The thing is, Fritzing has a schematic editor and display; I don't know why users don't jump to the "next level" and post those...

...but I'm not at all sure it will work with ABS...

I am certain.  Normal epoxy does not bond to ABS.

Well - when I think of epoxy - I think JB Weld. That said, I have the cover of an old battery from a Motorola "brick" phone that I use occasionally for mixing epoxy; I can bend it and pop the epoxy off (mostly). Not sure if it was made of ABS or not...?

With an interesting exception: openings in the ABS give the epoxy a "bonding" point.  I have had success "gluing" tactile pushbuttons into openings.  The epoxy forms around the opening edges holding the pushbutton in place.

One thing I had done to get some of the epoxy off that battery cover was to use a hammer and chisel it off; but I found the epoxy would stick better the next time around (perhaps the gouges were making it easier to "stick"). So you could probably just sandpaper it some to make it stick. Worth trying out, at least.

I've found JB Weld to be good for sticking together just about anything; my "worst" application was on an anti-backfire valve on my 79 Bronco. That valve is virtually impossible to find, and the one that I did find (off a junker engine) was broken. I JB Weld'ed that thing up, and it's been on that exhaust header for several years now, without failing.

I've also seen JB Weld hold together a blower on a diesel engine, on my brother-in-law's old Ford dump truck; the blower cover was an aluminium casting, and had cracked. My brother-in-law had no way to weld the aluminium, so he JB Weld'ed the crack. It held for over a decade, then the blower failed again. That's when I first saw it. It had cracked in a -different- spot; he told me about using JB Weld on it the first time, and showed me the repair he had made before; it was still holding fine. Of course, after the second crack occurred, he decided to get a replacement blower.

All anecdotes, of course - and says nothing about ABS.

Gorilla Glue (or another polyurethane-based glue) might be another possibility. Something else to try might be to get some ABS solvent (ABS pipe "glue") and take a little bit of it and mix in some ABS shavings to make a "plastic blob", then embed the standoff into the blob onto the ABS piece you are working with (probably a metal hex standoff would work best - basically, the idea would be the inside threaded end of the standoff would secure it longitudinally, while the hex part being embedded would keep it from rotating - but that's all just a guess).

I am wondering if anybody has a good suggestion for a particularly quiet(and preferably fast) servo motor? I have bought a few, and they all seem relatively loud, but I feel like surely there must be some made for certain applications which require a quieter device....?

There are two main factors that will determine how quiet a servo will be:

1) How it is constructed.
2) How much you paid for it.

Most cheap servos are constructed with plastic spur gears and plastic bearings. They won't have tight tolerances. More expensive servos will use a metal output gear, a bronze bushing on the output shaft, and tighter tolerances. They still can be pretty loud. Spend a bit more (or a lot more), and you can get metal gears and ball bearings throughout.

Finally - if you really want less noise - look for a servo that uses helical cut gears; I am not even sure they make such a servo, honestly, but if they do, it will likely be the most quiet servo you can find (provided you are willing to spend the money). You can find quiet DC motors that use spur gears (such as Pittman gear motors) - but then again, they aren't cheap either, so if you are looking for a similar quality servo, expect to shell out the cash.

Rather than drilling holes, another solution you can try is:

1) Attach the standoffs to the board you want to mount.

2) Apply epoxy, super-glue, or some other similar multi-purpose/multi-material high-strength adhesive to the ends of the standoffs.

3) Position and apply the standoffs onto the surface your want to attach to.

Once the glue sets, you can then unscrew the board from the standoffs, and they will remain in place. Be careful not to get any glue onto the board or the screws holding it to the standoffs, of course.

Adafruit sells this inexpensive peristaltic pump:

http://www.adafruit.com/products/1150

Note, however, that the tubing in it is -not- food grade, but it should be possible to purchase such tubing and replace it.

Something I'm curious about: Will we ever see any of your code, schematics, or physical setup, sirch?

Go back to basics:

Plug in the Arduino via USB only. Is it on?

If so, upload the blink sketch. Were you successful? Is the LED blinking?

Ok - if so - unplug it from the USB and plug it into the power supply (honestly, 12V is a little high - but it will work, plus the Arduino has reverse polarity protection).

