vibrating part run by battery and connects using bluetooth

Thread Starter

Shinehah

Joined Dec 29, 2023
17
How would I make a device that can be connected to using bluetooth that does nothing but vibrate on and off that is powered by battery. This needs to be able to fit in a person's hand. I would like to see how small this can be using a chargeable battery and how small it can be using a coin battery, or any other battery even smaller.
 

Thread Starter

Shinehah

Joined Dec 29, 2023
17
Each vibrating piece of the device would be held in each hand and would vibrate alternately. They would connect to an iPhone via Bluetooth. An app controls them. Ideally the app would be able to change the settings and control the vibrating parts and change the duration of the vibration, how long the pause would be between each vibration, and the intensity of the vibration.

I would an EMDR device. It draws the attention of the person holding them in his hands to the vibrating piece that is in his hand, so that his attention is directed side-to-side repeatedly. It’s used by mental health therapists to treat trauma that persist after the occurrence of the traumatic event.

I would need each vibrating peace to be encased so they would comfortably be held in the patient’s hand. I need help at first with selecting the microcontroller, if it requires one, as I presume. Each piece would be able to have its batteries charged and last a practical length of time so that the person using it would not have to constantly recharge or replace the batteries. Each piece would have a size to be able to be held comfortably without being too large to be comfortable to hold. I have found the vibrating piece I want to use listed at Jameco as “Vibrating Motor 3 Volt DC 60mA 6500rpm 0.18" Shaft Diameter”, here: https://www.jameco.com/z/7ZK692-R-Jameco-ReliaPro-Vibrating-Motor-3-Volt-DC-60mA_256365.html.

What microcontroller would allow me to do all that and be able to be encased so that the piece in each hand would be the optimal size? Would I need to exclude any features I want in order to allow for optimal size, like perhaps the ability to change the vibration to the different settings that I wrote above?
 

Reloadron

Joined Jan 15, 2015
7,513
No mention of the vibration force? Vibration of a cell phone or vibration of an earthquake? You can buy small cell phone vibration motors very inexpensive if that is enough. There are about a dozen chips out there used for Bluetooth for example an ESP8266 module. You really need to better define your project and the goals. A simple Google of vibrating motors will bring up a dozen hits or more and the same is true for ESP8266 modules.

Ron
 

Thread Starter

Shinehah

Joined Dec 29, 2023
17
Here's a picture of the vibrating component at the link I gave in my last comment. What I need help at the first is with selecting a microcontroller that I'm positive will do all that I want to as I described in my last comment.

It looks like the image I dropped in this comment isn't showing. Here's a link to the picture I share using a link in my iCloud Drive: Vibrating Motor 3 Volt DC 60mA 6500rpm 0.18" Shaft at Jameco.com
 
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Thread Starter

Shinehah

Joined Dec 29, 2023
17
I've looked at different microcontrollers and some tutorials that connect a vibrating motor to a microcontroller, but it didn't include connecting a Bluetooth component.
 

Reloadron

Joined Jan 15, 2015
7,513
OK you have a few considerations. The motor you linked to runs on 3.0 VDC and my guess is 3.3 VDC will do just fine. All small vibrating motors like this will have wires. I have never seen a wireless motor. The motor current is 60 mA (0.060 Amp) and I know of no uC (micro-controller) capable of 60 mA on a DIO pin. That means your motors will need to use a driver transistor so your uC will drive the transistor and the transistor will drive the motor.

I suggested using an ESP8266 which can be controlled from a phone. So the ESP8266 or similar uses two DIO (Digital In Out) pins set up as Out driving two redundant transistor configured like this...
2N2222 Motor Drive.png

There are even apps for the ESP8266 to phones. This is not complicated. I assume you have a WiFi network to connect to?

I can get a 5 pack of about the same motor but encapsulated and water proof for about $10 USD. They can be found here.

Ron
 
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Audioguru again

Joined Oct 21, 2019
6,688
The motor draws too much current (60mA) for one coin cell battery. The maximum continuous current for a CR2032 battery is 3mA but 50mA for one second pulses will work. The battery voltage soon runs down to the minimum motor voltage of 2.4V and the patient will hear and feel the motor slowing down.

