Running multiple sensors with BS2?

Shadowcasterx4ffc

I'm having some problems with BS2 programming. I'm not entirely sure how to make multiple programs and sensors·run at the same time using a single Board of Education. I'm trying to control a fan (using a temperature sensor)·and a light bulb (using a light sensor) with an RC4 board, which is hooked up to the BoE. We're not having problems with the RC4 or BoE, it's just the coding itself.

Ugha

First, I'm not sure what an RC4 board is so this may not apply to you:
The BS2 can only do one thing at a time.

So you have to figure out a way to do everything you need to at once.

I'm hoping your using some kind of relay or H-bridge to control your fan.
Otherwise it could seriously damage you stamp.

Get back to us on how your fan/lightbulb is setup.

Is the RC4 board some kinda relay board?

Shadowcasterx4ffc

Yeah, the RC4 is a relay board.

I'm working on a greenhouse with some other guys at school, so we need to be able to run multiple sensors such as temperature, light, and moisture, so we can control sprinklers and lights.

Thanks for the help anyway.

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-Eugene

Greenhouse Project

Ugha

This is the basic concept you should use I guess, written in pseudo-code

Have two bit variables... lets say its named Fan and Light

Start:
Check temp sensor
if temp is too high and fan = 0 THEN turn on fan
else if temp is too low and fan = 1 THEN turn off fan
check light sensor
if light sensor is dark and Light = 0, turn on light
if light sensor is light and Light = 1, turn off light
pause X
goto start

That's the basic flow I'd use... you need a loop that will do the sensor checks and execute the shutons and shutoffs
of the relays as needed.
The pause X is because you'll need to play with this number and see what a good pause time is. I'm afraid that if
its too low then the fans/lights will flicker as they reach the detection threshold you set.
Also remember that you need to have the light sensor far enough away from the bulb to not be triggered by it.

If you need actual code, I can supply you with that, I'm just in a bit of a hurry at the moment.

Disclaimer: I'm a newbie, taking my advice may be hazardous to your health(electronics).

Shadowcasterx4ffc

Thanks. I'll see if I can get the actual code up tomorrow.

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-Eugene

Greenhouse Project

Lee Harker

Well your view of "at the same time" and the Stamps are a bit different. It is true that the Stamp and most other processors can perform only one command at a time. Fortunately, it performs them so fast that it appears in most cases that they are happening at the same time. In your particular case, you could easily control a light and fan and read a few sensors in plenty of time to handle a greenhouse. The reason is that the temperature and other conditions will not change that much in a few milliseconds. Your readings could be·monitored once·every second and the Stamp would spend most of its time waiting for the next job to do.

Shadowcasterx4ffc

Well, it's gonna be getting it's jobs to do. We have a solenoid to control the water flow, as well as the fan/light for simulated wind and light. I supposed we're also gonna have a heater, so it should have enough to do.

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-Eugene

Greenhouse Project

Ugha

The BS2 should handle all that fairly easily.

Do you need anything else from us?

PS: I love your avatar image.

Shadowcasterx4ffc

I'll get back to you guys tomorrow on it. I'm not the one who actually does the programming. I take care of anything outside of programming (as we haven't started building yet) such as this. I actually joined up because we're basically at a standstill with the project right now. We don't have the tub for the dirt for the greenhouse so we can't start building yet, and we have this issue that I posted here. We also need a USB serial adapter for the new laptop that we just got, and we're waiting on a crapload of new sensors from Parallax. The ones that we're using are the little tiny ones that are less than a square centimeter big.

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-Eugene

Greenhouse Project

Shadowcasterx4ffc

I had the coding guy try your idea, but he still can't get it right. If possible, can we have some code for this? Thanks.

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-Eugene
Greenhouse Project

RDL2004

I would highly recommend that your coding guy download and read the documentation for "Process Control" and "Industrial Control" from the Stamps in Class series. They are free downloadable pdf documents and are available from this page:

www.parallax.com/tabid/535/Default.aspx

If you are new to microcontrollers you might want to start with "What's a Microcontroller" first.

What you're trying to do is actually fairly easy and is something that Basic Stamps excel at.

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- Rick

sam_sam_sam

Shadowcasterx4ffc

Do you have the Demo Code for the RC4
If you do not here is the Demo Code

I· would run the demo code for the RC4 first and understand how to control it
Then run the Demo for the Temperature Sensor that you are going to use and learn how to control it
Then run the Demo for the Light Sensor that you are going to use and learn how to control it

Once you have learn·how to control each item then write a routine that check·each sensor and base on the set point that you have for·each sensor will turn that relay on then go back to the routine and check the sensors again

I have found until you have a good understanding of the sensors that you are going to use it is very hard to get a routine written that will work
Ugha has the right· ·here


Ugha
·
Start:
Check temp sensor
if temp is too high and fan = 0 THEN turn on fan
else if temp is too low and fan = 1 THEN turn off fan
check light sensor
if light sensor is dark and Light = 0, turn on light
if light sensor is light and Light = 1, turn off light
pause X
goto start

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··Thanks for any··that you may have and all of your time finding them

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Sam

Post Edited (sam_sam_sam) : 3/8/2008 6:34:03 PM GMT

trini4life

I am building a device that uses 2 GP2D12 distance sensors. It will measure the thickness or width of an object placed between the sensors. I need to find a way using PBasic to have the sensors turn on and off alternately. One turns on for 50ms then off, then the 2nd sensor turns on for 50ms. Any help would be greatly appreciated.

Colt

·· I used something similar to control a travel refrigerator, I'll attach the code. It's not the final code, but just a basic program. Some of the stuff in the code isnt hooked up or tested, but you'll get the general idea of what is going on. When the temp reached a certain setpoint it would cycle the cooler on and off. I ran the code for a month or so, just controling the cool cycle· ( on and off ) and it just exactly what it was supposed to do.·· Adding more sensors shouldnt be any big deal, just think it out...

Shadowcasterx4ffc

Thanks guys. I'll have the guy check it out when we get back to school.

Anyway, I don't think we have the demo code.

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-Eugene
Greenhouse Project

Post Edited (Shadowcasterx4ffc) : 3/10/2008 4:40:08 PM GMT