Project Shopping List Help

Hello all, I am very new to Arduino, the language and the hardware needed with a project I would like to try. Any help is much appreciated.

I would like to measure the movement of a bar, then using this information calculate the speed, force, and similar measurements. I believe my project would best be suited for a string potentiometer, I would attach the string pot to the bar and once the bar is lifted, have the data sent to my computer for analyzing. I will attach the string pot to the bar with a clip or something similar. The bar should travel in one plane of motion (from ground up) with very little swaying front to back, I do not know that the swaying is important, but worth noting.

The string potentiometer I am looking at can be found here -

I believe I am suited for the ARDUINO STARTER KIT MULTI-LANGUAGE set, and I am hoping I can use a USB to get from the Arduino to my computer.

Before I start to think about coding and formulas, are there any other recommendations, hardware wise, that I would need or you would suggest?

Sorry for the long post, again I appreciate any input.

Your post was MOVED to its current location as it is more suitable.

Could you also take a few moments to Learn How To Use The Forum.

Other general help and troubleshooting advice can be found here.
It will help you get the best out of the forum in the future.

Are sure you want the pot attached to the bar? Why not fix the pot in place and attach the string/wire/cable to the bar?
Paul

Cool device. I note it features

Resolution: Theory of infinite

A bit pricey though, for grabbing one to play with.

Have you considered other means to determine the displacement you are hoping to measure?

a7

Sorry, that was poor wording on my part. Yes, that is the plan, attaching the cable to the bar with a clamp of some sort, the actual unit will be secured to the floor.

Hopefully a typo on that resolution?

I have not down too much research on other methods, accelerometers and gyroscopes would be another option I suppose? Would those be compatible with an Arduino?

Or bad translation. Let’s hope it means theoretically infinite resolution, which is probably what would be claimed of an ordinary potentiometer. Obvsly the actual resolution will depend on your choice of A/D converter.

The Arduino UNO has 10 bit a/d build in, but you can get chips or modules and with a bit of care get higher resolution. They are easy enough to to use from the software point of view. If you start coding and experimenting the internal a/d can be enough; if you anticipate wanting more, then code your use of a/d conversion using a function so you can easily swap in other devices to test.

But tell us more about the problem. How big/heavy a bar, how much movement, what control,s how it moves, what exactly data are you hoping to acquire at what rate, what moves the bar how fast &c. &c.

Hard to say what alternatives might work until we know more.

I’m just thinking there might be a cheaper solution that is as good or very close enough.

It’s possible the string pot is the best - it’s your budget and trade-offs though, not mine. :wink:

a7

Thank you for getting back to me alto.

Ive looked more into accelerometers and gyroscopes and I am thinking that you are right, for the price and for just getting started, this may be a better option.

I am hoping to attach a unit to a barbell for weight lifting to measure the movement of the bar from the starting position through the movement then back down to the starting position. I am hoping to measure velocity and distance traveled and then calculate force. The bar alone will be 20kg but with weight added it could be up to 200kg or more. Each movement will last between 2-15 seconds depending on repetitions. The bar should travel 600mm at most.

I am thinking a ARDUINO NANO 33 BLE may be a really good option as I could attach this board to the bar and have it send the data to my computer via bluetooth. From my understanding this would be the accelerometer/gyroscope/board all in one?

Sorry to switch up paths so quickly, I am glad I asked.

Accelerometer.

I would connect an accelerometer with a Nano or an ESP8266-01 powered by a coin cell. Lowest weight on the barbell. You can connect the ESP over WiFi to a PC to record and interpret the data.

Start by getting an accelerometer (or two- they are cheap) and a Nano (disclaimer- I've never used a Nano), and experiment.

Thank you SteveMann,

Is there an advantage to getting the Nano and attaching an accelerometer vs buying a Nano 33 BLE where it has the 6 degrees of measurement built in?

I have been looking into a power source for the Nano 33 BLE and am hoping to incorporate a rechargeable battery.

I think I would need to purchase this -

As well as a lithium ion battery.

Does that seem right?

Thank you!

I’ve used that system before, lipo battery and boost regulator. It works very well.

