Looking for help! – University Major Project.

[AdamMortlock]

Hi guys,

Warning! I am no Electrical wiz!

I am a (BA) Product Design student studying at the University of Derby. I am currently going through my major project research module, I have evaluated the market and found a need for an automatic light switching device between two different LED’s (mimicking a car full beam/ dipped beam light setup) I want this product to automatically do this through the sensing of its surroundings.

I have done research into Photodiodes, Accelerometers and Reverse-Biased LED’s, I want to be able to make this product change through either the monitoring of the light using a reversed biased LED (to know when a car’s lights are coming towards it, or going into street lit areas) or the use of an Accelerometer to monitor movement in the surrounding area for objects moving faster or slower than the cyclist, but not stood still. I will be running this product from a set of rechargeable batteries (early on in the project so not sure specifically on types Li-on most likely, something giving around 2300mAH)

As I say I really have little experience in this (If any), I hope someone could give me help/ advice in what is realistic in a solution for this project, I understand I have not given much to go off. Obviously the smaller and lighter the solution the better.

I will check back on here very regularly (every couple of hours) and look forward to see what you all know! Please if I am going completely up the wrong street with the technology I have already looked into or this is an unrealistic project please tell me!

For a bit of inspiration: https://www.kickstarter.com/projects/1670187625/seesense-the-intelligent-bike-light-with-road-sens this is a light that is a more complex version of what I am trying to do (I think)

Thanks for your time,

Adam.

 

[Misterbenn]

the use of an Accelerometer to monitor movement in the surrounding area for objects moving faster or slower than the cyclist, but not stood still.

An Accelerometer would only measure the vibration/acceleration of the cyclist not the surrounding objects.

A photodiode can easily be set up to detect other car headlights / daylight.

 

[AdamMortlock]

Ahh, my bad, thanks for letting me know

 

[JimB]

My first thoughts are that the project divides fairly neatly into two parts:

1 A switching and LED driving circuit.

2 Various sensing circuits.

You will need to define the interface between the sensing and the switching circuits so that you can try different sensing circuits without having to redesign the LED switcher. Also, so that several sensors can connect to the switching circuit at the same time.

To start the ball rolling, I offer the circuit in the attachment as a simple LED switching circuit.
When the input contacts are open circuit, LED 1 will be illuminated and LED 2 will be dark, and when the input contacts are short circuited LED 2 will be illuminated and LED 1 will be dark.
The input could be switched by either a simple contact (switch or relay) or an open collector transistor.

The sensing circuits will be more difficult, as previously stated, an accelerometer will not do what you want.

JimB

 

[Misterbenn]

Presumably your 'product' would be retro fitted into cars? in which case have you looked at how they currently switch between full /dipped beam?

Also would the user want to be able to override this function, just in case it goes crazy and starts putting full beam on all the time!

 

[AdamMortlock]

Well this is for biycle's... and yes an override would be essential incase such a thing happened.

 

[ronsimpson]

1 A switching and LED driving circuit.
View attachment 82174

Your circuit has LED1 on/LED2 on but does not have a mode for no LEDs on. Also no "all LEDs on".

 

[JimB]

ronsimpson said:

Your circuit has LED1 on/LED2 on but does not have a mode for no LEDs on. Also no "all LEDs on".

That is quite correct, I was responding to the original "specification" which stated

a need for an automatic light switching device between two different LED’s (mimicking a car full beam/ dipped beam light setup)

I was merely offering a simple start to the design process.

Without a wider understanding of what the sensors part of the project will provide, I can only suggest that the case of both LEDs off is provided by the power switch.

JimB