Low cost vibration / shake switches

[MalcolmZA]

Folks,

Many thanks for letting me join the forum.

I’m Malcolm, a retired automation engineer, living in South Africa.

I’ve been making basic motorcycle alarms for some time using a vibration / shake switch from a local importer. The importer changed their supplier and the switch they now supply has a sensitivity 10% of the original part and isn’t suitable.

The only other vibration switches I’ve found are an Assemtech VS-801P and VS-102 sold locally by RS Components.

RS doesn’t have local technical staff and the tech data on their site is too brief to decide if they’re suitable.

Is there a possibility someone on the group has experience with these devices and can offer some experience?

My main concern is they’re advertised as being suitable for alarms. But does this mean they’re intended to me stationary and alarm on the occasional movement and would mechanically wear out if mounted on a vehicle?

If anyone has other suggestions for detecting a motorcycle being nudged, I’d be very interested to hear .

Regards

MalcolmT

 

[rjenkinsgb]

We used one of the assemtech sensors a few years back for a design we did for a company making educational toys.
However, it seems they have totally re-designed them, the ones they sell now look very different.

The originals never gave any problem in a device intended to be thrown around by kids, but no idea on the new designs!

An alternative approach could be an accelerometer sensor as used in phones & drones etc.
Those are now extremely cheap and you can set any thresholds you want in your device, including shock/acceleration and tilt limits.

No moving parts and nothing to wear out.
They do need a microcontroller to continuously read data, but that can be a PIC or Arduino etc. that also costs next to nothing.

It would also give you the possibility of extra options such as for an alarm if the bike is dropped, even when the security alarm is not set - or any other abnormal movement, plus delays etc.

Examples:
**broken link removed**

Or with a compass as well:

GY-9250 9-Axis Accelerometer, Gyro & Magnetometer MPU-9250, UK Seller | eBay

Find many great new & used options and get the best deals for GY-9250 9-Axis Accelerometer, Gyro & Magnetometer MPU-9250, UK Seller at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

3-Axis Gyro + 3Axis Accelerometer + Tri-axial Magnetic Field IMU Module 9DOF | eBay

Find many great new & used options and get the best deals for 3-Axis Gyro + 3Axis Accelerometer + Tri-axial Magnetic Field IMU Module 9DOF at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Plus altimeter, even:
**broken link removed**

 

[MalcolmZA]

We used one of the assemtech sensors a few years back for a design we did for a company making educational toys.
However, it seems they have totally re-designed them, the ones they sell now look very different.

The originals never gave any problem in a device intended to be thrown around by kids, but no idea on the new designs!

An alternative approach could be an accelerometer sensor as used in phones & drones etc.
Those are now extremely cheap and you can set any thresholds you want in your device, including shock/acceleration and tilt limits.

No moving parts and nothing to wear out.
They do need a microcontroller to continuously read data, but that can be a PIC or Arduino etc. that also costs next to nothing.

It would also give you the possibility of extra options such as for an alarm if the bike is dropped, even when the security alarm is not set - or any other abnormal movement, plus delays etc.

Examples:
**broken link removed**

Or with a compass as well:

GY-9250 9-Axis Accelerometer, Gyro & Magnetometer MPU-9250, UK Seller | eBay

Find many great new & used options and get the best deals for GY-9250 9-Axis Accelerometer, Gyro & Magnetometer MPU-9250, UK Seller at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

3-Axis Gyro + 3Axis Accelerometer + Tri-axial Magnetic Field IMU Module 9DOF | eBay

Find many great new & used options and get the best deals for 3-Axis Gyro + 3Axis Accelerometer + Tri-axial Magnetic Field IMU Module 9DOF at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Plus altimeter, even:
**broken link removed**

Hi
Many thanks,

I'd not even considered accelerometer modules.
The current design uses an 8 pin PIC and should be able to accommodate the extra software.
Let me get googling

Regards
Malcolm

 

[rjenkinsgb]

OK, great! that should make it fairly straightforward.

If you are using one of the original 8 pin devices, have a look at the 12F1840; those are far faster with many more facilities, including hardware comms and I2C etc.

 

[MalcolmZA]

I've found a few local IOT and Arduino specialists selling ADXL335 breakout PCB's. That's good news so I'm not tied to a single supplier.
I've got a bunch of alarm PCB's partly assembled using the 12f675. The chip is socketed.
By pulling a couple of existing parts, the ADXL335 can be mounted in the existing enclosure and hooked up with a little wire.
And the micro reprogrammed.
Once the existing stock is used up I'll redesign the unit.

Interestingly , bare chips from Digikey are more expensive than an arduino daughter board

A couple of chips are ordered and should be here by weekend ( I live away from the main centers)
With a little overtime, V2.0 could be ready to go in a week.

Thanks again,
Much appreciated,

Malcolm