I was thinking of ways to power the Mini Atom Bot Board (and SSC-32) while developement because it seems people only get 1-3 hours out of these battaries and its annoying to have to stop work because a battery died and you dont have any more charged. So, I came up with these idea:
Power via the DB9F? I am sure you can connect the gnd pin and vcc pin from the DB9F to the VCC/GND on the VS/VL blocks. One problem, I looked at the Mini-ABB schematic and I didnt see a VCC/GND on the DB9F. Is this because it doesn’t exist? Or because it was not planned on being used?
Well, heres my second method of powering it. USB! The usb has 5v line and GND. You could connect those to the VCC/GND on the bot board. Then just tie the USB and DB9F cable together and pretend its one thick ass cable. I know the ABB can accept 5v but would most servos function well at 5v? A lot of the time I see 6v and 7.4v used, never seen 5v used on a robot. Is it because 5v batteries dont exist? Because I never seen one.
Think either one of these is possible? And if the DB9F doesn’t have power running through it, il make it have one
-robodude666
P.S. Sorry if these were posted before. I searched for 10min and found nada!
It would probably be good to start a thread in the new electronics discussion group on making bench power supplys for development work. A bench power supply would eliminate battery issues during development. It would save a lot of $$$ for those that are working with non rechargable batterys.
well technically you are not supposed to pull more than 0.5A (500mA) from a USB port. If you have a self powered hub, and it isn’t smart enough to monitor load current on each hub port, you may get it to deliver 2A. The contacts on a USB connector are probably good for 1-3A depending on the connector. Most servos will run down to mid 4V range well enough but you also have to remember the power (torque/speed) of the servos is going to drop with supply voltage.
Why not just buy 2 or 3 battery packs and a quick charger, like for RC cars? It may be cheaper than a bench supply capable of running a full biped without servo stalls.
Why not? There are many things you can buy that are powered by USB. I seen a USB cup warmer, USB clock, USB fish tank (fake fish), USB you-name-it! They are all powered by USB.
well if your gona just run programs on the atom bot board, I guess there is no harm. If you plan to run 20 servos from this source, the servos will cause a nice load and who knows what might happen.
And they all draw under 500ma (0.5A) OR have their own external power supply.
So if you power the servos from somewhere else you can probably power the micro part from the 5V, but do not try to power the servos from the USB or you risk smelling the special smoke.
Well, there’s always the DIY approach to making a power supply.
Going from memory, what’s needed is a transformer (two inductors, a.k.a. “coils”, wrapped around an iron ring) to step down the voltage.
Then a fullbridge rectifier (that’s just four diodes aranged nicely) to modify the AC sin wave into a positive “bouncing” current.
And then a bunch of filter caps (and an inductor?) to smooth out the “bounce” into a proper DC current.
Anyone done this before?
I think I found this in a Digital Electronics book that I got from the library.
When I go back, next, I’ll see if I can get it again, so I can post a schematic.
Now you’re talking about commercial devices! Before you were talking about soldering wires onto a DB9, which is directly powering something from the PC’s internal power supply! The USB port may be fused, or some other protection may be in place.
Actually Jim, I was talking about both. DB9 and USB. I mentioned that USB has a 5v power thingy in one of its pins and thought that might be useable for a powersupply while your developing with the ABB or SSC-32… I also asked if it would be possible to somehow get 6v to the DB9 from the computer’s internal power supply.
The USB port can probably power the boards, but not any attached motors. Most computer power supplys supply +5v and +12v. The +12v supply is usually weak compared to the +5v part. You can use a +5v regulator and a diode or LED on the regulator ground to get colse to +6v when connected to the +12 supply. I wouldn’t try powering any motors from the computer power supply. External power supplys are fairly inexpensive.
I can’t help anyone out with specific part numbers, since I haven’t built this circuit myself, nor plan to.
I don’t like playing with household AC, when I can help it.
Looking at this, though, I’m wondering if you’d even save money buying the parts and making it yourself, since a regulated 5V wallwart is only about 15 bucks.
::points down at red disclaimer::
I will not be held liable, nor pay your medical bills, or even rush over to the hospital to pat your hand and mutter simpathies when you electricute your self.
Be warned.
