curriculum extension week

[large_ghostman]

hi i have a week off school so i can plan my school project, we get three of theese weeks in the year so we can plan and build a project for my tech class as i goto a tech school. i want to do something a bit different to what the others are doing, most are doing simple LED flash lights or night rider led displays that kind of thing.
this year i want a cool project. we get a budget from the school of £10 but we can add stuff found in the tech labs or what we have at home within reason. we can also blag stuff from companies. my idea this year is to make some dice but with a difference, i want to make small acrylic dice with leds in for the number and a acceleromter so when you throw the dice the numbers roll at a speed and rate depending on how hard you roll it (kind of like real dice) the number will be random generated by pic.

what do you guys think?

 

[Ian Rogers]

How will you display the number.... will it have 6 displays, one on each side?

 

[large_ghostman]

i was thinking a led matrix each side but now i think about it i would have a power problem :S i need to think about this as the description has to be handed in on monday from then on i am fixed to whatever i have chosen

 

[MrAl]

Hi there Little Chostman,


well, you could mount seven LEDs (or something like that, check actual die for LED arrangement) on one side of the cube and have them light up as if they are changing all the time similar to how a die might look from the top when rolled. That would still be cool because you would see the LEDs changing.
For the 'roll' though you'd have to come up with another method altogether. Perhaps a push button on the bottom so that when you drop the cube the button pushes in and starts the 'roll'. If you use a detector of some kind the higher it is dropped from the larger the response, which would change the speed that the LEDs change while the die is in 'motion'. Of you could just use a push button on top or side to start the sequence. Another possibility is to use the accelerometer to detect the drop. Still yet another possibility is to use a touch sensor to start the sequence.
Just some ideas, it would be nice to hear from others here too.

 

[Ian Rogers]

Imagine a ball with the stuff inside led's, battery, micro... weighted so the led's face up... in a clear cube floating so the ball always faces up!!

 

[jpanhalt]

I see nothing wrong with having the LED's on just one side of the cube. Which ones actually light would be dependent on the position of the accelerometer inside. Of course, you won't be able to see it, if the LED side is down. I don't see that as a problem for a school project, since you would know what the number should be for that position. A simple workaround would be to have the LED's on a pair of opposite sides.

Perhaps a tetrahedron might make an easier piece to work with.

Or, you could change the game a little...

Put the accelerometer in a ball (or any other shape, e.g. any Platonic solid). Transmit how it comes to rest to a stationary pad with the LEDs on it. That approach is a bit more complex because of the presumptive RF link, so it may be a bit much for just 3 weeks of work.

John

 

[cowboybob]

Sort of a "lesser" tech concept (although mechanically more difficult):

How about a gimbal made of concentric PVC20 rings, with a strong magnet in the center, situated such that it is weighted to one side, perpendicular to its mount "roll" ring axis. The whole assembly then positioned in the center of a cube that has six different LED arrangements for the faces of the die.

As the die flips and finally settles, the magnet (weighted such that it always ends up facing down and as close as possible to the die face) then triggers one of six unipolar hall effect sensors (available here) that are mounted in the center of each die face, which would switch on the LED matrix on the up-facing, opposite side of the die.

The hall effect would probably need to drive a simple transistor current switch for the LEDs.

This might have the added effect of the various die face LED matrices randomly flashing while the die rolls and the final die face LEDs flashing until the magnet settles.

 

[jpanhalt]

@Cowboybob, I like that idea. It might be much more doable in 3 weeks.

@Post#6
What I started to say before and deleted is that a cube will present some symmetry problems, because of the parallel planes. Accelerometers measure relative to the earth's surface. The symmetry problem can be solved, but adds a little more complexity. A tetrahedron will have fewer such problems.

John

 

[ghostman11]

logan hasnt seen theese posts yet, but just to clarify he actualy has untill june the something to complete it, the three weeks thing is he get a total of three weeks in the year to stay at home or goto a workshop ect and devote the time to his project. theese projects are mainly what his grades are based on ready for placement this september into his exam group, he then gets 3 years before his exams although it looks like he will study 3 years under the current system only to be in the first intake of the new exam they want to introduce!! seems totaly unfair to me to test him on an exam he wont have had any prep for! anyway i digress!

 

[jpanhalt]

That is understood, but many of us are veterans of development projects and a few weeks ballooning to several months is not unusual.

I suspect the goal is to get an "A" or equivalent. Even the simplest of what he is suggesting would be so much better than flashing LED's that the ultimate grade should not be an issue, so long as it works.

John

 

[large_ghostman]

`hello
i have spoken with my teacher and my last idea didnt seem like a good one, so i have decided to go with a alternative, as i have the anologue meters from my other thread i am going to do a clock/calendar with the readout displayed on the anologue meters once i crack the RTCC code for the micro the rest shouldnt be too bad! i am thinking of using pwm signals (software/interupt) to posistion the meters. so i will post questions details here as i get started

thanks again

 

[jpanhalt]

You could also set the analog meter up like an ohmmeter and use a digital potentiometer. Might give a steadier and more linear readout.

John

 

[large_ghostman]

i havnt tried them yet, i wont get a chance untill wed/thurs, i will try the digital pot way as well as pwm and a cap and see wich works best, i could also cheat a bit and use a shift register with resistor ladders or something like that it gives me a good chance to try different stuff out plus each thing i try and write about in the report gains marks so its worth trying several things just for the points . My nearest rival so far is doing a RGB LED torch but i dont think its going to work very well, not too sure yet as i havnt sneaked a look at the outline plan . the rest are doing simple stuff like a flashing led xmas tree. only other group doing more complex stuff are the year 12's (sixth formers) some of there stuff is realy good but dosnt affect my marks.

 

[jpanhalt]

Good luck. A lot of us are anxious to see it.

John

 

[KeepItSimpleStupid]

Put LEDS on all of the sides, but only light up the side facing up and only light them for a fixed amount of time after they stop rolling. If you pick up the dice, the last rolled number appears on the facing side.

If you have time:
Allow the other sides to light up randomly while they are rolling.
Use a light and charge them with a super capacitor.
And for a really fun project, derive the power by inductive coupling.

The power budget is the tough one. Instead of LED's use a 5x7 dot matrix display. I doubt you could pull an LCD display or an OLED deiplay because they would have to be custom designed.

I think inductive coupling would be really neat.

Don't mind me, I'm just in a creative babbling mood.

 

[Ian Rogers]

LG... Why don't you try little ( cheap ) 180° servo motors instead of analogue meters... Analogue meters can be expensive...

 

[ghostman11]

hi ian , Logan has the meters we got them cheap of ebay, i will get him to post a link to a post on here he did about them as i cant find it! i think there is 6 or 7 of them and they cost about £10 from memory for the lot. they look easy to take apart as well AND LOGAN NO you CANT raid my servo stash they are spoken for! lol