Hi All,
Got this circuit off the net which makes sense to me.
I have the lower transistor connected to one of the Arduino's digital outputs.
The lower resistor set to 200ohms.
Can't make it work... 
Someone please take me out of my misery and throw an hint as to why it's not working XD
[EDIT] this circuit can't work. please see posts below
TIA,
Pedro.
Its nonsense... Where did you get it?
Is it mechanically or electrically latched ?
Hi michinyon
Thanks for picking up. 
It's a Hunter solenoid (9V) magnetically latched. So yes, mechanically 
It requires inversion of current for "open/close" and it latches on its current position via a spring/magnet combination.
It's the "current inversion" part that I'm stuck with as I'm primarily a programmer and still kinda electronics noob
What I really want to achieve is a circuit that I can control the opening/closing of the solenoid via a single arduino pin.
And that without any further current consumption after each "pulse" (need ~50ms) as this project is battery powered.
BR,
Pedro
Been thinking about controlling it via a DPDT relay, preferably one with a 5V coil.
Found this on Ebay: http://www.ebay.com/itm/1-x-Relay-5V-1-25A-2-Form-C-DPDT-2-Contacts-Free-Shipping-/180966617444?pt=LH_DefaultDomain_0&hash=item2a22737164
It can switch up to 1,25A which is more than I need.
I drew a circuit around this relay (in attachment). Also there's a gEDA schem for those who use it.
Asking if this will work and if the cap (ceramic) is well positioned.
TIA,
Pedro.
latching_solenoid_control.sch (1.87 KB)
R2 = 10K ? Emitter follower ? No diode ? Where are these crazy circuits coming from,
again this is nonsense.
Mark I do appreciate you picking up the thread... Only wish you could lend a more constructive hand though
As I said I'm a programmer ... so please bear with me as I'm still in the process of learning electronics
This is the revised circuit with a flyback diode (in attachment) - which should have been included from the start. Made a H-Bridge with the DPDT.
BTW I didn't pick this one off the net... Sometimes one just have to look away from the screen and think about what has been learnt so far 
It's kinda working (i.e. solenoid not firing up as reliably as it should) as I only have a 2200uF cap at hand. I included a 4700uF in the schem as I very much suspect I need a beefier cap to account for the solenoid's bobbin charge time.
ATM I can say it's working. With spectacular low amps I might add
[EDIT] still very much open to constructive criticisms though
TIA,
Pedro
