Low cost vibration / shake switched

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
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 .

BTW.. RS is the only international components company represented in SA, it limits my options.

Regards

MalcolmT
 

scorbin1

Joined Dec 24, 2019
96
I am not sure how complex your alarms control system is and I know this is not exactly what you asked for, but if it uses something like an arduino perhaps something like this would give you more than enough data to detect vibration and then some and also allow sensitivity adjustment as well. You could detect not only whether the motorcycle was bumped but if it was tilted upright, dropped, or really anything related to movement possibly even geo-fencing if you wanted. I have been contemplating building an alarm system for my motorcycles and this is the direction I have been leaning.

https://www.newark.com/stmicroelect...-Shopping-NewStructure-Gen-Semiconductors-ICs
 

scorbin1

Joined Dec 24, 2019
96
I looked at the specs again and I will have to take back the idea of geo-fencing with this chip. It does not have built in GPS, but some others like this do with a little higher price tag of course. Still I would consider this quite cheap considering the value it could add to a vehicle alarm system.
 

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
Good Morning,

Thanks for the input.
I'm trying to keep everything a simple and low cost as possible, the market is aimed at the small delivery bikes rather than the top end machines. The alarm uses a PIC12F675 uC, it might not have the memory to get the best out of the chip.

Yesterday I tracked down the European HQ of the manufacturer for the vib switches sold by RS. I sent an email which hopefully will reach some applications engineer.
,
I was reminded about the ADXL335 accelerometer available from many IOT and Arduino suppliers in SA.
Whilst it pushes the price, it's a piece of cake to interface to the uC ( just three A/I's). Plus its sold on a small PCB c/w 3v regulator.
I've got a bunch of half assembled PCB's, so pulling a few components, and i can patch the board in until the present batch is used. A couple have been ordered and hopefully I'll be able to start checking them out this weekend.

Cheers
MalcolmT
 

MisterBill2

Joined Jan 23, 2018
9,851
I am not familiar with the delivery bikes as mentioned, but a cheap trick that does work for motorcycles with a side stand is a small mercury switch, mounted far out of sight, that is open when the bike is leaning over parked using the side stand. Standing the bike up or tipping it over activates the switch and that starts a nasty sounding electronic siren in a hard to get to location. The alarm is powered thru a contact on the ignition switch that closes when the switch is in the off position, normally used for shorting the points in a magneto engine motorbike.
 

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
I am not familiar with the delivery bikes as mentioned, but a cheap trick that does work for motorcycles with a side stand is a small mercury switch, mounted far out of sight, that is open when the bike is leaning over parked using the side stand. Standing the bike up or tipping it over activates the switch and that starts a nasty sounding electronic siren in a hard to get to location. The alarm is powered thru a contact on the ignition switch that closes when the switch is in the off position, normally used for shorting the points in a magneto engine motorbike.
Hi Bill, Thanks for the input.
A delivery bike is 125-200cc motorbike, usually made in China.
The alarm also needs to protect when the bike's parked on the centre stand.
I'll be playing with a couple if accelerometers this weekend, I'm sure that's the best solution. It will be integrated in the electronics box, and allow the box to be mounted at any angle.
And not be affected if the bike is parked on the centre or side stand.

I'll do some tests with an arduino to prove the idea. Then convert to code to pic c .

Cheers
Malcolm
 

MisterBill2

Joined Jan 23, 2018
9,851
OK, so a true vibration sensor is needed. I have seen electronic ones with a simple piezo-electric sensor and mechanical ones with a pendulum on a spring and a close set contact. So probably the most sensitive will be the best choice.
An interesting consideration is the electrostatic presence detector system used with some alarm systems. But probably that is in a higher cost range, I am guessing.
 

DickCappels

Joined Aug 21, 2008
7,985
Somebody gave me a used automobile burglar alarm system. It included a vibration sensor that was basically a piezoelectric disk shaped transducer with a metal nut (the kind that goes on screws) stood above the transducer with a piece of stiff wire glued to one edge of the disk. That gave the nut leverage to make a larger signal. The disk was mounted on a spring to keep the signal going longer, I assume.

Just thought I would pass the idea along in case it is useful.
 

MisterBill2

Joined Jan 23, 2018
9,851
Somebody gave me a used automobile burglar alarm system. It included a vibration sensor that was basically a piezoelectric disk shaped transducer with a metal nut (the kind that goes on screws) stood above the transducer with a piece of stiff wire glued to one edge of the disk. That gave the nut leverage to make a larger signal. The disk was mounted on a spring to keep the signal going longer, I assume.

Just thought I would pass the idea along in case it is useful.
There is also a separate sensor for automotive alarm systems that is built much like that. But if the installer drops it the wrong way onto the garage floor the soldered on nut tears loose and it does not work. I was asked to fix it, and amazingly a small bit of glue and then a bit of solder and it did work again. Bottom line: Do not drop these sensors!
 

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
Somebody gave me a used automobile burglar alarm system. It included a vibration sensor that was basically a piezoelectric disk shaped transducer with a metal nut (the kind that goes on screws) stood above the transducer with a piece of stiff wire glued to one edge of the disk. That gave the nut leverage to make a larger signal. The disk was mounted on a spring to keep the signal going longer, I assume.

Just thought I would pass the idea along in case it is useful.
Hi Dick,

Thanks for the suggestion.
I've seen these sensors somewhere on the web. Some time ago I did fiddle with a dismantled piezo , spring wire and a nut.
It was hooked up to an analog i/p on an Arduino.
It worked surprisingly well but was (naturally) sensitive to its orientation.
They may not last too long on a dirt bike.

I've bought a few ADXL335's. The alarm will read all three axis's and trigger if any axis changes making the electronics able to be mounted in any orientation.

Cheers
Malcolm
 

MisterBill2

Joined Jan 23, 2018
9,851
An option not mentioned yet wouldbe to buy one of those sensors from RS and see if it has adequate sensitivity for your application. As I am not sure about what sort of tampering the system you sell is to protect against, it is a challenge to make a good suggestion.
 

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
An option not mentioned yet wouldbe to buy one of those sensors from RS and see if it has adequate sensitivity for your application. As I am not sure about what sort of tampering the system you sell is to protect against, it is a challenge to make a good suggestion.
Hi Bill,

I've just checked up on piezo sensors.
Most are more expensive than the ADXL335 breakout boards and larger.
One great thing about the ADXL335 is its available from a number of companies.

As soon as the current project is put to bed, I'll climb into the bike alarm and post the outcome.

Cheers
Malcolm
 

MisterBill2

Joined Jan 23, 2018
9,851
My next car electric project will be a system to light a 4-foot florescent tube leaning agaist the car when it is on dry pavement.I am not sure how much voltage that will require.
 

Thread Starter

MalcolmZA

Joined Feb 1, 2021
20
My next car electric project will be a system to light a 4-foot florescent tube leaning agaist the car when it is on dry pavement.I am not sure how much voltage that will require.
You could park under serious power lines and save a lot of work
Or have a word with your local spirit medium to get advice from Nikola Tesla.
 

MisterBill2

Joined Jan 23, 2018
9,851
You could park under serious power lines and save a lot of work
Or have a word with your local spirit medium to get advice from Nikola Tesla.
Neither of those would be effective for my application. Instead, recall the "Black Max" system that was sold about 25 years ago. My intent is to do better than that.
 
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