Does the LED blink? If so - then we can move on.

If not - well - something isn't right with your Arduino.

It may have a heatsink on the bottom, but the devices are on the top and FR4 PCB material is not a good conductor of heat.
I presume there are lots of vias under them but not 30W's worth!

If it were an aluminium PCB that might be difference, but its clearly FR4 from the edge in the photo, and has through-hole
components to prove it.

I'd want to pull the heatsink off; if it were done right, the heatsink would have "bumps" to mate with the backside of the BTS7960, and the PCB would have hole for the bumps to fit through; that and some heatsink paste should work well. That said, I wonder if the heatsink itself is large enough?

I'd personally go with a serial servo driver board, like those offered by Pololu (http://www.pololu.com/catalog/category/12). With them, you can potentially control over 100 servos, each addressable. The boards can be daisy-chained to allow you to control multiple servos, and you only need a few pins for control. The only downside is that there isn't (?) a simple library for using them, but Pololu does provide interface code that is fairly easy to understand.

I'm really wondering how you have these shields hooked up; do you have two of the Pololu shields stacked on top of each other, so that you are controlling them in parallel? Or have you somehow rewired the pins?

Of course, you only state the pins for the one Pololu shield - not both; if you have them hooked up in parallel - how do you have the motors wired to them? If the motors are wired in parallel (that is, you are trying to use two shields in parallel to drive one motor for each side - ie, double the current) - does the datasheet for the h-bridge say it can be hooked up this way, and if it does, does the schematic for the shield allow for this?

Have you contacted Pololu regarding this? Furthermore, what are the current requirements of the Dagu Wild Thumper's motors? Do you need that much current handling?

What pins do the GPS shield plug into, and where do you have the RC receiver plugged into on the stack?

Lastly, if you are intending on pulling so many amps, what are you doing about heat sinking the h-bridge IC's?

Are there better designs or resources / examples for designing this?

This book:

http://www.amazon.com/Building-Robot-Drive-Trains-Robotics/dp/0071408509

...devotes a lot of time, attention and math on the subject (without going in so deep you think you need a higher mathematics degree).

hi, i agree that the easier way would probably to extract the images when the thing lands, just afraid it might go off course..but how should i control the camera? i need to send commands to the arduino board. or do i use timers?

I'm not sure how they do it in Malaysia, but generally you can't just release a large weather balloon to fly off willy-nilly without notifying some agency or such (ie - here in the USA it would be the FAA - in Malaysia, probably this: http://www.dca.gov.my/). Unless you want to take the chance of an aircraft hitting your balloon, possibly killing people...

The fact that you are asking such basic questions tells me you have a ton to learn about this subject; you're worried about positioning the camera, etc - but you haven't even thought about permits, sourcing of the weather balloon and helium (won't be cheap!), insulation, heating, and power, the need for various radio comms licenses (ie - amateur/HAM radio), etc.

You will have no control over the balloon - assume it will go "off course" - the best you can do is understand the weather and air currents at the altitudes you plan to fly at, and pick a day with a good forecast. You may or may not be able to control the camera (if you do, you will likely need to use some kind of amateur radio frequency or satellite comms for such control). You likely won't be able to get live video or such from the balloon (again - not without spending a boatload of money on the equipment, which you may or may not be able to recover).

In short - you need to do a lot more research on this project before you build anything - and also gain a handle on what kind of a budget you are likely to need to do this properly, as well as all the other logistics. This isn't something you can generally do as a single person; you will likely want a team of people to help plan, launch and (hopefully) recover. You will need vehicles and people to run them if you do plan on recovering anything. At best, expect to spend a minimum of $1000.00 USD (and that is probably very optimistic) and expect to lose it all on the first launch, with nothing to show for it. If you aren't willing to do this, this isn't the project for you.

so I will need to drain around 6 and 2/3 gallons every ten minutes.
...
The best idea I can think of would be some sort of water level sensor,