Two AAA alkaline batteries in series produce 3V and will drive the motor for about 7 hours when the minimum motor voltage is reached.

The simple brushed motor might not last long since it wears out soon in cheap toys. Replace the motor each time you replace the AAA battery cells.
 

Thread Starter

Shinehah

Joined Dec 29, 2023
17
I suggested using an ESP8266 which can be controlled from a phone. So the ESP8266 or similar uses two DIO (Digital In Out) pins set up as Out driving two redundant transistor configured like this...
I found some from Temu when I did a search. Are they a reliable source to purchase something like this ESP8266? And I do have Wifi. I would think I could use a hot spot on a smartphone as the Wifi. I use an iPhone.
 

Ya’akov

Joined Jan 27, 2019
9,117
Welcome to AAC.

To do this “properly”, that is in the way that it might be produced commercially, you should use BLE and a purpose built RF (SoC), for example like the FSC-BT981 from Feasycom. This module is only about 12 x 15 x 2mm, and consumes ~5mA. It has several PIO (Programmable Input Output) pins which you would use for motor control.

1704025217792.png
FSC-BT981

It comes with default firmware that wouldn’t work for you but custom firmware can be written. Your new firmware would provide some very simple BLE services that would allow an (authenticated) app to command one or the other units to run for n seconds. The app would coordinate the alternation—or you could have the devices talk to each other to do that.

The firmware can be produced with the help of the manufacturer. The application for iOS, will require you to enroll in Apple’s Developer program ($99.00/yr) so you can sign and distribute iOS apps. You will probably have to learn Swift, Apple’s preferred language for development.

Next is the motor. Haptic motors can be much smaller than the one you’ve imprinted on. These, for example, are much smaller and very cheap. They are 10mm x 3mm, and cost about 40 cents USD in quantities of 10.

1704025967348.jpeg

Concerning a power supply, the most sensible thing is to plan on a single LiPo cell. This means you are going to have to include some charging ability (not a big deal) and design for 3V3 to accomodate the cell’s 3.7V nominal voltage.

Just how much capacity the cell should have is a matter of calculation so you can’t yet decide. You have to account for the current requirements your desired runtime, and how much space you are willing to use in order to choose a cell. For an example, though, pulling a number from… experience… a 220mAh cell in a long, thin aspect ratio might be an option.

1704026600439.png

a 501240 LiPo cell, which translates to roughly 5mm thick (50), 12mm on the short side (12) and 40mm on the long (40)

This is a much more complicated project than you might have guessed. It involves a lot of different specialties and a great deal of practical knowledge. I don’t know how much time and money you are prepared to invest in this, but don’t underestimate what will be needed.

Now you could do this as a one-off hobby style project using somewhat simpler things. Were I trying to do that, I might, in fact, use the ESP8266 but I also might choose something like the Seeed Studio Xaio, or something from Nordic Semiconductor.

I would probably skip Bluetooth and use lightweight web servers running on the devices themselves in order to avoid an app. I might also choose to make them asymmetrical, that is, have one be the controller and the other a peripheral to it. In that case, I might use Wi-Fi and HTTP for controller ←→ smartphone communications, depending only on the phones browser and eschewing an app. Then I would use something else for controller ←→ peripheral communication, like Zigbee for the radio link and a simple command set for control.

I might also consider having only the motor be handheld and the rest being worn on the wrist with a simple “slap bracelet” arrangment or something similar, or maybe just let the wrist contact suffice and make the motor internal. Making something comfortable to grip, in size and shape, is likely to be a real challenge.

1704027777789.png
the metal band inside this silicone sleeve stays flat until it is deformed so that it returns to its coil shape—easy on and off

The motor and power supply comments above still apply.

Please don’t imagine I am trying to discourage you. I am trying to give you an idea of the practical difficulties. You should expect to make several prototypes as you go along, and to spend at least 10 times what the finished device would cost alone—if you take the hobby route—and much more if you intend to make this a marketable product (and for many things I haven’t mentioned that you will discover along the way).
 
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