Hello,

I'm looking forward to use the digital outputs of the EZ-B to turn on/off a night vision camera installed on my Rovio... I'm a total beginner, as you can guess. I thought I could use the data wire to connect it to the base of a transistor, but I could not find a proper way, somehow I always ended up with a lower voltage on the emitter of the transistor... and the cam needs quite exactly 5V. Anyone knows how to use the EZ board to turn on/off some devices powered through it? That would help me a lot since I want to be able to reinitialize my robot (rovio Wowwee) when I'm away (the cam has a different IP and a built-in on/off switch that allow me to reboot the rovio... however sometimes the camera just shuts down (while the robot is docking actually...) so the rovio shuts down too. Therefore I use the EZ board as a safety circuit, more reliable, that would allow to reboot any device or circuit installed on the robot.

Bottom line : how do I get to power on/off a port on the EZ board ?

Thanks a lot.

To use the EZB to turn on and off external items such as lamps, cameras etc. follow the Tip120 & Tip122 Transistor Switching Circuit tutorial.

You needn't use the stripboard method however it does produce a nice and neat board. You can also put the components inline as mentioned further in that topic.

Ok, thanks a lot. I just saw your answer and I'm gonna look into the tip120 you mentioned. In the meantime I did something very... let say, "amateur" : I used a servo as a switch by attaching contacts to it! Not very satisfactory, though...

Another question : My EZ B disconnects and shuts down, for a reason that seems obvious and due to my amateurism : I connected two servo's circuits (striped from the servos provided into the kit) to the motors of my rovio so I can give more power to the rovio that became to heavy and now I can assist it when self docking by sending some juice bursts to maneuver properly. However, when it tends to turn off the EZB due to some current spike I guess. I of course thought of adding diodes to prevent power from rovio to go into the EZB but then I can change current direction so servos will work in one way only, which doesn't allow maneuvering. Do you know a way to prevent any current spike, knowing that Rovio's motor may receive current from both Rovio's power (different circuit/brain/power supply) and from EZB ?

My goal is to achieve a perfect telepresence with enough safeties to always be able to reboot any failing system remotely. I know that at the end I will always need a physical intervention but at least I'd like to prevent what is preventable, such as surge or power spikes or even some interferences that seem to make the EZB crazy at some point (I have many IP cams in my place to follow the robot wherever it could get stuck).

The best would still be a programmable circuit that would automatically reboot the battery pack or, even better, a DC internet enabled power switch. I have an AC power switch that allows me to turn off the Rovio untill the battery gets totally discharge so when I turn it off again it does restart the rovio. It takes two hours to achieve the process but at the end I gain control of the robot again, but it is useless with the secondary system made with EZB since it is connected to a battery pack that turns off itself once there's no more juice pumped out from it : you need to puch its button to -resend the juice again. If I could connect to the Rovio's different battery a little circuit that could be bluetooth or, better, wifi enabled, and built with an on/off switch connected to the EZB battery pack's on/off button, then I would have achieved such a goal.

The thing is that I could find nowhere any suitable Web/ip enabled on/off switch. Any idea on this one ?

Thank you again for your help.

Elfege

There is a company that provides free software so a PC can be assigned a single TCP/IP comm port. That same company also offers just what you are looking for: IP-Switch

I did follow your steps to make a switch circuit and it works. However I seem to lose around 1 volt in the process, any idea why? I used the exact same components as described.

CAN easy use a mosfet as a high current switch without any power loss or heat MOSFET IS LIKE A SWITCH its has very low ohms and any circuit can easy drive it

Another reason on using a mosfet you can easy use it as a high current switch and use a tiny low current spst to turn it on

LIKE if you want to switch a 10 amp battery you need a very big toggle switch ,but with a mosfet like 37 amp one ,you can use small low current toggle or pushbutton switch

Cant do it with switching transistor unless you use a big transistor and heatsink.

Thats biggest advantage of using a mosfet over a transistor

I just saw your answer, thank you !

REASON you are losing 1 volt is transistor,with a mosfet ,most are under .1 ohm or less Just like a regular switch is.

The circuit is the same for both. (e)emmiter on transistor is (d)drain on mosfet,the (c)collector on transistor is the (s) source on mosfet ,and the (b) base on the transistor is same as the (g) gate on the mosfet,N-CHANNEL is what type you need