Science project feasibility

Using Arduino Project Guidance
#1

Hello everyone,

I am completely new to arduino but was recommended by a friend to use one of the platforms to build a prototype for a simple (in terms of low input/output and programming) "stimuli" producing device.

We currently use 6V 10Ah batteries to power all of our devices. I know this voltage is a bit low but perhaps I could step it up?

The only input would be a photocell that would trigger 4 flashing green LEDs at night.

Other outputs would be 3 small fans (5V, .18A, 20 mm x 20 mm) and 2 small speakers (.1 W).

I would also like to produce a small amount of heat (~100F), I'll just experiment with some resistors.

The only thing that would be on continually would be the LEDs and those are only on at night.

The fans would "burst" about every 2 hours but they would not need to burst simultaneously, they could do it in succession (less current draw).

The speakers would produce an irregular beat, at most just a tick tock/click/heartbeat (~40 BPM) and these wouldn't be on all the time.

I know it sounds wacky but I'm trying to produce irregular stimuli. I'll have a 24 hour program.

Well, I think I'll just buy an UNO and start tinkering!

#2

At the beginning I thought you wanted to stimulate somebody to program . . . . :sweat_smile:

You have no big needs; concerning on the # of inputs (1) outputs you need an uno is enough. You will need, of course, some hardware to move the fans, generate heat (whatever you are going to heat -What's 100F?-), etcetera.

I can't tell you about the best way of generating the sound: sure if it is not concurrent with the other stimuli (and if it is, too, but it complicates a bit) and is a simple wave (square -the easiest- sine -not complicated- several armonics -complicates a bit-) you can generate it using a board that has a DAC (digital to analog converter; if it is square even an arduino uno will do, but a square wave maybe "too" stimulating, I think ;)) and additional hardware to amplify the signal (and a speaker!). Alternatively you can use an external specific chip to produce the sound when the arduino (uno) tells it to do it.

Regards

#3

What's 100F?

100 degrees Fahrenheit.

#4

ahobbes:
We currently use 6V 10Ah batteries to power all of our devices. I know this voltage is a bit low but perhaps I could step it up?

The opposite actually - it is a bit high for an Arduino which runs on 5V. Raising the voltage only to regulate it down again is not a good idea (particularly using the internal series regulator which simply wastes the excess voltage). What you need is a really LDO (Low DropOut) regulator to condition that for the Arduino - which could tolerate a drop to 4V or so if no attached device is otherwise critical.

5V will operate single LEDs just fine - you need some sort of current control, at least a resistor for each one.

#5

100 degrees Fahrenheit.

Those imperial units! :wink:

#6

I would also like to produce a small amount of heat (~100F), I'll just experiment with some resistors.

A relay with a 6V automobile bulb and a temperature sensor should do it.

#7

steinie44:

I would also like to produce a small amount of heat (~100F), I'll just experiment with some resistors.

A relay with a 6V automobile bulb and a temperature sensor should do it.

volume of the space and heat gain/loss was not specified. a resistor could do it...a small length of nichrome wire perhaps ?. also not specified is if light would affect the project.

#8

volume of the space and heat gain/loss was not specified. a resistor could do it...a small length of nichrome wire perhaps ?. also not specified is if light would affect the project.

If not specified, then why reply?
It's only a suggestion.

#9

Awesome, thanks everyone for the advice!

I do not want to introduce any light other than the green LEDs. I could cover the light bulb up with black paint perhaps. Great idea about the temp sensor - this could be used to introduce some variability, I will experiment! I will be using a black enclosure and ambient temps here stay well below 38C (100F) :stuck_out_tongue: A small flash light bulb's heat would certainly be visible enough through IR. SO, heated area isn't too important, I just need visibility (imagine if you were looking at a human body through FLIR but scale this down to insect size - if that makes sense).

As this is the first iteration of this project, I went ahead and bought this.

The Pro Micro - 5V/16MHz: https://www.sparkfun.com/products/12640

The input voltage is 5 - 12V (as opposed to 7 - 12V for the UNO), so I should be fine with my 6V battery, I think, I hope. The number of inputs and outputs will suffice for now (gonna hold off on those fans). Thanks Paul, for the advice on voltage. I noticed if I didn't put resistors in my 555 timer circuit (when I swapped the speaker out for an LED), the LED glowed yellow when it wasn't green and got quite hot (hmm).

The main thing I want is variation of all of these outputs. Maybe one speaker will be making a simple heart beat (square wave), while the others are doing something else (varied beats, no music necessary, although good idea - perhaps I should look into a recording to fit my needs). In the mean time, the LEDs will be alternating slowly (every 5 minutes). Occasionally, all of the LEDs will turn on (need to generate varied shadows).

My first go at this was a simple 555 timer circuit and a tiny speaker from radio shack. Here is where I got the idea:

It turned out perfect! A nice "thump, thump". But, I need some variation (like I said). A vibration here, vibration there. Change in beat, etc.

Shouldn't be a problem to reproduce this with an arduino I figured.

So I received all of my hardware: a ton of green LEDs (bright and diffused), a photocell, a tiny transducer (good for making vibrations), a couple of tiny speakers (8 Ohm, .1W), my arduino compatible Pro Micro (SparkFun) and a few jumpers and such

If you can guess what the purpose of this project is, you're pretty cool! Again, thanks everyone - you're giving me some great ideas. I'm quite excited to tinker with this all night.

#10

Shouldn't be a problem to reproduce this with an arduino I figured.

Well, if the sound from a square wave is not squezzing and/or unpleasant I would use it. I'd keep the 555 taking care of it, as long as you need just one frequency. If it's the case, just use a digital output to switch the 555 off-on.

I'd not make a guess on the purpose. I don't dare . . . . . . :grin:

Regards

#11