Magpie

Hi Hanzibal

 

On the subject of Oscillators here is a short app note on them. It seemed pretty good. Apart a typo on one of the schematics, where L1 uses a capacitor symbol.

 

http://www.euroquart.../tech-notes.pdf

 

I didn't find to much talk on symmetry though.

Here is the final schematic for the first spin and the BOM. The 0805 resistors I didn't bother getting the part numbers for. Same with some of the others which I already have. BOM was wrong, it has been corrected.

Hi Hanzibal I used Kicad recently, I found it fairly easy to learn, compared with Eagle anyway. Also it is open source and you are not limited in anyway. Both packages have their own bizarre UI way of doing things but you get used to it. I must admit I didn't get far with Eagle, I seemed to get a mental block whenever I open it up. With KIcad I followed some video tutorials and I have managed to do just about everything. The only thing I still haven't managed is to fill an earth plane in an easy way. But I managed to import all the eagle libraries, sparkfun libraries into Kicad and make my own library. Then layout a board that passed DRC by olimex. Although I got pinged 3 Euros by then for using non standard drill holes. I would use some form of source control with your drawings, libraries as it is quite easy to do things inadvertently. So the ability to roll changes back is critical. Diptrace is also supposed to be ok but I didn't try it.

Hi Just be aware that breadboards often have a break in contact along the power rails at mid point. If that is not it then you will have to get the multimeter out. I will give you a few suggestions, I am hoping one of them will lead you to the answer. Measure the correct DC voltage onto the little driver boards. Are they correct? Turn the power off and make sure you get DC continuity everywhere you expect it. especially GND and + 12. Also the analogue ground pin is connected in your circuit but I wouldn't use it as the track width may not be enough. Make sure the grounds between the 2 power supplies are well connected. Dont connect 12v from two separate power supplies together. just connect their GNDs. Your Gnd seems overly complicated. Each board should only need one gnd wire, I would try removing your ground wires that go with the Yellow and White wires. Use a star topology for the Gnd. based around your breadboards somewhere. ie. All grounds connect from this breadboard row.

Hi I am looking at the circuit now, I just wanted to say brilliant documentation, your problem deserves to be solved. What did you use to do it in? A few quick queries why does one motor say 12 volt 330 ma and the other say 4 volt 1200 mA? Are they separate power supplies or set to different current limits. You haven't mixed up the step and direction pins have you ( probably not but it needs to be checked). Have you tried disconnecting one motor entirely? No point really connecting two motors until you get one working. Do you have a multimeter?

I find it a bit tedious too, if it really doesn't want to cooperate Cancel any deploy that is happening. I pull out the usb Tell VS to Deploy app Wait 5 seconds plug in the usb

Have a look at Beagleboard

Hi all.

Mario is right, your circuit is not very realistic.
I think its a current limiter operating in the linear region of the mosfet, and the whole idea of pwm is to operate in the on/off regions, to save heat and power. I think what is needed is a mosfet driver. discrete mosfet driver

I know it sounds good to use discrete components, but for 16 or 30 channels it would be too much, too much soldering, and too much effort and to hard for someone fairly new to electronics.

I would like to give you some of my suggestions too, as I think there are ways your project could be done and it sounds like you really are keen, which is good.


Would we be able to go back to square one? I feel this is the only way I or anyone could make useful suggestions.

How big is the aquarium?
how much light does it need?
how many channels of light does it need? minimum and desired.
what colours are they?
what other functions are needed out of the netduino?
any budgetory constraints?

how is your electronics expertise?
how is your programming expertise?
could you construct, solder the circuits?
do you have many tools, an oscilloscope perhaps?


ps. For the record I have made a 3 channel hbled dimmer out of an attiny and discrete components. but it took a while to get right.
It is still operational.

ps. you need to be careful with the leds, when you are in development it is easy to blow them. very expensive. use fuses.

Hi Guiliano You need to tell us the electrical requirements of the valves in your backyard. Do you know? If you dont know then look for a model number and or manufacturer written on them somewhere. They may be controlled by relays using either Low voltage AC, like mine are, or by low voltage DC or by mains voltage. They may be also be actuator valves controlled by a motor, which would be more complicated. First I would find out the specs of your valves. You may then need some sort of relay output board or shield, but these are cheap so don't worry. Tell us what type of valves you have and then I could suggest a circuit/sheild for you.

Hi Reactive, Mario I think Reactive's query is more about AC and DC, as he is not sure he can drive an AC circuit with a DC control voltage. The answer is that you can drive an AC pump with a DC control voltage, because a relay is actually two electrically isolated circuits. One circuits switches a switch in the other circuit but no current flows between them. One circuit you could call the coil circuit, Reactive needs to use a Relay with a dc coil as he is going to turn the relay on and off with DC coming from the Netduino. Use the famous diagram, it works. Anything Driven off the Netduino will always use a DC relay. The other circuit is the load circuit, the relay's part of which is just the equivalent of an on/off switch. for Reactive he should make sure that the relay can switch 110v AC at the pumps rated current. Reactive you don't need an AC relay you need a DC relay(5 or 12 volt). The difference is on the coil side. Both sorts of relays can switch both AC and DC loads but be aware that the voltage and current ratings for the load will be different and so each relay should come with ratings for both AC and DC loads.