An advantage to the unit with build-in 6DOF is… no wiring, more compact and perhaps more immediately relevant and useful example code.

Look at this

They work well, then a button can power you ON and OFF also the Arduino can use an output line to reach over and turn itself off.

Place the power switch like this between the battery and the boost. When off, very little current will be drawn from the battery.

You can parallel the on board pushbutton with another pushbutton of your choice if the physical arrangement requires.

HTH

a7

Awesome, I truly appreciate all the responses, I think I am ready to dive in.

Arduino Nano 33 BLE - Accelerometer/Gyro/Board
Lipo battery - to power everything
PowerBoost - to boost 3.7V lipo battery to 5v power Arduino
Pololu Mini Pushbutton - on off button.

Ive been looking at the rechargeable battery situation for the past few hours and am wondering what you used in the past to recharge the lipo battery? A few resources say I would need a special charger, that I cannot just plug in USB to a computer or to a wall.

Thanks

I use LiPo, lithium polymer, batteries or single cells and have a purpose built commercial charger for that specific chemistry. But meant for larger cells and batteries. And $$ not cheap.

Lithium cells and LiPo in particular are kinda scary fussy about use and charging. Small capacity cells aren't so bad but should still be treated according to standard wisdom.

Here's a simple cheap charger only thing:

and you will also come across some very tempting devices, charger + boost, for example:

That's just google for you. I have not used a combo unit, so I do not know if they have a switch and/or very low power mode like one would obtain using a Pololu switch and a regular boost.

You could also look into using 18650 cells and chargers that match. A very popular cell.

BTW one can make a circuit functionally equivalent to the Pololu device fairly easily out of a few MOSFETs and resistors. I have not done that. If I ever had 1000 of something made I would.

a7

Okay great, I did see the Adafruit device you posted. But also came across many other larger charges that were recommended and was not sure, so thank you.

So if I wanted to create device in a small housing (to attach to a bar) it would look something like this:

Nano 33 BLE > MicroUSB to MicroUSB cable > Boost > LiPo via JSP connection on battery. With this set up I would need to detach the JSP connection from the Boost and connect it to the Adafruit charger separately to charge?

But I could also do:

Nano 33 BLE > MicroUSB to Micro USB cable > PowerBoost > LiPo via JSP connection on battery. With this set up I would not need to disconnect the JSP connection from the PowerBoost to charge the battery as it would be connected to the PowerBoost, which has the separate USB port for charging? Preferred method if reasonable

Edit: As I continue to look, it seems like I have mixed up the USBs for this device. Maybe it goes:

Nano 33 BLE > USB A to MicroUSB > PowerBoost > etc... and the extra MicroUSB on the PowerBoost would be used to charge the unit. The USB A would need to be soldered.

And to add in the Botton switch you recommended earlier, the set up would look like:

Nano 33 BLE > mUSB to mUSB > Boost > 150mm jumper wires (soldered) > Pushbutton > LiPo via JSP with the Adafruit charger separate.

or

Nano 33 BLE > mUSB to mUSB > PowerBoost > 150mm jumper wires (soldered) > Pushbutton > LiPo via JSP.

I am sure there are more ways to do this but if I were to purchase the above listed products I should be headed in the right direction?

Again thank you all for your patience with me!

NP, this is fun.

You should can power the Nano with 5 volts directly to the appropriate pin, not through the USB port.

Also, I suggest you arrange your steps carefully. I would forget all about the form factor, battery, charger, boost regulator and switch. For now.

Those are easy problems, not really any kind of deal-breaker or trouble, all been done before in many ways…

Meanwhile, getting meaningful, useful and consistent data from an IMU for any purpose, especially a novel one, is fraught.

We all use products with IMUs in them, they do what they do. Smart phones. Quadcopter FPV racing depends on the flight controller and its IMU… so they can do amazing things.

But based on traffic on these fora, getting something new going can be a challenge.

So, start with the IMU and some simple code based on good examples and see if it can be used the way you hope.

a7

Ive got the nano on the way, will take heed to your advice and make sure I can work the main component before I head over to shark tank haha.

Thanks again for the help, Im off to the code forms now! Thanks for making the introduction to Arduino a pleasant one!