In need of clarification...

sherifx

All,

Hello, my name is Sherif and I'm a car design student. With that I should clarify that I do not have any experience with electrical engineering or the more technical aspects involved with microprocessors though I soldered a robot kit once when I was young, though I don't think that'll inform me here.

I'm appealing to you all because I've been up and down the Parallax forums and site trying to decide what I should get for my intended job(s). As a car design student, I'm trying to find new ways to push the concept of vehicles forward and further illustrate some of the more elaborate ideas I have - as such, I think the STAMP maybe what I'm looking for: I would like to experiment with lighting, throughout the vehicle, flashing, pulsing creating effects similar to this dress ( but obviously less complex. Also, I'd like to find ways to make the body panels move, kind of like the BMW Gina concept ( and so forth.

That said, I'm not sure which stamp kit to get. I assume many will suggest the 'Discovery' but I'm not sure if has the ability to drive multiple servos (which I assume I'd need for the moving body panels as well as LEDs), yet at the same time I don't have experience programming... So I thought I would put it to you significantly more experienced people.

I hope I was clear (seeing as its late or early depending on your sleep pattern) and I explained my experience level and intended use sufficiently. If I left anything out - I will check back with some frequency to answer anything and thank you for your responses!


Regards
Sherif

vaclav_sal

Sherif, welcome to the group.

You will find that you get better response from the forum if you have a specific problem.

For starters - try to come up with a real application. Than·you will have a goal to go for.

My advise to you for now - microcontrollers·not only have·limited input / output capability ( as you already know) , however, the main limiting factor is amount of programming memory (out of box).

You need to do more planning in that direction to select appropriate hardware and to be successful.

Cheers

Vaclav

Mike Green

Servos require a control pulse about 50 times a second to maintain their position and Stamps can produce one 1-2ms control pulse at a time and do some other things in between having to generate the control pulses. Things start getting too busy when you have more than 3 or 4 servos.

When you start adding different light patterns, the complexity rises rapidly. You should consider using something like the Parallax Servo Controller to take over the details of managing the servos. It can handle 16 servos, can be expanded to 32 servos, and really offloads all the details of managing the servos from the main Stamp. Download the documentation from the Parallax webstore page for the controller and have a look through it.

The LEDs is another issue. There's not a nice easy solution to controlling lots of LEDs like there is for servos. A Stamp can, with some external transistors, turn LEDs on and off. There are also ways to do dimming of LEDs using external circuitry. This is something that will take a while to learn how to do, the dimming / pulsing stuff at least.

For learning how to use a Stamp and to do a concept demonstration, the Discovery kit will work well. It can control 3 or 4 servos easily by itself, more if it's just a matter of moving one or two body panels at a time and leaving them in the new position while something else happens. You could also turn LEDs on and off using external switching transistors as shown in the tutorials that come with the Discovery kit. You could also learn about dimming LEDs.

sherifx

Thanks you guys, I appreciate the feedback. I understand the need for defining what I need for the project first before figuring out what you need, but I don't know, nor would I based on the ideas I have lol! I think I will take Mike's advice and explore the Discovery kit. I'm a very hands on type of person and the more I can explore the more ideas I will get, from there if things get more complex I can build and plan accordingly. Right now I imagine I'll build the vehicle in a 3D program like Alias, 3D print the parts with hinges and the position the servos to mobilize the body parts. As far as driving LEDs I'll keep searching.

Thanks for the feedback guys!

Mike Green

Maxim has a line of LED drivers that allow you to drive as many as 16 LEDs per chip with individual control of LED brightness and you can have several chips on the same I2C bus. para.maxim-ic.com/en/search.mvp?fam=expanders&hs=1 You have a lot to learn before you'll be ready to deal with this sort of complex device, but I mention it to show you what can be done. The BS2p Stamps have built-in I2C commands, but you can also handle I2C devices with a BS2. There's a Nuts and Volts Column on this subject (? #85).

Do explore the Parallax tutorials and the Nuts and Volts Columns. The Resources tab on the main Parallax website is a useful link to these as well as other resources.

sherifx

Mike - thanks again. Seeing as I understood part of your message, I'd say your assessment is correct; I do have a lot to learn. That said, I look forward to the Discovery kit and exploring with the servos first and foremost as these have the most promise and excitement for me. I'll certainly check out the resources you suggested - its always nice when someone is fresh to a new to a subject when others offer a helping hand, so thank you.


Regards
Sherif