Speed Controllers
Moderators: BeligerAnt, petec, administrator
- peterwaller
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Re: Speed Controllers
Just found a slight problem with the Rx31 receivers.
The channel outputs are just about 3v which is OK but if it is loaded with a servo it comes down to about 2.2 volts which is a bit boarder line.
On my controllers to stop the motors running until the link with the transmitter has completed I check the weapon channel which is the one with the failsafe.
If there is a servo also connected to that channel sometimes the micro controller doesn't see the pulses and although the servo still works the motor drives are held stationary.
The problem can be fixed with a pullup resistor but I thought the info may be of use to anyone using the recievers.
The channel outputs are just about 3v which is OK but if it is loaded with a servo it comes down to about 2.2 volts which is a bit boarder line.
On my controllers to stop the motors running until the link with the transmitter has completed I check the weapon channel which is the one with the failsafe.
If there is a servo also connected to that channel sometimes the micro controller doesn't see the pulses and although the servo still works the motor drives are held stationary.
The problem can be fixed with a pullup resistor but I thought the info may be of use to anyone using the recievers.
- peterwaller
- Posts: 3213
- Joined: Fri Feb 15, 2002 12:00 am
- Location: Aylesbury Bucks
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Re: Speed Controllers
I can't remember where or who it was but someone was asking about a UK supplier of the TB6612FNG which is the motor drive chip I use in my controllers.
I see HobbyTronics now supply them at £2.4 each.
http://www.hobbytronics.co.uk/motor-con ... tor-driver
I see HobbyTronics now supply them at £2.4 each.
http://www.hobbytronics.co.uk/motor-con ... tor-driver
Re: Speed Controllers
Thanks Peter, they actually started to stock them after I contacted them to see if they could get them in for me. Superb service can't recommend them enough!
- peterwaller
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Re: Speed Controllers
The controllers I have been building to date are extremely labour intensive especially making the actual PCB which have to be etched hand drilled and then each plated through hole has to have a rivet inserted a soldered both sides. To try and improve this situation I have finally bitten the bullet and worked out how to generate gerber files so my next controller will hopfully have properly manufactured PCB's. I am working on a design which will include the Lemon DSM2 compatible receiver and will be fully plug-in. There will be a 6 way connector for power and motors plus the normal for mine 4 way servo plug.
The modules look as they will come out about 30x31x10 mm excluding connectors and I am aiming for a target price of around £40 + £2 P&P, which includes the Rx, but will depend on PCB and other costs which are yet to be fully sorted.
The modules look as they will come out about 30x31x10 mm excluding connectors and I am aiming for a target price of around £40 + £2 P&P, which includes the Rx, but will depend on PCB and other costs which are yet to be fully sorted.
- BeligerAnt
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Re: Speed Controllers
Haven't tried these guys, but saw them mentioned in an article somewhere. Not sure how much shipping would cost if spending under $50, but at less than $10 for 10 boards it's got to be worth investigating!
http://www.seeedstudio.com/depot/fusion ... Path=70_71
I've used PCB train (Newbury Electronics) for work, good service but the prices are probably a bit too high for this.
http://www.pcbtrain.co.uk/
http://www.seeedstudio.com/depot/fusion ... Path=70_71
I've used PCB train (Newbury Electronics) for work, good service but the prices are probably a bit too high for this.
http://www.pcbtrain.co.uk/
Gary, Team BeligerAnt
- peterwaller
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Re: Speed Controllers
That does sound cheap I had already ordered mine the reason I didn't want to commit to the price was not knowing if the gerber was completely correct.
Anyway the boards arrived today and they look really good just need to build one and test it.
I went to these people
http://www.ebay.co.uk/itm/PCB-Manufactu ... 3a863b7e2c
Who turned out to be
http://www.southdowncircuits.com/home/4579960401
They came out at £63 inc P&P for 20 PCB's so just over £3 each but infact they must have made spares as they sent me 27 PCB's and turned them round in 6 working days instead of the 10 quoted.
Can't fully build them yet as I am still waiting for the 6way connector and wiring loom from China but can fully test out the board.
Anyway the boards arrived today and they look really good just need to build one and test it.
I went to these people
http://www.ebay.co.uk/itm/PCB-Manufactu ... 3a863b7e2c
Who turned out to be
http://www.southdowncircuits.com/home/4579960401
They came out at £63 inc P&P for 20 PCB's so just over £3 each but infact they must have made spares as they sent me 27 PCB's and turned them round in 6 working days instead of the 10 quoted.
Can't fully build them yet as I am still waiting for the 6way connector and wiring loom from China but can fully test out the board.
- peterwaller
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Re: Speed Controllers
The board all seems to work OK but I really need to put it in a robot to fully test it.
I have fitted a 7 way connector with one pin missing for now while I await the 6 way ones which is why the connector sticks out past the end of the board.
Top of board showing controller components.
Bottom of board showing Lemon Rx attached.
Finally with a cover.
Weight with case is 7.2 gms increasing to 11.2 gms when you add the loom and battery connector.
I have fitted a 7 way connector with one pin missing for now while I await the 6 way ones which is why the connector sticks out past the end of the board.
Top of board showing controller components.
Bottom of board showing Lemon Rx attached.
Finally with a cover.
Weight with case is 7.2 gms increasing to 11.2 gms when you add the loom and battery connector.
Re: Speed Controllers
I can see a lot of people throwing that massive connector away and soldering straight to the pins or the board. I would . Good for a beginner, the big white connector, but perhaps a bit bulky for the rest of us.
- peterwaller
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Re: Speed Controllers
I did look at a smaller one on half the pitch but the wires were a bit on the thin side.
As you can see it is shorted then the servo connector so when you consider you have saved three of those with there assocated wire and a seperate receiver I think you will find it is not too bad.
Obviously people can always take off the connector but soldered wires do tend to be unreliable so you would invalidate any warranty.
I will look and see if I can improve it if it doesn't involve a board change.
As you can see it is shorted then the servo connector so when you consider you have saved three of those with there assocated wire and a seperate receiver I think you will find it is not too bad.
Obviously people can always take off the connector but soldered wires do tend to be unreliable so you would invalidate any warranty.
I will look and see if I can improve it if it doesn't involve a board change.
- peterwaller
- Posts: 3213
- Joined: Fri Feb 15, 2002 12:00 am
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Re: Speed Controllers
By drilling the connector pads and fitting rightangle connectors, and moving the receiver to the other side of the controller board I have now got them within the 30 x 31mm size but the the thickness has increased from 10 to 12.5 mm.
Right angled connectors.
Receiver mounted on component side of controller.
New unit cased.
Cable loom and servo connected.
I will bring the two prototypes to the AWS so you can see the size but I don't think I will ever convince David to have connectors.
Right angled connectors.
Receiver mounted on component side of controller.
New unit cased.
Cable loom and servo connected.
I will bring the two prototypes to the AWS so you can see the size but I don't think I will ever convince David to have connectors.