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RS Components - Tweet Race

9530 Views 135 Replies 16 Participants Last post by  Doug

Enter your design for the world's first slot car race powered only by Twitter

We're looking for SlotForum members who think they'll be up for the challenge of designing a slotcar control system, that will use the power of Twitter, to race two cars on a Scalextric track.

There is an API available that must be used, but you must come up with the physical interface design.

There's a £150 RS Components spending spree up for grabs if your design is chosen.

The closing date for entries is 31st July and the launch of the public voting will be second week of August

On your marks...

Please email [email protected] for more details.



How it will work:

Once the system is built and the track is ready, a Facebook page will be launched accompanying the Twitter campaign.

The Facebook page will let people register with their Twitter handle and state which car they will be voting for (either Red or Blue for example).

Then each time a user Tweets the correct hashtag (either #RSRed or #RSBlue) the car will move automatically.

For one week the amount of tweets for each car will be recorded, and then on the final day of the campaign a live stream will run showing the cars moving depending on the amount of Tweets each has received in that week. And then for the remainder of the day people can continue to Tweet using the correct hashtags and the cars will move in real time.

Get involved for a bit of fun. Perhaps the slowest slot race of all time, but perhaps the race with the most amount of participants !
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Sounds like RS had to find something for a work experience person to do and they came up with this project. Why on earth don't they do something more creative with a strategy element rather than a moronic small movement per tweet if I understand correctly. Glad to see the Erik has popped in to add some poetry to this disorganised competition.
I would add that hardly any of my students (18 to 22 years old) use Twitter apart from the odd one who uses it for job searches. So who is a typical user - must be more than just geeks but I haven't found one yet

Anyway I have my bot network ready to send a million tweets in the first second of the competition, so put your money on the blue car (only joking)

In fact, it reminds me of the minature horses in 60s amusement arcades on the pier where the competitors had to get balls into a hole, marked run or trot, to move their horse forward a notch ... or something like that
Edit, not very clear but this is the best pic I could find:


PS Whilst I'm here, maybe RS might deign to divert some of their work experience people to deliver my Raspberry Pi for which they relieved me of my pennies 7 weeks ago

(yes I know the order said despatch might take 9 weeks but why take my money if you knew that?)
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QUOTE (Sam RS @ 13 Aug 2012, 12:55) <{POST_SNAPBACK}>Thanks Erik!Que?

QUOTE (Sam RS @ 8 Aug 2012, 10:35) <{POST_SNAPBACK}>As a lowly work experience boy (
), I'm not sure if there's anything I can do.
Where would we be without the British sense of humour ...

Anyway, good luck with the competition.
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Click on track to download Racer track plan (.scc). Feel free to modify/improve.

46*Radius 4 curves (C8235). 6*Half Straights (C8207); 4*Quarter straights (C8200); 35*Straights (C8205)
4.18m*4.17m. Track1 = 24.82m; Track 2= 24.33m

(NB these figures have not been checked & may be wrong.)
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Hi Sam,

The above was done in Ultimate Racer 3.0:

If you are actually going to buy one though I think Track Power is easier to use and prettier
Nb they are not compatible with each other. Both have limited demo versions.

Scalextric own track designer is free but has bugs and I have never managed to complete a track plan:
However, there's a new Scalextric iPhone app which I haven't tried:

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17.42m/17.91m if UR3 is correct.
To get down to 50' you will probably need to use some Radius 3 and maybe Radius 2.
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Another few feet shaved off:

Some Rad 3 curves substituted for Rad 4s. I've tried to at least keep the piece at the entry to curves as a Rad 4 to reduce deslots, assuming you're racing clockwise.
Your corporate logo police probably won't be happy though.
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Hi Sam,

I've swapped a couple of half pieces for a straight:

From the original idea by RichG

According to UR3 (unverified!):
16*Radius 4 curves (C8235). 30*Radius 3 curves (C8204); 6*Half Straights (C8207); 1*Quarter Straight (C8200); 16*Straights (C8205)
2,79m*2,80m. Track1 = 15,58m; Track 2= 16,07m

There are always trolls who will moan about the lanes being unequal. Maybe a handicap can be built into the program on the shorter lane?

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Adjusting the laps to compensate is certainly messy. A flyover is a solution but I can't see how to get it in easily or how to twist a figure of 8 into an RS shape.

Actually, if you put a couple of straight crossovers in (C182 classic track), according to UR3, the tracks become identical at 15.85m but you may get some crashes and there's a dead spot. Also, I don't think they are made now and you would need 4 half straight classic/sport track converters - not recommended.

There are some crossover curves (C8203) in the newer Sport track but they are Radius 2 so in addition to the collision risks and cars clipping the plastic x, they limit the max speed as one side is actually sharper than radius 2, so again not recommended.
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It's a bank holiday today in France so it's your lucky day.

Eh voila, equal tracks:

According to UR3 (unverified!):
17*Radius 4 curves (C8235). 29*Radius 3 curves (C8204); 4*Half Straights (C8207); 1*Quarter Straight (C8200); 15*Straights (C8205)
2.83m*2.66m. Track1 = 15.19m; Track 2= 15.19m

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Didn't realise you could do this in Ultimate Racer but it may be useful

Keep us posted.

