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wireless powerlifting scoreboard

Posted: Thu Oct 09, 2014 6:25 am
by RohanHawthorne
I want to build a wireless powerlifting scoreboard for a local club.

When a powerlifter does his feat of strength, he is judged by three judges: one main, and two secondaries. The scores are sent to a reciever from three, two button transmitters, and when all three scores are in, they are sent to the lights (red for fail, white for pass). Then the head judge can reset the lights.

Basically, the Pi needs to connect to three sets of lights (both red and white), and be controlled by transmitters (at the moment I'm thinking mobiles) which tell the lights to turn on and off. I can code, but I'm still new to Rasberry Pi (I haven't even bought one yet) and want to know if this whole thing is possible. Just brainstorming, I think this would be possible by creating a website on the Pi, a wireless network from the Pi, and connecting to the website via the phones.

I've listed from hard to easy my proposal:

1. Interface from Pi to lights - I need help with this
2. Program to control lights and recieve input from iPhones - I can do
3. Wireless network from Pi which the phones connect to - I think this has already been done

Does anyone have any ideas regarding this ?

Thanks,

Rohan.

Re: wireless powerlifting scoreboard

Posted: Thu Oct 09, 2014 7:59 am
by BMS Doug
Select the lights you will be using on the scoreboard. note the power requirements (voltage and current).
Select a switching device that can be triggered by the pi GPIO that is capable of switching your selected lights.

There are two types of switching device: Relays or Transistors.

Relays are capable of switching a broad range of devices, within fixed limits of voltage and current for each relay. you can cascade relays so that a smaller relay will power a larger relay which powers the load. (a commercial relay board for the pi will have a transistor triggering the relay). beware of back EMF when the relay is de-energised (a commercial relay board will have a shorting diode fitted to remove the back EMF).

Transistors and MOFSETs are very capable of switching loads but will have specific limitations as to what they can switch. A properly selected MOFSET is superior to a relay but an incorrectly selected MOFSET won't work at all. (AC load requires an AC MOFSET, a DC MOFSET won't work. DC load requires a DC MOFSET and an AC MOFSET won't work).

Re: wireless powerlifting scoreboard

Posted: Thu Oct 09, 2014 8:41 am
by RohanHawthorne
Doug that's a fantastic reply, thanks very much for that. Can you post some links to example products / solutions ?

I was also looking at a usb controlled powerboard - maybe that can be controlled by the pi ?

Rohan

Re: wireless powerlifting scoreboard

Posted: Thu Oct 09, 2014 8:56 am
by RohanHawthorne
Or maybe this: http://www.ebay.com/itm/USB-Eight-8-Rel ... 0919616362

I'm just starting on this project, so I'm still scoping possible solutions.

Re: wireless powerlifting scoreboard

Posted: Fri Oct 10, 2014 1:52 am
by RohanHawthorne
Hmmn. looks possible:

https://www.youtube.com/watch?v=C_-3KzS ... aJhsGZzwDg

Just have to work out now how they did it!!

hahahaha

Rohan.

Re: wireless powerlifting scoreboard

Posted: Fri Oct 10, 2014 9:31 am
by BMS Doug
I'd recommend using a GPIO switched relay module instead of the UPS module.

google: raspberry pi relay module
and pick one that looks good to you. I would recommend picking one with opto-isolated inputs. (like this one perhaps)
Some concerns with the relay boards: some of the boards may have a higher consumption from the GPIO than the pi is rated for, if all relays are activated at once. this concern is not as bad in your use case where you will only be activating a maximum of three lights at any given time.

If desired you could add a MCP2308 or MCP23017 I2C port expander to provide GPIOs to drive the relay board.

Re: wireless powerlifting scoreboard

Posted: Fri Oct 10, 2014 10:36 am
by BMS Doug
RohanHawthorne wrote: I think this would be possible by creating a website on the Pi, a wireless network from the Pi, and connecting to the website via the phones.
This part is very easy, just install Apache and PHP controls and write a series of HTML pages (a home page + one page per judge would probably be best). You can use wiringPi to have PHP commands from the webpage to directly control the GPIO.

