K8055 - Dual Wiper Motor Control with Variable Speed

Thanks - that confirmed my thoughts
Your transistor has a different pinout than what I expected

no problem Kevin - it's always worth checking out the datasheet for your components for exactly this reason!

Tim

Minor setback
I have the circuit layout that Tim got from the Velleman forum bread-boarded and tested with a small 12vdc motor.
It will drive a small 12 VDC CPU fan with no problem with or without using the K8055 controller.
When using the K8055 PWM output, and the PC test program, the motor speed is controllable (as expected)
When omitting the K8055 the motor speed is full speed (also as expected)

However, I cannot get it to produce enough current to drive my DC wiper motor, with or without using the K8055 controller.

Some conditions...
I'm using a 10 amp battery charger right now as a power supply.
I'm using a 2n3055 transistor.

If I connect the CPU fan directly to the power supply, it takes about .35 amps to start and then runs with .27 amps.

If I connect the wiper motor directly to the power supply, it is taking 6.5 amps to start up and then runs with 4.5 amps.

If I connect the power supply to the Velleman circuit and attach the CPU fan to the motor outputs, it spins up, using the same .35 and .27 amps noted above while the transistor's temperature does not increase.

If I connect the power supply to the Velleman circuit and attach the wiper motor to the motor outputs, the motor does not spin, but I am seeing about .38 amps being used by the motor (and I also feel the motor humming). Additionally, the transistor starts to get hot if I leave it on too long.

Thanks for any help that can be provided.
Kevin

Hi Kevin - I have never heard of anyone using a battery charger as a power supply before... usually the type that charge car batteries give a very low trickle of charge over a long period - this is likely to be your problem.

As you can see from the attached video of one of my early actuator tests, a wiper motor controlled by the original velleman circuit adapted to work with my choice of components and powered only by a PC power supply has more than enough power to throw a 2.5m sofa around...

http://www.youtube.com/watch?v=grfrH1DTS20

Try a car battery or pc power supply as a power source - this will probably be enough. :thbup:

Good luck

Tim

OK - I'll give that a try

Thanks again!

Multiturn pot - superb performance with K8055

Hi to all!

As promised earlier in the thread:

I have now extensively tested, and can confirm that I am completely happy with the following 10Kx10Turn multiturn pot which is freely available from ebay (though you may have to get it posted from Hong Kong, which takes a bit of time!)

I got 5 for £21.99 (makes them about €5 each) and they are worth every penny :thbup:

They give a superbly smooth track of resistance into X-Sim via the K8055 - no jitter whatsoever, which makes for rock steady position control



As you can see from the diagram (which shows the side of the pot) legs 1 and 3 are for +5V and 0V, with leg 2 picking up the variable signal...

... weirdly enough, the numbering order of the legs as shown in the diagram above (and this is confirmed by the datasheet)
is 2, 1, 3 - remember that when wiring it up, or it just won't work!! 2 is the back leg.

Tim

A couple more offerings found whilst on the search for hardware:

100mm 10K Ohm slider potentiometer:

The slider is as smooth as silk, and gives an excellent trace into the K8055 (£4-£5ish)

Go to http://www.farnell.com , click on your country, and search for 100mm 10K


ALSO


1foot diameter (305mm) 1000lb (454Kg) Lazy susan

should be big enough to work with a tail slider rig - can certainly take the weight!!
definitely on my list of future developments... Super cheap too! - only $11.29 each!! :thbup:

Go to http://www.thehardwarehut.com/catalog-product.php?p_ref=258591

Tim

Tim,
I have been very successful in getting the board constructed and tested.
I'm optimistic that I'll be up and running soon.

However, I'm encountering one stumbling block:

Given the way the K8055 PWM output interacts with the relay board, as soon as you connect power to the board, the motor starts running.

As part of the Force-Profiler setup, there is an option to calibrate the system.
This involves connecting everything up: Computer -> K8055 -> Relay Board -> Drive Motor.
As soon as you connect power to the relay board the motor spins and the frame moves to the limits.

I 'm sure that this same behavior will happen when in game play mode. I'd feel much more comfortable if the drive motors did not receive power (and move) unless a specific signal was sent from Force-Sender.

Have you encountered this, and if so, how are you dealing with it.
As it is, I can only think to install a cut-off switch (removing power to the relay board) that will be in cut-off mode until I begin game play.

By the way - is seems that frequently at night, the x-sim website is down (at least for me here in the States). Are you seeing a similar behavior? For example, it was not accessible last night from 0200-12:00 GMT (approximately).

cool! :thbup:

Yes - this is because the PWM output of the K8055 is active low... to find out what this means, check out the K8055 manual, or Page8, Post10 of this thread for the relevant extract.

This is only a problem if you apply power without control... NEVER a good idea!!...
...or if you lose control (software crash) and this is why you need breaker switches with recovery diodes on you extremes of position
(OR a design that accommodates the over-run)

See Page6 Post4 for a video examining my early design, where this is taken into consideration and the over-run solution discussed.

For breaker switches at the extremes of position which act to stop the motors at maximum, and can be reversed when the setup is ready, See Page18, Post5 for explanation, and Page18, Post7 for video explaining how this works.