QUOTE (Sam RS @ 15 Aug 2012, 15:59) <{POST_SNAPBACK}>Chris - was it an online order, or a phone order?Now I wonder what that parcel is that arrived at the local airport this morning from Birmingham?
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FB link above doesn't work for me. But if you search you find this:
but the "like" button to participate doesn't work yet. Also, I think you will have to agree to installing an app as well.

The cynical side of me says says it looks like they are trying to harvest the addresses of as many Twitter & FB accounts as possible, which they could then sell on and/or use for spam!

It's normal marketing these days I suppose, but maybe RS will be able to confirm otherwise.
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I see Doug has changed his link to the above, but anyway, when I click the Facebook page link: or on the "enter now" RS link on the Tweetcar link, I just get redirected to my personal FB homepage (I'm in France) using any of the 3 main browsers, even with the adblocker disabled.
So, is the competition only open to UK residents as I CAN see the Tweet Race sign up page if I go through a UK proxy server
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QUOTE (chris99 @ 28 Aug 2012, 12:19) <{POST_SNAPBACK}>So, is the competition only open to UK residents as I CAN see the Tweet Race sign up page if I go through a UK proxy server

OK I see you've waved your magic wand & it's fixed now. Thanks
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simultaneous posts!

Hi Sam,
It works now, but when I click on terms & conditions at the bottom of the sign up page I just get an error page.
QUOTE (chris99 @ 29 Aug 2012, 09:22) <{POST_SNAPBACK}>when I click on terms & conditions at the bottom of the sign up page I just get an error page.
Terms & conditions now visible - I see there are 10 velodrome sets to be won ...

I'll volunteer to take the actual race track off your hands for a fiver when the race is finished.

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The design winner is only 18 (Tom Speller)! Here's his design (not necessarily the final version?):

Source: blog

Source: Twitter

and fwiw, the code on his blog (not the final version):
CODEint track1 = 10; // track 1 PWM pin
int input1 = 0; //this is a interrupt input not a digital number (digital pin 2)
volatile int count1 = 0; // tweet counter for track 1
int car1Speed = 0;

int setReset1 = 1;

long track1Time = -500;

int speedSet1 = 0;

int track2 = 11; // track 2 PWM pin
int input2 = 1; //this is a interrupt input not a digital number (digital pin 3)
volatile int count2 = 0;
int car2Speed = 0;

int setReset2 = 1;

long track2Time = -500;

int speedSet2 = 0;

int carTime[] = {500, 450, 400, 300, 150}; // the amount of time the car will run on each tweet.

int carSpeed[] = {120, 160, 190, 210, 230};

int serialValue[] = {0,0};

int changeSet[] = {30, 60, 120, 250};

void setup(){

pinMode(track1, OUTPUT);
attachInterrupt(input1, track1input, FALLING);

pinMode(track2, OUTPUT);
attachInterrupt(input2, track2input, FALLING);



void loop(){

if(Serial.available() > 0){

int data =;
int currentNumber = 0;

if(data == '<'){

while(data != '>'){

data =;

if(data >= '0' && data <= '9'){
serialValue[currentNumber] = serialValue[currentNumber] * 10 + data - '0';

if(data == ','){
currentNumber = 1;

if(serialValue[0] > 0){
count1 = count1 + serialValue[0];
serialValue[0] = 0;
if(serialValue[1] > 0){
count2 = count2 + serialValue[1];
serialValue[1] = 0;

if(count1 > 0){
Serial.print(" , ");

if(count1 > changeSet[3]){
speedSet1 = 4;
}else if(count1 > changeSet[2]){
speedSet1 = 3;
}else if(count1 > changeSet[1]){
speedSet1 = 2;
}else if(count1 > changeSet[0]){
speedSet1 = 1;
speedSet1 = 0;

if(setReset1 == 1){
analogWrite(track1, carSpeed[speedSet1]);
track1Time = millis();
setReset1 = 0;

if(setReset1 == 0){
if(millis() > track1Time + carTime[speedSet1]){
analogWrite(track1, 0);
count1 = count1 - 1;
setReset1 = 1;


if(count2 > 0){
Serial.print(" , ");

if(count2 > changeSet[3]){
speedSet2 = 4;
}else if(count2 > changeSet[2]){
speedSet2 = 3;
}else if(count2 > changeSet[1]){
speedSet2 = 2;
}else if(count2 > changeSet[0]){
speedSet2 = 1;
speedSet2 = 0;

if(setReset2 == 1){
analogWrite(track2, 120);
track2Time = millis();
setReset2 = 0;
if(setReset2 == 0){
if(millis() > track2Time + carTime[speedSet2]){
analogWrite(track2, 0);
count2 = count2 - 1;
setReset2 = 1;


void track1input(){
count1 = count1 + 1;

void track2input(){
count2 = count2 + 1;
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Got to admit a certain fascination with this.

Are there enough tweets to get the car round the track yet you may be asking yourselves? Latest tally, 73 tweets for the red team and 59 for the blue.

New pics of Arduino unit here
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QUOTE (-Sy- @ 30 Aug 2012, 13:47) <{POST_SNAPBACK}>Link just takes me to my own facebook page.
Me too now - the link must be dynamically changing to protect the FB empire.

The new pics are on the Facebook RS components page news feed, half way down, under "Final testing of Arduino unit"
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