team MedBots

[maddox10]

Re: Team MedBots

Or parallel wind the turns, less resistance, more amp draw, more torque at the same voltage.

[Max]

Re: Team MedBots

Oh I get it- I didn't realise you meant put in extra coils , I thought you meant put in a huge chunk of copper between the commutator and the windings for some magnetic induction reason!

[typhoon_driver]

Re: Team MedBots

I was going on marios thinking

[Max]

Re: Team MedBots

Hi,
I am making progress with my idea of making my own speed controller.
I decided I would try to make a miniature speed controller with my arduino and the electronics I had lieu my around-



I used an H-bridge microchip an then just lots of wires!
It controlled the speed of one small motor and a servo and has the ability to run one more motor.
My plan is to use one of the microchips from an arduino then make my own circuit board to wire it all up, then I will use a lot of mosfets or some solid state relays. I want it keep it as simple as possible to make it reliable and rugged.

[PJ-27]

Re: Team MedBots

Cool! Are you using the Arduino to just convert the output from the Rx to PWM for the chip? Just wondering if there are smaller cheaper options.

[Max]

Re: Team MedBots

Yes that is pretty much all the arduino is doing. I imagine it could be done with a smaller cheaper chip but it seems easier just doing it with an arduino- I understand it and can program the chip on my arduino and the actual chip only costs £2

[Merkabah_PT]

Re: Team MedBots

I saw a guy in some website using a regular servo pcb, with 2 schmitt triggers to control 4 heavyduty MOSFETS. I will try to find a link and post it.

[Merkabah_PT]

Re: Team MedBots

I found the links.

First one is a guy using the servo pcb outputs directly to the mosfets with some problems, then a guy in the coments explain him that he should use schmitt triggers.
http://letsmakerobots.com/node/20466

The second one is from the guy in the coments explaining and testing is solution. He drives a 5A motor, but it's just a matter of using bigger MOSFETS.
http://letsmakerobots.com/node/34692

It's a very simple and small DIY ESC, and you can even and an internal UBEC.

Hope this helps. I will for sure try it out when i build a more serious robot.

[Max]

Re: Team MedBots

If I use a 2kg co2 bottle as a main tank and a 60mm bore, 300mm stroke ram am I right in thinking I will get about 20 actions?

[Max]

Re: Team MedBots

Also, could I use a QEV like this:
http://sigma-valves.com/pdfs/Quick-Exha ... v-0110.pdf
Or like this:
http://www.parker.com/portal/site/PARKE ... tky=VALVES
To control a high pressure ram along with a high pressure 5/2 valve (hydraulic?)
Thanks,
Max

[maddox10]

Re: Team MedBots

If I use a 2kg co2 bottle as a main tank and a 60mm bore, 300mm stroke ram am I right in thinking I will get about 20 actions?

Depends on used pressure.

If it's 8 bar, you can get 100+ single actions out of it.

If you go FP without any liquid stopper you will be glad that it's 20 actions.

Also, 60mm bore is a strange size. Commercialy 63mm bore is more common.

[PJ-27]

Re: Team MedBots

Sorry for the slight hi-jack, but when using a QEV as your main firing valve how do you control it remotely?
I thought they all had manual pulls? Or do people just modify them so that a servo/solenoid does the pulling?

Also can you get QEVs that allow flow to go straight through? Looking at that design it has to go through a bend, which on an exhaust valve that's meant to be quick, seems a slight flaw?

[maddox10]

Re: Team MedBots

Follow the Woody guidelineon QEV's as main valves. He's one of my teachers, aswel Mike L...

[PJ-27]

Re: Team MedBots

Thanks.

[Max]

Re: Team MedBots

How much space should I allow between two mod 1.5 gears?
Ie. if I want to mesh a 15T with a 30T gear what distance would I put between the holes for the centres?
On a different note, could a relay rated at for instance 30A switching current actually take 150A once it's closed or can it only ever take 30A?
Thanks.