Building the 50 dollar robot, lots of questions :S

[Slimmeh]

Theres a few vague/uncovered parts in the guide that I'm a little unclear of, and I don't want to mess things up. I really don't know what I'm doing, I'm just following the tutorial to learn.

1. If I'm using a 9v battery, I need at least an 18v capacitor right?
2. Anyone know a store I can buy a serial-to-USB adapter from? I could just plug it into my desktop, but I would much prefer to use my laptop. I checked office max, best buy, and radio shack (online.)
3.
That's the multimeter I have. I'm not sure where it's from or anything, I just found it in my dad's garage. I read the manual, and found out from it to test the resistance (for the photo resistors), I use this section.

But which number should I use? Also, when I turn the multimeter on it displays "1". When I put the prongs to the prongs of the photocell, it cycles through a few numbers 500-900 for a few seconds, then just displays 1 again until I take the prongs off and put them back on.
4. Also, anyone know where I can buy the little thing to connect a 9v battery to?
5. I have seen websites to buy HDPE from, but does anyone know a store that sells it? Like home depot, etc.

[izaktj]

Check how I connect mine.

[gamefreak]

The 1 means it is maxing out on resistance, which is good if the prongs are touching nothing, but if the prongs are touching anything metallic and it says one then you either have it set to a resistance much to low, or it is broken.

You can buy 9 V bolt connectors at Radioshack, I would try the internet to get a serial-usb adaptor

[Slimmeh]

Check how I connect mine.

I also have that exact multimeter, so I'll use it and use that setting.

And what about 1? Will I need a 18v capacitor? I only have a 16 volt one and it'd be a bitch to order another (not really but I'm lazy.)

[gamefreak]

that setting is wrong for ohms, that is DC voltage, you need the one below it, with the horse shoe.

[HDL_CinC_Dragon]

Technically its an Omega rather than a horseshoe but im willing to get you knew that already. Im just being a jerk

@Question 1: A 16v cap should be ok. I wouldnt go too much lower than that though.
@Question 2: I dont know if youll be able to find a Serial-to-USB in any big name stores. If Best Buy or Radio Shack didnt have it, Im not sure if youll be able to find it in a store at all. Try to find some no-name computer stores in your area. That may be youre best bet. Sometimes divy looking stores can have some pretty sweet stuff as far as computer stores go. If not, google it and try to find your best offer :-p
@Question 3: A rule of thumb for that sort of thing is always start at the highest number. If your DMM barely responds then go lower until your getting all digits saying something other than '0'. You probably wont need anything higher than the "20k" setting but im not sure what youre working with :-p a "1" means over range so if your trying to measure under something thats 3000ohms and you have your DMM set for 2000 it will give you a "1". Photocells can be tricky if you dont keep them absolutely still in a perfectly stable light environment. If your moving it around or have like a strobe light on or something lol that would cause it to jump around a lot.
@Question 4: As stated above, radioshack has those snap connectors that I think youre looking for. You can get a bunch of em pretty cheap.
@Question 5: A lot of cutting boards are made of HDPE. Try going through the kitchen ware sections of stores like K-Mart and Walmart. You might even find some in dollar stores.

Hope this helped!

[Slimmeh]

Ya I checked best buy and radio shack online for the serial port thing, I'll just order it from a site, I don't really think there are no name computer stores near me. The photocell was probably moving a little, I'll restrain it. I couldn't find the HDPE at K-mart, Walmart, Lowes, or Homedepot, I'm just going to order some online. Found the 9v thing at radioshack.

That's all for now, thanks a lot. I will probably have more problems whenever i have the time to work on it.