You'll want a 40-50 GPH pump to get the water out; 40 GPH will just cut it for your specs ((40 gph / 60 min) x 10 min = 6.667), so you might want to go on the higher end of the scale; this will all of course depend on how high you need to lift the water, which you didn't note. Pumps are rated not just in how many gallons per hour they can deliver, but also how that varies with height. For instance (and this took a bit to find, for some reason!) - here is a pump (PES-80-PW) from the manufacturer of the original Little Giant pumps (LG Outdoor is a subsidiary or brand of Franklin Electric, who makes all kinds of industrial/commercial/residential water handling products - http://www.franklin-electric.com):

http://www.lg-outdoor.com/p/pes-80-pw/decorative-water_water-pumps_mag-drive?pp=25

Note that they show the product specification (just like electronics); it says that this pump can deliver 80 gallons per hour, but only at a head height of 1 foot; at three feet, that is de-rated to 15 gallons per hour. Note the link that reads "curve":

http://mediacdn.shopatron.com/media/mfg/416/spec_file/152573837.jpg

This graph shows all of the pumps in the PES series from Little Giant and how they rate on lift vs gallons-per-hour. You will want to select a pump based on that kind of information; personally, I would stick with Little Giant products, as they are known for their quality - plus they have obvious specs available (a good manufacturer will publish or make available this kind of information - so don't go cheapo with a poorly made knock-off).

Only you know your lift needs - so I can't help you further with a recommendation on the pump, but I am sure Little Giant has something you can use, and it probably won't be that expensive if your lift needs aren't great.

As far as the sensor is concerned, I think that a water level sensor would be best - a simple sensor could be made or purchased that has a float valve mounted to the shaft of a potentiometer (in fact, really similar to the sensor on a automobile fuel pump sender unit); think of something like a float mounted to a rigid arm (you've probably seen automatic valves like this used for swamp coolers) which then is mounted to rotate a potentiometer. You could probably easily homebrew something like this (all it would take would be a piece of stainless steel wire, some kind of float on the end, and mounting it to the shaft of a potentiometer - just keep the body of the pot away from the water as much as possible); it might also be possible to purchase such a thing. Then monitor the value of the pot using an analog input on the Arduino as normal to sense water level changes.

If you need more accuracy - here's an article on how to build a capacitive sensor (this article shows how to do it with a BASIC Stamp - but it should be easy to convert that to an Arduino):

http://mechanical.poly.edu/faculty/vkapila/ME3484/Readings/NV27-Measuring%20Water%20Level.pdf

Once you have your measuring solution selected and/or built - you just need to control the pump (turn it on and off); if you think you have the skills to do so, building the controller as suggested using a solid-state or regular relay is certainly possible; alternatively, you can pick up and use a device called a "PowerTail" or any number of various solid-state relay or standard relay controllers; just make sure the specs of the controller will work for your pump (for most all of the small garden pumps, it should be OK). Also, make sure whatever solution you decide to use, to mount it in some kind of weatherproof box to keep rain and water out of it.

The left and right was controlled by a similar motor as the forward and reverse it was just mounted sideways with a gear. So i assume it would be connected in much the same way as the forward/reverse motor.

Consider it a lesson learned: When doing any kind of reverse engineering, you always need to make copious notes, take tons of pictures (before and after any changes), keep them all in order (very important), and label wires, etc. In fact, it would've been best had you cut the wires to the motors and battery, instead of desoldering them, because then you could easily match colors (and likely polarity, too).

Keep this in mind for the future, and good luck figuring it out!

I'd agree with that. Pins 1 and 14 on the 14 pin SOIC look like left and right (or vice versa) and 12 and 13 are forward/reverse. Stick some wires on those four pins and hook them into four PWM-capable pins on the arduino and go nuts.

I think you're right on the forward/reverse pins - but I'm not sure about the left/right part - it seems like pins 2 and 3 could also be something; maybe if OP could tell us which holes the wires to the motors were connected to, it would be easier to figure out.

That 14 pin chip is definitely the controller, though - analogous to the RX2 half of the TX2/RX2 chipset; I'd be very curious as to what it was originally marked, so I could get a datasheet on it.

Regardless - you still will want to try to identify what the voltage level outputs are of the chip, if possible, once the proper output pins are found. Because if it is outputing 3 volts or less, and you put the Arduino on at 5 volts, you could blow those SMT transistors.