Some time ago, I acquired an Axial A10 Scorpion radio controlled truck. The idea from the start was to turn this into a robot to run around on it's own. (We'll ignore the fun of playing with it pre-robot stage for now.. ). Recently I bought myself an ArduPilot which is a small and inexpensive auto-pilot system. So now I'm trying to get everything running.
First, the truck runs fine. I replaced the battery width only platform with a wider piece of aluminum to hold the battery AND the other components (radio receiver, power control unit (the ECS), etc. Then I added a rear-turn kit so that all 4 wheels swivel when turning. This makes for smaller, more precise turns (and just cuz it was cool!). I ran into a snag with the servos when doing the rear turn kit - the one on the rear would turn the wrong way so I ended up with a crabbing motion to the side instead of a turn (that was still fun though). A quick visit to Action Hobby for some advice and a reversing Y cable (instead of the "standard" Y cable I had), and problem solved. So the truck is now in working order.
Now for the electronics. The ArduPilot needed some header pins soldered to the board. So I added these. Next I needed to connect the board to the computer. Hmm.. I should have read the online guides a little more and bought the FTDI Cable as well. No trouble, Solarbotics is local and had an FTDI breakout board. Placed an order and picked it up the same day. Next, the instructions mention the ArduPilot needs to be powered by the ESC (or the radio receiver), rather than via the FTDI cable. But, the instructions are not clear on what pins should be used (there are differing examples on the web), or the polarity of the connection. It turns out that the board will draw power from ANY of the servo input or output pins (so it seems from some trial and error). AND, looking closer at the board itself, you can see that the outside pin is for the negative lead. But the board seems to be smart enough to handle if these are reversed (again from trial and error).
Ok, so I download the free Arduino development environment (cuz the ArduPilot uses an Arduino chip), connect the FTDI breakout board, connect the power to the board, and then follow the instructions for "loading the code". One note I'll make here - when you make changes to the "libraries" directory (like say, adding in a new library for your project) do yourself a favor and RESTART the development environment (aka the IDE). This is what it took for me to SEE the libraries and get the code to compile. Alas, this is as far as I can get now.
So far, the issues I have run into can be easily written off to PEBCAK (Problem Exists Between Chair And Keyboard). A lack of knowledge and an eagerness to get things running. This is a normal set of issues. But then I ran into an error when trying to upload code to the board:
Binary sketch size: 15510 bytes (of a 30720 byte maximum) avrdude: stk500_recv(): programmer is not responding avrdude: stk500_recv(): programmer is not responding
Having done user support, I know to check for all the usual things before asking for help. There is some mention of this issue online, though I've never seen a solution (yet). One of the suggested "fixes" to upload problems is to use the "official" FTDI cable. Luckily a friend had ordered one last week and it arrived today. So I borrowed that to see if the FTDI Breakout board was the culprit. Nope, I get the exact same error. And through my troubleshooting, I discovered I get the same error on my laptop, so it is not just my computer or the use of a 64bit operating system - my laptop is running 32bit Ubuntu.
After much digging and a lot of trial and error, I had to ask for help (I *HATE* when that happens!). At the moment, the response is to "try it in Windows". I just happened to have installed Windows for the first time in 5 years last week, to a spare laptop drive. Now I'm waiting for the download and extraction of the Audrino IDE on the Windows drive. (Seems soooo odd that Windows needs an 80 MB zip file, while Linux is only a 3.9 MB file. And then Windows takes 30+ minutes to decompress the file??? that's just borked.) After all that, I'm *still* getting the error (though it's slightly different under Windows).
All this seems to say that I messed up the connections, or even the board. So, I'll have to go back to the beginning and step through everything carefully. BUT, when I do get this working, I'll have some cool pictures to post.