Im working on a project but i’ve only began learning to use any of these. My objective is to control this motor {https://catalog.precisionmicrodrives.co … 8-3mm-type} with my phone, I’ve determined that I have to use a bluetooth module {https://www.sparkfun.com/products/10253} and this Arduino{https://www.sparkfun.com/products/11114}. Ok so i need help knowing whether these parts are compatible and how to put it together. And whether 4 3v coin batteries would be sufficient for all three devices. THANK YOU SO MUCH FOR THE HELP
All 3 work on 3(.3) volt, so that should not be a problem. But the arduino board cannot directly drive the motor. Atleast not to it’s full power. You would need an additional transistor to amplify the current out of the Arduino pin. This one should suffice:
https://www.sparkfun.com/products/521
Proper switching of a motor, which is an inductive device, would also require a diode across the motor (reverse biased) to equalize the voltage spike when turning of the motor. But it may not be that significant with these low currents (<100ma). This one is small and sufficient for the job. https://www.sparkfun.com/products/8588
A pulldown resistor is also advisable, to pull the base and pin level down in case the pin is accidentally configured as an input. You would want the motor to turn off then. 10 kOhm should be good.
As for the batteries. 3 volt coin batteries usually cannot deliver much current due to relatively high internal resistance. Is that the reason why you want to use 4 of them? To share the current load. How did you intend to connect them? Each device 1 coin? Or in some parallel configuration? Please share your thoughts. The bluetooth module takes quite a lot of current (40-50 ma). And the motor double of that. I’m not sure the coins can supply sufficient. They usually are made to supply less than 1 ma.
The coin batteries would be in a vertical configuration and the reason I wanted to use them was because I have a very limited amount of space to work with so I have no idea how to make this work with a battery the size of a a 9V.
I feel like I would be asking for too much if i asked for help with being shown what gets connected with what but if i didn’t my answer would always be no. Anyways thank you Valen for your support and response I really appreciate it.
I feel like I would be asking for too much if i asked for help with being shown what gets connected with what but if i didn’t my answer would always be no. Anyways thank you Valen for your support and response I really appreciate it.
[EDIT}Vertical configuration does not mean anything in the world of electronincs. It also depends on what the battery-holder looks like, or how it is mounted, to have any meaning. Aside from that, gravity has barely any effect on the flow of electrons. What do you mean with ‘vertical’.
Using the coin cells in [EDIT:whoops, not parallel] series (so each one in-line behind the other, instead of next to one another supporting shoulder-to-shoulder) would get you above 9 volts or so. But why would you want that? All parts that you have mentioned work around 3 volt. If you intend to provide enough voltage to supply the RAW powersupply input, then you are simply wasting it in linear voltage regulator. Burning 2 or 3 cells in terms of voltage away as heat. Using a 3 volt step-down switching regulator bord would probably be more efficient, to directly supply the arduino Vcc or 3(.3) volt line.
Also, as soon as you turn the motor or the bluetooth module on the voltage will drop anyway. Current draw will cause some of the battery voltage to disappear due to internal resistance. Which is, as I said, fairly high for lithium coin cells. This is in the order of 10s of ohms or more. You can calculate how much a drop of 100 ma (atleast motor and bluetooth simultaneously) will amount to.
Not knowing of any other concerns of your project, I think this kind of battery is more appropriate for the kind of current draw you will experience, than the coin cells. But it requires appropriate charging system. https://www.sparkfun.com/products/731
I have very little knowledge about electrical engineering or electricity for that matter so to me Vertical configuration meant stacking the batteries and attaching a wire to the positive and negative end. But that doesn’t matter but the facts you’ve made me aware of make perfect sense and I will definitely be using all your suggestions. Im gonna be ordering all the parts and all I would need help on would be putting all the parts together (Ill worry about programming the arduino later)
Parts:
The motor-
{https://catalog.precisionmicrodrives.co … 8-3mm-type}
Bluetooth modul-
{https://www.sparkfun.com/products/10253}
Arduino-
{https://www.sparkfun.com/products/11114}
Diode-
https://www.sparkfun.com/products/8588
Transistor-
https://www.sparkfun.com/products/521
Battery-
Don’t forget a charger. These batteries cannot simply be connected to some charging voltage and be left on their own. The voltage and current need to be regulated in a specifc way.
In what way?
Google lithium ion or polymer batery charging. A combination of constant current and constant voltage regulating.
Ok i’ve ordered all the parts and now the only thing I need help on is putting it all together. Could you, kind sir, be able to assist me in such a task?
Don’t put it all together at the same time. Do it in small steps, that you can understand and oversee. If you do it all at once you will not know where to begin to make it work. Or find where the problem exists.
Learn to use the arduino to make one of the leds on the board (often pin 13) go on and off.
Then learn how transistors work.
And how you should wire them up with a motor and the diode.
And how to switch it on by changing the voltage on one of the Arduino output pins.
Leave the bluetooth module as last. It is complicated compared to the rest. Also I don’t have have one myself. So I can’t guide you with this part. You haven’t even said what you need it for.
Only once you can do and understand each individual part should you consider putting it all together. Then you will also have a bit more programming knowledge. I hope. I fear you have commited yourself to a project that is too complicated for you now. Use the internet to find tutorials on how to use the different parts. Sparkfun has a special section with tutorials, that could explain it better than I could in these short forum posts. But I will help if you have atleast tried something on your own, and don’t understand why it is not working.
https://learn.sparkfun.com/tutorials?page=all
Even though you do not have all the parts of the Sparkfun Inventorers Kit, some examples in it’s guide would help you.
I noticed there weren’t any resistors in your shopping list. Make sure you have an assortment of various values of them. You need atleast 1 (a few kilo ohms) to restrict the current through the transistor base. And maybe 1 for safety to pull the voltage of the base to GND. But you can never have enough (different) resistors to play around with them. Atleast to learn how voltage dividers work.
https://www.sparkfun.com/products/10969
Also more tutorials:
by one of the Arduino creators:
Alright I’ve already started experimenting and learning about the parts and how they’re gonna work together, but in the near future I may need help, if something doesn’t work.
Ok ive got a question. Since the Arduino requires a voltage of 3.3 v and the battery supplies 3.7 v its impossible to power this LED( http://www.radioshack.com/product/index … =CT2032233 ) because it requires 5v. Right? (BTW this isn’t related to the project this is just me learning)
Could the LED be powered if its connected to a transistor and than a resister to protect from the excess volts?
No, that is the maximum voltage when the LED/diode is still blocking, or about to break down due to reverse bias. It means the cathode (-) is 5 volt higher than the anode (+). More voltage and it starts to leak more current. Below this voltage, only a minute amount of current flows.
The forward voltage drop (making the led light up) of a red LED is usually around 2 volt. The anode is at a higher voltage than the cathode (making the led light up). You can easily power it with a 3.3 volt output pin. But you must limit the current with a resistor that drops the 1.3 v excess voltage. (3.3- 2) For a normal current of 20 ma you need atleast a resistor of (Oops) 68 ohms. Less current and more resistance is probably still bright enough, depending on the ambient lighting.
here is the datasheet:
Alright alright, this is making sense. But on the Arduino Pro Mini how would i know where the power and other devices are imputed? There are just spaces for pins but which do i connect to the power source?
I partially answered my own question already with this picture ( https://dlnmh9ip6v2uc.cloudfront.net/as … 000000.png ) but why are there 3 inputs for voltage?
