My own Version of Mark Kelly's Speed Controller

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Here my version 1.0 of the Mark's Kelly DC Motor Speed Controller. Since I missed the original Group Buy, and that Mark said that he didn't want use to copy is PCB layout, I design my own PCB. Mark also mentionned that his schematic can be use freely.

I did a few modifications since my own application was slightly different as well:
-Internal Battery charger, no more wall adapter.
-Just one speed supported.
-Battery included inside the controller case. Provision for an external battery connector if a outside bigger battery is needed.
-Design a small PCB to contains the two switches and the leds battery charger conditions. Included the blue power on led as well.
-The case will be make of brush aluminium and birch plywood and will match my Tecnodec platform look because they will sit side by side.

Here the PCB. The notch on the side is where the 2.2AH battery will be located.
 

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Yes. I can post the PDF file if they are not too big. I was able to buy fro 2$ a nice little 12V DC motor to try my own motor controller PCB. I don't want to try my prototype on my actual turntable motor, just in case.

The prototype is about 50% tested. I found some corrections to be done on the PCB. The last version 1.2 will incorporate these corrections. I'm working on the enclosure. It will be done in birtch plywood to match my turntable insulation platform look.
 
Here the PCB's fitted on the base plate with the battery, before I assembled the casing slices.

The enclosure's top will be made of a sheet of brush aluminium. The bottom is rigid, made of 1/8 alu. The transistors heatsink L-Shape piece of aluminium (seen on picture) further increase the base plate rigidity.

The Led & Switched small PCB can be seen on the front. To access the inside of the controller, I just need to unscrew the base plate and slide out gently the base plate. The front PCB allows the led and switches to just slide-out of the front panel.
 

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I installed a rear plate on the back to receive the connectors. I will also have access from the back to the speed multi-turn adjustement potentiometer. The piece of alu is inserted into the wood for a better look.

The casing top slice can be seen also on the picture. It is mostly complete except for the top battery clearance space.
 

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I'm gald to report that I completed the testing of my prototype pcb and corrected the few mistakes that I made :angel:.

The circuit is working just fine with a small 12V motor. I will try it this weekend with the real turntable if possible.

This is the latest version of my PCB, ver 1.2 that include all the corrections. I also added a fuse for the battery and reduce the pcb lenght.
 

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This message is for Mark Kelly. Hi Mark, remember a few months ago I was building my own version of your controller PCB. It is completed now and it is working fine with a little 12V test motor, Rmotor of about 100R.

However, when I tried to use it with my Michell Tecnodec turntable motor, the circuit is no longer working. I trace the problem to be a too high motor current demand for some of the circuit component values.

This motor is about 25.6R, and need 9.6V to gives 33rpm. I was able to get 9.6V fine with the little test motor, but if I tried the much higher load of this motor, the current drop of the first serie resistor of 4R is way too high and I don't have enough voltage left to drive/control the motor.

Can you give me some suggestions on what part value to change to get this circuit working with this motor? I already started to troubleshoot the circuit. I remove IC4 and I tried at least to get 9.6-10V at the output, without current compensation.

Thanks for any help you can provide.
 
pcb boards

Hi,

Do you have the pcb designs for this, can you sell it? can you send them to me, I am building my own turntable and your design seems impressive.

If possible you could also send me 1:1 scale printouts in pdf so that I could make my own boards, no need for silkscreen or solder mask.

Many thanks and regards.
 
I have been working on a new version of the controller which incorporates a greatly improved compensation circuit and a method of cancelling drift. I believe the new circuit is patentable so I am pursuing IP protection at the moment.

It is, unfortunately, very much more complex and will not be an upgrade from the original as the two circuits are incompatible.

On the other had the new circuit will operate without the drift cancellation (which requires two extra boards) so it could be made as "DC controller lite".

Now that I've finished my AC controller circuit I can concentrate on the DC circuit, hopefully it will be available as soon as I have the IP issues sorted.
 
This is not a group buy, but just this particular user that wanted to have his own pcb made using my own PCB design gerber files. I just made my PCB's myself because I'm doing it only in single quantity for myown personnal use. If anyone else want to do his own PCB, I can send you my gerber file. It is easy to do. Read the post because my own PCB design has some difference from Mark Kelly version, for one, it has only one speed, 33 rpm and has integrated battery charger supply and charge leds circuit.

For any more commercial offer, please refer to Mark Kelly. He's the original designer and he own the design.
 
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