EV Car brake pressure sensor

[ireson75]

Hi all,

I am looking to measure brake pedal position for our Brake System encoder for our EV Formula Student car.

Integrating a rotary potentiometer within our pedal box design looks to be tricky so we are thinking of using a pressure sensor.

Looking into this, most seem to be incredibly expensive (£100+!), does anybody have any more cost effective solutions?

Many thanks,

Tom

[Claude Rouelle]

Not worth to introduce yourself?

[JulianH]

Maybe linear potentiometers could be a more cost effective solution?

Quick tip:
Don't look for the posted prices online. Call the companies and ask if they want to help some bright students to achieve something great.
Usually that gives you the parts for a fraction of the posted price.

(To be fair, then you have to tell them, who you are and which university you are representing which will make Claude really happy )

[Claude Rouelle]

Tom,

Ideally you would need pedal stroke AND both front and rear brake pressure sensor. The price you mention is a normal price. If you want to play in the playground of the big guys you have to stop wearing shorts. What I mean is there is a minimum budget that you need to evaluate to decently compete in Formula Studen. Some basic reality checks on budget need to be performed. Nothing prevent you to get the sensors free of charge like many teams do though a collaboration with the industry.

There are some rotary potentiometers that can be bought at Tandy/ Radio Shack for 15 US$ I remember an Australian team using simple radio volume potentiometers on their rockers to measure suspension movement and exploit the damper velocity histogram method. Cheap, not super precise but useful. Just be careful of the resolution: do not measure an angle of 36 degrees of the throttle pedal movement and 0.5 volt with a 360 degrees, 0 to 5 volts sensor. That would be less than 10 % resolution.

[Adam Farabaugh]

If 100 euro is too much for a sensor, how are you building an electric car? That's less than 1% of the cost of the car surely.

http://www.digikey.com/product-searc...=0&pageSize=25

[ireson75]

Hi all,

Thanks for the speedy replies! Apologies for the lack of introduction - a bit about me and my team for you Claude and anyone else interested;

I'm from University of Leicester Racing in the UK 2016 will be our 2nd year of competing at Formula Student UK. Sadly, we did not pass EV scrutineering at Silverstone this summer however this was not really suprising - our team was badly organised and ill-prepared generally. However, we learnt a lot (which is the most important thing in my eyes!) and are far better prepared already for 2016.

You can check out our social media www.uolracing.co.uk, www.facebook.com/uolracing and www.twitter.com/leicesterracing

Maybe linear potentiometers could be a more cost effective solution?

Quick tip:
Don't look for the posted prices online. Call the companies and ask if they want to help some bright students to achieve something great.
Usually that gives you the parts for a fraction of the posted price.

(To be fair, then you have to tell them, who you are and which university you are representing which will make Claude really happy )

Okay, will have an investigate - I didn't think about linear potentiometers and thats a great idea. Thanks for your help.

Tom,

Ideally you would need pedal stroke AND both front and rear brake pressure sensor. The price you mention is a normal price. If you want to play in the playground of the big guys you have to stop wearing shorts. What I mean is there is a minimum budget that you need to evaluate to decently compete in Formula Studen. Some basic reality checks on budget need to be performed. Nothing prevent you to get the sensors free of charge like many teams do though a collaboration with the industry.

There are some rotary potentiometers that can be bought at Tandy/ Radio Shack for 15 US$ I remember an Australian team using simple radio volume potentiometers on their rockers to measure suspension movement and exploit the damper velocity histogram method. Cheap, not super precise but useful. Just be careful of the resolution: do not measure an angle of 36 degrees of the throttle pedal movement and 0.5 volt with a 360 degrees, 0 to 5 volts sensor. That would be less than 10 % resolution.

Again thanks for your help.

I understand the cost of the sensor is normal, it just seems a hell of a lot for something which is really pretty simple! Motorsport prices eh!!

I was hoping a sensor from a major OEM might be suitable that could be purchased for a fraction of the cost? I understand reality checks are required though and of course if we do need to spend the money we will.

If 100 euro is too much for a sensor, how are you building an electric car? That's less than 1% of the cost of the car surely.

http://www.digikey.com/product-searc...=0&pageSize=25

I never said it was too much, I just said it was a lot for 1 sensor and asked if anybody had any more cost effective solutions!

Cheers, Tom

[ggscott]

While it is a bit late there is 1600PSI pressure sensors available on Ebay for around $30US. No guarantee of quality but they look very similar to the Honeywell equivalents.