Xalloumi
Posts: 9
Joined: Tue Jun 19, 2018 3:44 pm

[Help] Trigger mechanism

Thu Jul 19, 2018 10:53 pm

Hey guys!

I am thinking to connect an accelerometer sensor on my RPi Zero W, which after an acceleration will trigger some springs. I am trying to figure out how can I create the mechanism that triggers the springs. My first thoughts are how guns mechanism works but my imagination can't go any further! :)

Any tips/ thoughts/ experiences?

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The Traveler
Posts: 361
Joined: Sat Oct 21, 2017 3:48 pm

Re: [Help] Trigger mechanism

Thu Jul 19, 2018 10:59 pm

will trigger some springs.
A bit vague. Like hitting them with a hammer? Or launching large ball bearings at them? Or placing them in a compressed state beneath a seat cushion and having someone sit on them?

"Triggering" could be done in a myriad of ways ... ?
Last edited by The Traveler on Fri Jul 20, 2018 2:02 am, edited 1 time in total.
Retired IT professional, C programmer and "beardie weirdie".
RPi interests: Developing an Infinite Improbability Drive
“Thinking outside of the box allows you to get rewards outside of your reach.” Matshona Dhliwayo

PhatFil
Posts: 264
Joined: Thu Apr 13, 2017 3:55 pm

Re: [Help] Trigger mechanism

Thu Jul 19, 2018 11:11 pm

motors, stepper motors, linear actuators and solanoids are just a few of the devices you could employ to create motion on demand depending on the specifics its tricky to suggest which might be most optimal.

when looking to employ anything that draws more than a nominal current you will also want to consider if its compatible and within the capacity of the pi to power and if not employ a 2ndary power source.

Xalloumi
Posts: 9
Joined: Tue Jun 19, 2018 3:44 pm

Re: [Help] Trigger mechanism

Fri Jul 20, 2018 1:44 pm

PhatFil wrote:
Thu Jul 19, 2018 11:11 pm
motors, stepper motors, linear actuators and solanoids are just a few of the devices you could employ to create motion on demand depending on the specifics its tricky to suggest which might be most optimal.

when looking to employ anything that draws more than a nominal current you will also want to consider if its compatible and within the capacity of the pi to power and if not employ a 2ndary power source.
Linear actuators is more like what i am looking for but i need it to be strung out with decent power and be able to push it back to it's position

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The Traveler
Posts: 361
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Re: [Help] Trigger mechanism

Fri Jul 20, 2018 1:57 pm

Linear actuators is more like what i am looking for but i need it to be strung out with decent power and be able to push it back to it's position
Better, but still vague. If you want to compress a spring, then you need to know how much force the linear actuator requires and how long stroke to compress the spring That, in turn, will dictate how much electrical energy is needed and how to control it. So, it would be helpful to know more about the spring characteristics to calculate the mechanical and electrical requirements for the actuator.
Retired IT professional, C programmer and "beardie weirdie".
RPi interests: Developing an Infinite Improbability Drive
“Thinking outside of the box allows you to get rewards outside of your reach.” Matshona Dhliwayo

PhatFil
Posts: 264
Joined: Thu Apr 13, 2017 3:55 pm

Re: [Help] Trigger mechanism

Fri Jul 20, 2018 7:14 pm

Altitude triggered mechanism?? model rocket recovery parachute ejection mechanism 'springs' to mind as a source of inspiration.

Or it could be interpreted as a need to control a bistable mechanism??

at some point the mystery looses its appeal.. wtf are you upto ;) ??

Xalloumi
Posts: 9
Joined: Tue Jun 19, 2018 3:44 pm

Re: [Help] Trigger mechanism

Fri Jul 20, 2018 9:25 pm

Thank you for your replies again!

Well, I am interested to make a device case which will be used as an "airbag". I was inspired by this guy: https://www.reddit.com/r/interestingasf ... rbag_that/

But I am not going to make exactly the same thing. First of all, I will use a raspberry pi :lol: . Also instead of using "hooks" like this guy did, I am thinking to use solenoids (https://shop.pimoroni.com/products/mini-solenoid) which will push the springs. The springs will have plastic/silicone cups in order to protect the device. Lastly, I will use an accelerometer sensor to help the solenoids to be triggered.

This is what I have in mind overall, and also this is the first time I will use a RPi, that's the reason my descriptions are a bit vague :roll:

Btw so far i manage to install Rasbpian on my RPi zero W :lol:

PhatFil
Posts: 264
Joined: Thu Apr 13, 2017 3:55 pm

Re: [Help] Trigger mechanism

Tue Jul 24, 2018 11:14 pm

https://www.ebay.co.uk/itm/OMRON-ELECTR ... m570.l1313

might be useful.. you would also need a stepper motor driver or circuitry too.. and consider adding a smal lipo battery to provide motor power.

good fortune with the project, keep us up to date too ;)

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