Help with handheld device that uses a motor, 2 lasers, photoresistor, LED

I’m working on a project that will turn a small motor on or off, depending on the light level detected by a photoresistor working with an LED. The motor will need to be strong enough to turn a small spool of paper, and I plan to use gearing as needed to reduce the speed of the motor to about 60 rpms. The project will be enclosed in a small handheld device, so all components need to be as small as possible. The device will also include 2 small lasers to help align the device.

I’ve got the arduino sketch working how I need it to on an arduino uno using usb connection and a 9v battery powering a small hobby motor, but I’m having a hard time figuring out how to best provide portable power to the project. Ideally, the device will be run off batteries, but if needed, a plugin adapter could be used. So, my questions are:

  1. Is it possible to run all of these components using a 9v or 2 AA batteries, and if so, how?

  2. Could someone help me pick out a motor that would work for this project? (i.e. low power, small, slow, inexpensive, but able to turn a spool)

  3. Any recommendations on inexpensive laser diodes that will work with my power requirements? They don’t need to be very powerful.

  4. Is there a way to cut the size of the arduino, since I’m only using a few pins? Maybe using the mini or nano?

I’m new to the arduino and electronics world, so any help would be greatly appreciated.

Thanks in advance!

gggbarry: 1. Is it possible to run all of these components using a 9v or 2 AA batteries, and if so, how?

You are not going to get much out of a 9V battery. AAs will work from your statement above.

  1. Could someone help me pick out a motor that would work for this project? (i.e. low power, small, slow, inexpensive, but able to turn a spool)

You can search any online market, but try Sparkfun and Adafruit. But since you are the one having to mount it, only you would know what you need.

  1. Any recommendations on inexpensive laser diodes that will work with my power requirements? They don't need to be very powerful.

I always used those cheapo laser pointers from department stores. Easy to hack.

  1. Is there a way to cut the size of the arduino, since I'm only using a few pins? Maybe using the mini or nano?

Pro Mini or Nano would work. If you're brave, you could try the ATtiny series controllers and make your own board.

Hi Codlink,

Thanks for getting back to me so quickly!

So, I have a couple of follow up questions if you don't mind.

You mentioned using AAs. This is probably a basic question, but how do I power the arduino with them?

I'll do some more checking for motors. I've done some research, but haven't had any luck finding motors that meet my needs. I guess I'm looking for help on a type of motor that has power requirements that might make my project easier to power. I'm pretty sure I can get it mounted if I can find one that meets my other requirements.

Good idea to use the laser pointers.

Using an ATtiny might be beyond my capabilities, but I'm going to look into it. Can you tell me how these are programmed? Is it similar to programming an arduino?

Thanks again!

You could actually get AA holders that have wires terminated with the barrel connector that will fit into the barrel jack of an UNO. But to power a Pro mini or nano, you would need to solder the wires directly to Vin and GND.

Like this https://www.sparkfun.com/products/9547. There are also other holders with more capacity.