Circuit revisions
I have revised the circuit and posted the new schemo on my website
DC brushed drive page
Most of the revisions are to do with the drafting errors I mentioned before, plus I made the layout a bit neater.
One major change is that I figured a way to include on board charging for a 12V SLA without increasing the cost of the project. To do this I changed the pre-regulator to an L200C current limiting voltage regulator and configured the board so that you can use a simple jumper to select its function: as pre-regulator (like before) or as a battery charger. You will need more heatsink capacity for the battery charger option as the current limit is set at around 500mA.
I am going to get a second set of prototype boards made before I commit to the full run, the board house says 4-6 days.
I have revised the circuit and posted the new schemo on my website
DC brushed drive page
Most of the revisions are to do with the drafting errors I mentioned before, plus I made the layout a bit neater.
One major change is that I figured a way to include on board charging for a 12V SLA without increasing the cost of the project. To do this I changed the pre-regulator to an L200C current limiting voltage regulator and configured the board so that you can use a simple jumper to select its function: as pre-regulator (like before) or as a battery charger. You will need more heatsink capacity for the battery charger option as the current limit is set at around 500mA.
I am going to get a second set of prototype boards made before I commit to the full run, the board house says 4-6 days.
C Controller, motor & partsHi Mark
I read earlier in this thread that you plan to use a Maxon motor in your design. You may already know this, but there is a Maxon distributor is Australia. The manager knows quite well what motors are suitable for turntable applications. Last time we spoke, he indicated that a suitable budget motor starts at about $30 and that premium models can go to over $100 each. It has been a while since we spoke, so I cannot help with model numbers or other details. PM me if you need the contact details.
I read earlier in this thread that you plan to use a Maxon motor in your design. You may already know this, but there is a Maxon distributor is Australia. The manager knows quite well what motors are suitable for turntable applications. Last time we spoke, he indicated that a suitable budget motor starts at about $30 and that premium models can go to over $100 each. It has been a while since we spoke, so I cannot help with model numbers or other details. PM me if you need the contact details.
I've dealt with M Rutty & Co several times over the last few years for various reasons and Brett is quite helpful. I bought an #110191 from them about a month ago, this is the motor for which the controller was designed and with which I am doing the testing and development work. It is probably the most suitable motor in their lineup if you want to run at around 600RPM, the #226764 is better at 300RPM, as explained here:
http://www.members.iinet.net.au/~quiddity/audio/DCbrushed.html.
Since SuperHKM has kindly offered to source the motors and can get them cheaper than I can, I am leaving that to him.
My email server has been down since Thursday so I have not been able to contact Vinyl Addict to ask about pulleys. If you are reading this, could you work out how much it would cost to make 20 pulleys of 17 mm diameter at the outside of the crown, machined in say 6061? Also how much it would cost to make the pulleys in 30 mm diameter? I would think that approximately 6mm between flanges would be appropriate for a 5mm belt.
http://www.members.iinet.net.au/~quiddity/audio/DCbrushed.html.
Since SuperHKM has kindly offered to source the motors and can get them cheaper than I can, I am leaving that to him.
My email server has been down since Thursday so I have not been able to contact Vinyl Addict to ask about pulleys. If you are reading this, could you work out how much it would cost to make 20 pulleys of 17 mm diameter at the outside of the crown, machined in say 6061? Also how much it would cost to make the pulleys in 30 mm diameter? I would think that approximately 6mm between flanges would be appropriate for a 5mm belt.
I went to the post office today and asked them directky, as their web-info leaves something to be desired.
Maxon 110191 $90
For USA shipping $ 23, totaling $113
For Europe shipping $ 14 totaling $104
look ok ?
A friend of my caugth interest, and I now need three boards complete with deluxe parts.
Maxon 110191 $90
For USA shipping $ 23, totaling $113
For Europe shipping $ 14 totaling $104
look ok ?
A friend of my caugth interest, and I now need three boards complete with deluxe parts.