As before - never a good idea to apply power without control... I guess all you have to do is break the 12V power to the board/motors with a switch that you dont throw until everything else is ready...
... also, breaker switches just in case

Yes indeed - solutions as referenced above.

Remember also that it is very important to set your profile so that stop means that the pwm output is set to 100%

Keep going - from the sound of it, you're nearly there!

Tim

OK - that all make sense.

I do have cutout switches installed at the max point of movement along with recovery diodes so I'm good there

I'll work on installing a power shutoff switch between the the relay outputs and the motors.

Thanks again.

No problem Kevin - you are very welcome!

Tim

PS. I reckon it would be easier and cheaper to break the 12V supply to the relay itself, as you will have only have one set of wires to worry about then... if you put the isolator between the relay and motors, then you have 2 sets (one for each motor) which would necessitate a double pole double throw switch... the big red button breaker type switches I have seen locally to me have all been singles... going for the single break may improve your options

Tim,
I was thinking about adding another relay, but have the K8055 control it's operation:




This would ensure power is only sent to the motors if the K8055 is allowing it...
What do you think?

Thanks, Kevin

Hi Kevin - nice thinking... I reckon it could look like this for one motor (just double it up for 2DOF):
(Apologies for the hand drawn circuit - I am working on my pneumatic setup tonight so dont have time to do a digital version )



but (and here come the downers...) though it is an excellent solution, it only solves one issue... that of the motor spinning up before control is established. If the board crashes with the new digital output on, you will still have the same problem as before

I still think isolating the motor/power supply is the easiest and by far the cheapest solution.

Also, the extra relay/relays double the cost as the relay is the most expensive component (still pretty cheap though!), and unless you are using solid state relays (even more expensive) the clicking would drive you mad - 4 relays going for it would be quite some noise!

Tim

Those are definitely valid issues.

I'll still go with the relays (I can afford them if I get them via EBay for $5 US each) but I'll use a master cutoff switch to activate them.




That way I get the digital outputs back for other uses.

Yes - that will work too... another cool idea! :thbup:

For ways in which you could use the extra outputs, have a look at Page22 - just about all the posts are relevant

Tim

Tim
I just found this site,I can't beleave how far siming has come in the last 25 years.Im interested in your k8055.How can I get Intouch with you?

I have looked around the sight,My hats off to you sir you bring alot to this game.Thank you in advance.
Randy

Hi Randy

On contacting me, PMs dont work as I very rarely get to log in (except in the evenings)
that said, I always get to them in the end, and will always reply...

Better by far to just drop a post in either of the K8055 threads -
I'm always happy to help, but even more so if other people can benefit from the questions/answers :thbup:

Tim

Tim,
Im building a 3DOF flight sim.The flight deck is a full size (or real close) of a A-6 Intruder
so it will have sum mass to it.In addition to roll and pitch it will have yaw.It will be able to turn 360 degrees.
I have 3 Bodine 1/4 HP 115v 2.3 amp 38:1 gear reduction 48 RPM DC motors,that I hope to use pitch and roll.The motors will have a 6 arm and a bar that will attach to the table,and a spring loaded center post wilh a CV joint to take most of the weight.
The motors are new but fairly old.Theres 5 18ga wires on the motor,I have no clue how to wire these motors.and use your K8055.I have seen a simulator like the one I am building,with a completly inclosed cockpit made out of MDF so it has to be heavy,he is driving his X Y axsis with double wiper motors,driving a 23:1 manual steering box,per axsis.
Any help on how to wire these motors and use your interface would get me back on track.

Thanxs Randy

Hi Randy

I am just packing a case for the redeye tomorrow morning, but will give this setup some thought over the next couple of days... first thoughts, the relays will work just fine if you can find any heavy duty enough to do the job, but serious thought would have to be given to upgrading the rest of the circuit, and protecting the k8055 as the coil draw is bound to be greater than the allowable terminal limits...

I have just made the K8055 jump from 12v to 24v without incident for my pneumatic experimentation - in theory, a further step to 115v shouldnt be too difficult...

What you are trying to achieve sounds very similar to Jims setup - if you haven't already, you should check out:
http://www.jimspage.co.nz/intro.htm

I have toyed with the idea of creating a big motor version previously, but have always been focussed on maintaining a cheap solution... thinking about it, the relay board is now a reasonably mature solution - and is definitely super cheap, so its probably time to move to the next level! This will definitely be a good one for the thread!

The other thing I would say is that the K8055 can only control 2 motors per board with PWM and position control...
I have had some success recently with multiple K8055s, but being completely objective, my advice to you is that you should definitely read up on and very seriously consider Tronics AMC board.

Leave it with me - I'll see what I can come up with! :thbup:

Tim

Tim
Your right,Jim had the same Idea.Alot of people don't understand why I want It to be able to rotate 360 degrees.If you fly alot of IFR as I do,the simulator has to be able to turn your brain side ways to simulate flying at night,or in the muck.If the simulator can not make you motion sick,you can't simulate true IFR conditions.
I would love to see a thread on big dc motors.They have come down in price alot in the past couple years.I have about $80 in the three I have.The only bid differance in Jims sim and mine is Im putting a Chevy 4x4 front spindel between the top of the tube and CV joint so the plateform can rotate on nice big bearings and be driven with a #80 chain set up.I would be willing to help fund a high volt board if it would help.

Thanks Randy :thbup: