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
Printable View
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
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.
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.
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?
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
Quote:
Originally Posted by Max
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.
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?
Follow the Woody guidelineon QEV's as main valves. He's one of my teachers, aswel Mike L...
Thanks.
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.
Gears are cut to have the right play when the holes are drilled perfectly concerning the pitch diameter.
But if you want to do the drilling of holes for gears artisan style, a mod 1 pair of gears can benefit from a piece of sigaret paper in between the gears.
Also, to make the calculation for you, I need to know the module.
Or you do as I, and open your smartphone, download the Dennis Martens Gear Spacing Calculator (not in the google play store, it's being spread by Email), and fill in the 3 numbers. Module, Gear 1 and Gear 2
On the relais. A closed relais can take +/-15 amps per 1mm² of contact surface. But it's breaking contact that makes the difference. The lighter the moving contact part is, the faster it can move, breaking the arc fast, but the instant an arc is formed, you're welding or spark eroding the surface.
It's how the 4QD's NCC 70's work with a 40 amp relais. The fet closes the power to the relais. The relais switches, and the mosfet pours in the power again. That means even a cheap relais can switch a far heavier load than what it could do on its own.
I can't find te gear spacing app, is it for android?
The gears are MOD 1.5
Who needs app's when you have calculator :)
Pitch circle diameter = MOD * No of teeth
therefore
Spacing = MOD/2 (N1 + N2) where N1 and N2 are the number of teeth on each gear
(not in the google play store, it's being spread by Email), and fill in the 3 numbers. Module, Gear 1 and Gear 2Quote:
Originally Posted by Max
In short.
33.75 mm centre/centre of the holes.
Could I uses a pair of these 1kg welding co2 bottles instead of a 2kg fire extinguisher in a heavyweight?
http://www.toolsandpowertools.co.uk/...dioxide-1000g/
I would replace the valves with some hydraulic ball valves.
Would a pair of these:
http://www.technobotsonline.com/flan...ails-20mm.html
To connect the wheels of my heavyweight to the 20mm output shaft of the gearbox?
The wheels are 8" diameter.
Also still want to know about if I can use welding bottles instead of a fire extinguisher.
Good news, I finally got my fw flipper working! I had to connect it to a fire extinguisher as my co2 bottle is empty. It worked really well and chucked a brick pretty high even on only 5 bar. Also the hinge or the lid didn't bend this time!
Hopefully I will get it all fully sorted before Guildford as that is the weekend after my GCSEs
Hi,
Does anyone know the rough overall size and weight of the burkert 5404 valves?
Thanks,
Max
No. 2 reasons.Quote:
Originally Posted by Max
Ball valves don't have burst disks.
Main bottles need to be commercialy available.
Thanks Mario, I realised safety posting that the dimensions were probably on the data sheet! But I can't find the weight anywhere, does anyone have a rough idea (like more or less that 1/2 kg)?
Thanks
675 grams according to our kitchen scales.
Does anyone know if the Bosch 750s and Bosch 400s are the same size? Or at least have the same spaced mounting bolts on the front?
The diameter of the can and the spacing of the mounting bolts are the same. Axle is also 12mm, but can have a M12 thread.
Length is unclear , but it won't be longer.
In short, it's a 1 on 1 replacement.
Hi,
I was wondering what people's thoughts were on having drive wheels at the front of a heavyweight? I've heard that at the back causes oversteer particularly as most my weight isn't over the back, in the middle means you can't drive off wedges so that just leaves the front!
The main advantage of front drive wheels is that the weapon doesn't swing out when aiming. Disadvantage, it's a very nervous way of driving (kind of driving a car backwards). Razer solved that by using driven omniwheels on the back, making it a lot more stable.
Sounds interesting, I imagine having a set undriven wheels at the back may help it go in a straight line and restrict over steer, something without too much grip so they can slide.
What do people think this: http://www.esska-tech.co.uk/esska_en...d_air_ms_.html as a pressure relief valve for a heavyweight, I think they were discussed before and found to be a bit low rated but ok?
Does anyone know if it is suitable as a full pressure relief valve, has anyone used it?Quote:
Originally Posted by Max
Thanks,
Max
Seems to be the same as the one we have in Manta so should be fine
That looks exactly what I've got. Roughly the size of a thumb?
Hi,
I was just wondering if anyone used some form of lubrication for their hw gearboxes? I was thinking of perhaps graphite or grease? If I did would I have to seal up the entire gearbox?
Max
Used to grease the gears but the mdf powder from the arena floor would stick to the grease and make lovely grinding paste.....I run them dry now.
Trev
If the gearbox is open, don't use grease.
As Trevor says, grinding paste is grease with abrasive stuff in it.
Right then no grease! I've found that by gripping the axel of my motor ,which pokes out the back of the motor, in a cordless drill chuck and running it works well to 'break in' the gearbox and remove some of the tight points without straining the motor at all!
Good news! I have finally finished my heavyweight gearboxes! They are 10-1 for for use with 8 or 10 inch wheels. They run on Bosch 400s on 12v but I may upgrade to 18v. They use MOD 1.5 gears from technobots, most the gears were 30-40% off!
Here is a picture:
http://i1261.photobucket.com/albums/...18122E13DF.jpg
And a video:
http://youtu.be/YSGHnPsCXjo
Also I have nearly finished my FP pneumatic ram which I made all by myself at school- very chuffed! I just need to drill ports-
http://i1261.photobucket.com/albums/...1858318FDC.jpg
Next job is to make up a manifold to connect everything tomorrow them can pipe up all pneumatics and then make a body for the robot.
Any questions or comments welcome!
Max
How heavy is the piston and rod?
The whole ram ways 3.5kgs, the rod is 20mm stainless rod. It is 63mm bore, 145mm stroke. So it weighs more than it needs to but better to be safe than sorry! The walls are about 6mm aluminium and the end caps are 30mm thick aluminium, its held togther by 8M6 tie rods all 2mm away from the wall of the tube- should do the job.
I don't know the weight of just the rod and plunger but can weight it tomorrow for you, why do you ask?
keeping the moving weight down is a good enginering practice.
Ok I'll weigh it tomorrow, the end cap is pretty thick so should be alright- I'm going to attach some sort of spike to the end as the weapon (not very effective but quite fun) so that could also add some weight. I may add some rubber disks to the inside to act as dampers.
I guess for a spike weapon some inertia is a good thing!
Nice job on the gearboxes. What's the diameter of the output shaft?