Install wiringPi, Apache, PHP

$ sudo apt-get update
$ sudo apt-get upgrade
$ git clone git://git.drogon.net/wiringPi
$ sudo apt-get install apache2
$ sudo apt-get install php5


I followed this instructable for making my webserver.

Re: wireless powerlifting scoreboard

Posted: Tue Aug 18, 2015 6:03 am
by RohanHawthorne
I built it!!!

It's awesome!!!

Thanks for all your help Doug.

I ended up using hostapd and a lamp setup. If anyone is interested in this system, please let me know.

Cheers,

Rohan.

Re: wireless powerlifting scoreboard

Posted: Wed Aug 19, 2015 10:01 pm
by BMS Doug
I'm glad to hear that you got this working.

It's nice to hear how people's projects turn out.

Re: wireless powerlifting scoreboard

Posted: Wed Oct 14, 2015 10:01 pm
by mor2rd
RohanHawthorne wrote:I built it!!!

It's awesome!!!

Thanks for all your help Doug.

I ended up using hostapd and a lamp setup. If anyone is interested in this system, please let me know.

Cheers,

Rohan.
I'm very interested in this. Can you send a pic?

Re: wireless powerlifting scoreboard

Posted: Sun Feb 28, 2016 11:34 pm
by Hyuukai
Very interested in this project but looks like nobody is around :(

Re: wireless powerlifting scoreboard

Posted: Sun Feb 28, 2016 11:35 pm
by RohanHawthorne
Sorry sorry - I just found the replies. I will send a pic as soon as I get home, maybe even a youtube video.

Rohan.

Re: wireless powerlifting scoreboard

Posted: Thu Mar 31, 2016 9:51 pm
by tomco
Hi all,

I would like to do the same project but a littlebit different.
I would that the results are shown graphical. (I will connect raspberry to a TV)

I have 7 switches, 3 for good lift, 3 for fail and 1 for reset. They are connected to a GPIO.
Now I have a problem how this show on a display - graphicaly.
Which program should I use?


Thank for help.

Re: wireless powerlifting scoreboard

Posted: Tue Oct 25, 2016 12:54 pm
by JonnyG_1980
I want to do this as well, but without the need for a set of lights.

I'd like to have the referee' decision sent to a screen, and have them control the white or red light with a demolished wireless mouse (1 for each referee).

Any advice would be greatly appreciated.

I think I need to create a website on the Pi, some code that lights up the decision (only after all three inputs are triggered) and then can be reset to clear by another input (possibly the scroll wheel on the mouse).

Re: wireless powerlifting scoreboard

Posted: Tue Oct 25, 2016 2:27 pm
by aBUGSworstnightmare
Use ESP8266 based modules instead of your mouse, add to buttons to them and let them 'talk' to your host i.e. via http requests.
Don't know if this would be cheaper but will give more flexibility for sure

Re: wireless powerlifting scoreboard

Posted: Tue Oct 25, 2016 2:46 pm
by JonnyG_1980
aBUGSworstnightmare wrote:Use ESP8266 based modules instead of your mouse, add to buttons to them and let them 'talk' to your host i.e. via http requests.
Don't know if this would be cheaper but will give more flexibility for sure
I'm even considering just having the referees use their phones and connect them wirelessly to the pi, which in turn will display the decision, but the more I look at it the more complex it becomes.

Re: wireless powerlifting scoreboard

Posted: Mon Sep 16, 2019 8:44 am
by Qwerty1992
JonnyG1980 did you achieve this?

I’m wanting to setup something similar for my local club.

Re: wireless powerlifting scoreboard

Posted: Mon Sep 16, 2019 10:45 am
by B.Goode
Qwerty1992 wrote:
Mon Sep 16, 2019 8:44 am
JonnyG1980 did you achieve this?

I’m wanting to setup something similar for my local club.


'Jonny' hasn't been back for the last 3 years, since resurrecting a thread originally started - and resolved - in 2014. I think it is unlikely you will get a reply - but not impossible...