# Question/Help about new project

Hello,

This year I've obtained new project for my univeristy and since the corona situation, libraries/professors weren't that much available... which is why Im gonna ask for some help here if possible, if anyone is able to give me any kind of an advice.

Basically I have developed a certain structure in a shape of 'umbrella' that uses origami techniques in order to open sucessfully. It has a stepper motor inside with values of 12V and 1.3 A. I have sucessfully made a part where it opens and closes without any issues. Next step of my project is to supply the motor with a battery that is being charged with solar cells strapped on the top of a structure, rather than power supply from an outlet like it is used now, basically I need to make a system thats gonna charge battery and have enough of supply in order to make motor open the construction once sun is detected and close it down once its gone (in shade)(whole process of opening lasts approx 5-6 seconds, which means the motor won't be used much in best case scenarios). After exploring a lot which parts I need I came up with an idea of using 3.7v Li battery with 3800 mAh, battery charger that has DC-DC boost (which will hopefully be enough to start motor and supply it with 12v even tho i'll be using 7.4 V batteries (x2 in series) and a photoresistor in order to detect sun/shade, Im trying to think if there is anything else I could use in order to improve this or my idea of this working out is not even possible, sadly I am not an expert in this field but beginner-intermediate so any kind of a help would be appriciated.

Thank you all for reading and helping out!

Stepper motors are typically on all the time, and typically power hungry.
Both of those mean they are a poor fit for solar power applications. Not impossible, but an additional challenge.

A geared, brushed motor with an encoder would do the same job, be less hungry while in use and would draw no power when not moving.

I am shocked to see a university project being designed based on "hope". Measure the current needed to start and run your motor. Take the "hope and prayer" out of your research.

Paul

vinceherman:
Stepper motors are typically on all the time, and typically power hungry.
Both of those mean they are a poor fit for solar power applications. Not impossible, but an additional challenge.

A geared, brushed motor with an encoder would do the same job, be less hungry while in use and would draw no power when not moving.

My design is base on an axle that came with a motor, throughout google I couldn't find any brushed motor with an encoder and axle that is around 30 cm long. I will definetly continue looking for it, maybe I come up with something similiar, thank you for the advice tho!

buzzol, do you have a link to the motor with the specific shaft that you purchased?
If so, post it here. It might help to have others see what you are using and offer suggestions to other motors that might work.
Also, pictures.
Your project is intriguing and I would like to see it.

My design is base on an axle that came with a motor, throughout google I couldn't find any brushed motor with an encoder and axle that is around 30 cm long.

It is trivial to connect an axle to a motor shaft. There is a shaft coupler for any conceivable combination of shafts. So pick the best motor to do the rotating and the best axle to carry out the task.

Start here for examples. McMaster Carr has everything else.

vinceherman:
buzzol, do you have a link to the motor with the specific shaft that you purchased?
If so, post it here. It might help to have others see what you are using and offer suggestions to other motors that might work.
Also, pictures.
Your project is intriguing and I would like to see it.

Yes, 'Stepper motor NEMA 17 with axle 3A101' that would be the motor.
Picture wise I have nothing that shows it fully assembled but more or less the way electronics were connected, soldered inside the consctruction. When I get a chance I'll do few pictures of how it works and post it here.

jremington:
It is trivial to connect an axle to a motor shaft. There is a shaft coupler for any conceivable combination of shafts. So pick the best motor to do the rotating and the best axle to carry out the task.

Start here for examples. McMaster Carr has everything else.

I will check that out also and see if I can find a better solution motor wise !