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Forum Home > Velleman K8055 Help > Trying to get an RC tank moving with the Velleman K8055

ozirock
Site Owner
Posts: 50

I've had a question from a guy trying to get an RC tank moving under the control of the Velleman K8055 usb interface board. His message is:

 

I am attempting to attach an RC Tank to the board but sadly I just can't figure out the circuitry, I've connected wires to the switches that control to the remote that controls the tank, and when I connect the two wires together the tank works fine. However, I'm not sure how exactly to connect them to the board, I've tried twisting all the negative wires together and inserting them into the 'GND' on the board, then putting each positive into the 8 digital outputs on the board, sadly with no luck.

 

I replied with a few questions and the answers were: 

 

When you test the board do the LEDs light up like you would expect?

Yes, all digital outputs 1 to 8 light up as expected.

.

Are you using the program from my site?

I've tried using many bits of software, including the program from your site (which could communicate with the board excellently by the way). I'm currently testing some software from http://k8055.info/?id=8 as my plan is to link the board up to the Internet so people from around the world can control the tank (yeah, too ambitious:)).

.

Did you take the battery out of the controller when you connected it to the board? (you need to leave it in because the digital outputs don't supply power)

I left the 9V battery in the controller, and the indication light on the controller lights up.

 

Are the switch's of the controller potentiometer type switch's or on/off switch's?

The switches on the controller are on/off microswitches, similar to these http://www.timeharvest.net/product_show/product_pic/VIDEO%20GAME%20SERIES/Microswitch/Small%20Black%20Microswitch.jpg

 

Just to update on the situation, I can connect the backwards/forwards wires and their grounds to the board and they work fine. It seems to be as soon as I connect the left/right grounds to the board it stops everything from working. I'm no electrician, but I'm perhaps guessing that the grounds are on some sort of different circuit and there is a conflict when the two are connected? (Just a thought)

 

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Ozi


Magical Machines

February 7, 2010 at 8:12 AM Flag Quote & Reply

ozirock
Site Owner
Posts: 50

I don't believe in too ambitious the worst that can happen is it doesn't work and you can always try again :) I had never seen that internet type software for the k8055, I'll definately be giving it a go when I get a chance myself.

 

I checked with my da who's an electrician and he said that if the controller has only one battery then there is most likely only one ground. He said you can check that the battery only has two connections, if it has three or more then it may be a special design for the controller and may have more than one possible at different voltages.

 

If the grounds are connected then one ground should work with any of the other positive wires so try using a wire you know is ground and test all the others against that wire and hopefully all the movements will work.

 

Let us know how you get on.

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Ozi


Magical Machines

February 7, 2010 at 8:16 AM Flag Quote & Reply

AdamS
Member
Posts: 9

Just thought I'd let you know I've signed up, I'll add some pictures of the tank and controller to this post later on. :)

February 7, 2010 at 8:24 AM Flag Quote & Reply

ozirock
Site Owner
Posts: 50

Thats great thanks very much, it'll be great to get to see the project in work. I'll also be posting a few pictures of my controller later but I think you have the right idea antway.

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Ozi


Magical Machines

February 7, 2010 at 8:34 AM Flag Quote & Reply

AdamS
Member
Posts: 9

Hmmm, just tried using one ground against the positive wires with no luck. It seems forwards/backwards has one circuit and left/right has a different one that causes some sort crazy conflict paralyzing all controls when in ground. I'll keep playing around but I admit it's not looking good. The battery has two wires that go to the power switch for on/off.

Do you know of any other suggestions that may help? I've never used the digital inputs, do you think they would be of use?


Luke.

February 7, 2010 at 9:52 AM Flag Quote & Reply

ozirock
Site Owner
Posts: 50

Thanks amazing, it sounds like it's short circuiting but how is a mystery, I wonder did they wire those buttons in the opposite way to the first set i.e. the wire we think is ground is actually a positive and the others are ground? Have you any way of checking that?


Have tried wiring up the part that doesn't work on it's own into the board?


Very tricky problem this.

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Ozi


Magical Machines

February 7, 2010 at 12:47 PM Flag Quote & Reply

AdamS
Member
Posts: 9

Just a quick update:

I've given up trying to wire left/right to the remote.

The tank can fire mini BB bullet balls at unsuspecting victims :) and I have managed to wire up the 'shoot' button.

Now my idea is that I'll have to have a wire coming from the tank for left/right and turret up/down control, which is not ideal but seems to be the only solution, although wires for the onboard webcam would be attached anyway. I just need to find a long wire with about 8 seperate wires internally, which could be difficult. I have found a long TV aerial cable though, so need to check if that would do the job.


The K8055 to web tutorial is about 50% finished, will let you know when its done.


Thanks,

Luke.

February 15, 2010 at 1:16 PM Flag Quote & Reply

ozirock
Site Owner
Posts: 50

Sounds good, you should be able to find a wire to suit no problem and it'd probably be a nice light wire too. I cant wait to see a video of this thing, controlling a tank from a webcam and you have a gun, it'll be the ultimate machine :)


Don't worry about the tutorial, there's no rush on it whenever you get a chance, getting your tank working is the main task :)

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Ozi


Magical Machines

February 15, 2010 at 2:28 PM Flag Quote & Reply

AdamS
Member
Posts: 9

Just another update on the project:

I managed to find the right cable with 8 cores in the form of the cheapest 10m ethernet cable on eBay.

I recieved it today, and after some consideration I ruined a perfectly good internet cable by tearjerkingly cutting off the plugs and was relieved to find 8 colour-coded small wires, I tested an LED on the wire and it worked excellently!

I'm really surprised at how durable and light the cable is considering the cheap price, I thought it would be solid and clunky but I think it will do the job greatly. I attached a picture below to show the wire cores in scale comparison to an AAA battery.


Click on image for HUGE version


Hopefully  I'll finish my college coursework tonight and have all weekend to get it connected and online, that is of course assuming I don't hit any more obstacles.


Thanks,

Luke.

February 18, 2010 at 1:58 PM Flag Quote & Reply

ozirock
Site Owner
Posts: 50

Great idea, that wire is perfectly light should work perfectly for you.


I know the feeling, I'm not getting much time to play with electronics at the minute because of presentations and projects, it's a real bummer but has to be done :)

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Ozi


Magical Machines

February 18, 2010 at 2:26 PM Flag Quote & Reply

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