Bas Horneman said:
Based on the replies to my previous posts the majority want speed selectability / adjustability so it becomes the standard. Obviously if you don't want it you don't have to use it.
As it stands at the moment the pair of PCBs will cost $USD17, if you round that up to $USD20 as per markgall's suggestion I would appreciate it. This includes postage if I can send them in an airmail letter.
The "deluxe" kit to populate the PCB will add $USD66 for the parts. Postage is $USD10 as there is no way I can pretend it's a letter, so the total including PCBs and postage is $USD93, you could round that up to $USD100.
The board has the charger circuit on it and the kit includes all the parts for it. You will need to provide a power supply and the battery itself. The power supply is unregulated, 18V DC at >500 mA, the battery is a 12V SLA of >4 Ah, both of these are pretty cheap and easily available. If you don't want to use the battery the charger circuit also works as a pre-reg to bring the 18V (unregulated) power supply down to 13.8V.
The second prototype boards are due for despatch today, I should have them tested by the end of this week. I will then place the orders, we should be good to go in two weeks.
As I understand it I can email a PayPal request, so I need everyones email adresses. Perhaps easiest if you collect the addresses Bas? I am having serious trouble with email at the moment, I decided to purchase my own domain name and will set up new account this week - probably info(insertampersand)quidditytech.com.
I have no problem with that. So sure.
You can use the email button to reach me.
In the header of your email please put "Mark Kelly Controller"
Please send me your
DiyAudio username:
Paypal address:
Amount of PCB:
Sets of parts to populate the PCB's:
Once I've got them all together I'll forward the data to Mark Kelly.
There are two boards.
The main board (75 x 100) holds the controller. It has a three wire connection to a second board (63 x 75)
The second board allows the motor speed to be selected (two speeds) and adjusted (independent adjustment for each speed).
If this feature is not required a trimpot can be inserted instead of the 3 pin connector on the first board.
The reason for the two board layout is simple - the main board goes on the back panel of the enclosure (which can double as heatsink), the second board goes on the front. If you wanted one board layout the encloure would have to be exactly the right size.
The second set of prototypes should be here soon, I will post phots once they are built, this should make it easier to see what I mean. I will also prepare a full construction guide and post it.
The main board (75 x 100) holds the controller. It has a three wire connection to a second board (63 x 75)
The second board allows the motor speed to be selected (two speeds) and adjusted (independent adjustment for each speed).
If this feature is not required a trimpot can be inserted instead of the 3 pin connector on the first board.
The reason for the two board layout is simple - the main board goes on the back panel of the enclosure (which can double as heatsink), the second board goes on the front. If you wanted one board layout the encloure would have to be exactly the right size.
The second set of prototypes should be here soon, I will post phots once they are built, this should make it easier to see what I mean. I will also prepare a full construction guide and post it.
Bas Horneman said:
To keep the cost down I got the board house to panellise the PCB prep so they will deliver equal numbers of main boards and adjustment boards. There is therefore no cost reduction if anyone wants only the main board.
superhkm said:
The tallest part is the L200C reg, I have placed the reg and the two power transistors so that they can all be mounted at the same height, they are equally spaced to make cooling easier. On my prototype I have them mounted on a 3 x 20 x 125 strip of aluminium which makes the total height above the board 25mm.
The controller dissipates 2.5 watts when running on battery power. The charger dissipates about 3 watts at the start of the charge cycle, less at it enters float mode. My suggested wiring arrangement is to switch between charge and run, they never run at the same time.
If you use the prereg circuit instead of the charger the total dissipation rises to about 4 watts.
My aluminium strip as above is adequate rather than ideal as a heatsink. Vinyl Addict has the first prototype mounted in a Hammond aluminium chassis with a back panel around 100mm x 50mm and this apparently works OK.
I am looking at sourcing some aluminium chassis which are 160mm x 75 mm x 2mm thick, this will provide very good heatsinking.
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