Absolute beginner, would this be possible?

So before I start learning, I was wondering if it would be possible to create a very small device (the size of a small coin) that is simply made of a battery, Bluetooth chip and accelerometer. The device can be used in conjunction with a computer (wirelessly) to have a constant reading from the accelerometer.

If so, it would be much appreciated if you could outline the basic steps I would have to take to begin learning how to create something like this.

Thanks!

This reminds me of a Phillips seminar I went to a long time ago.
They told us that they had invented the CD player.
It was the size of a wheelbarrow.
They said that it worked.
The only think they still had to do is to make it smaller.
Maybe you could do the same.
Leo..

This can be done if you have your own engineering laboratory with access to smd production equipment.

You don’t? Then forget it.

Weedpharma

Absolute beginner, would this be possible?

Probably not within your capability for a long time.

How big are the coins in your country? The answer is different if you are in Australia (big coins) or the USA (small coins.)

The accelerometer is tiny - The ADXL345 is 3mm x 5mm x 1.42mm (I just happen to have a vernier and an ADLX345 in my lap.) The Arduino chip to control it is 7mm square or possibly smaller. The bluetooth module is likely bigger. The latest Bluetoon BLE modules are pretty small though.

You are going to have to design your own PCB. If you want really small then you need to find a service that will print thin PCBs. The standard PCBs from OSHPark are pretty thick. A week learning Eagle should be enough for you to get a design out to a fabrication shop.

I'm sure I could get it down to the footprint of an Australian 20c coin, or maybe an American quarter. It would be a lot taller though. It really depends on your battery life requirement. The overall size will be driven by the battery.

The problems I am envisioning with this project are the battery and the matter of needing to stack things. You’re going to need a micro controller obviously, so when you say “Coin sized” I automatically assume you would like the project to be decidedly round. There are some Arduino boards that happen to be round and these are typically used in wearable projects. There’s the Gemma and the Lilypad, there’s also a snappable battery board for the lilypad so you might be able to take those two and solder them together. As for the accelerometer and bluetooth, You’re going to have to get creative with adding these parts. You can get both in relatively small packages though so it should be possible. It might be possible, as long as you make sure all of the components are insulated from each other to sandwich the accelerometer and bluetooth module in between the Lilypad and the battery module and attach the two outer boards together with header pins.

That’s what I come up with off the top of my head as far as something sorta coin sized and decidedly round. It might be more like cookie sized when it’s all finished though.

–Edit: The Lilypad simple snap is actually the full lilypad board with a battery on it. The terminals have been replaced with snaps for ease of use in wearable projects. So you only need the one board.

Something like this?

These Deltino devices may give you some ideas. They include an Atmega328, a Cypress 2.4GHz transceiver and a h-bridge in a very small package. They measure about 12x22mm - the exact details are on the website. I use them for radio control of N-Gauge model trains.

I suspect the biggest obstacle to your size specification will be the battery.

...R

Robin2:
These Deltino devices may give you some ideas. They include an Atmega328, a Cypress 2.4GHz transceiver and a h-bridge in a very small package. They measure about 12x22mm - the exact details are on the website. I use them for radio control of N-Gauge model trains.

I suspect the biggest obstacle to your size specification will be the battery.

...R

The size will not be a problem since I have seen several samples from one Japan IC company with ble and acceellerate integrated. (size: 2mmx2mm)
These chips could be easily used even for Intelligent Jewerly like ring.

I agree with you that battery will be the most difficult part.

Eg coin battery 1302 would have 210mah
supposing you are using the BLE with 80Hz interval (80Hz will be the normal rate for 6-axis accellerate meaturement)

current for ble to do one sending or receiving. peak current will be 19ma
for 6-axis accellerate meaturement. peak current will be 5ma

Then the worst case means you ONLY get 210/(19+5) = 8.75 h

I am not sure whether this meets your expection