Today I am reviewing the HobbyKing V4 sensor shield as found HERE. Now, when I ordered this shield this was the only one available. However, I have noticed that they have other versions now too (the V5 and others that are just different colors.. Don't ask me what's up with that. I don't know).
If you prefer these shields they can be found HERE and HERE. I will mention some apparent differences in these later, but be warned, I don't have those boards.
When I got this shield I didn't really know what I was buying. I was completely new to Arduino, but I saw sensor expansion board and thought, "Yeah, I want to connect sensors." Well shows what I knew. The obvious fact is, you don't need this board to connect sensors. It just makes it more convenient to do so. It gives you nice male pins to plug all your sensors into.
The two things that really attracted me about this board was
A. It was cheap. $5.20 is pretty good.
B. It appeared to be made to connect standard hobby servos to the Arduino.
Well this is partially true. It is cheap. It is a great price. 5 stars there. But B. Well it does make it more convenient to plug servos into the Arduino, but if you are going to be running more than one servo, you will need to wire in external power. I will go over this in a later blog.
Basically the Arduino can only provide 40mA per io pin. Some people claim more, but don't tempt fate right? Servos can draw considerably more than that depending on the circumstances, size, etc. But let me say this,
This board does NOT allow for an external power source to be hooked up to power the servos.
There. You have been warned. The v5 supposedly does have some such deal that allows you to wire in power to the V pins (look at the picture) preregulator via the added screw terminal. I have no idea if this works well or not. I personally would do it myself and not risk it.
That is about it on this shield. It does do what it says on the box. I will note that it fits on the Mega. It leaves the back half of it open so that you can still access the unused pins. The only issue is that the I2C port is not on the same pins as on the shield(the shield is made for an Uno), so you will have to wire it manually (to pins 20 and 21, but that will come later). For an Uno it should work fine. In case you don't know what I'm talking about, that isn't a reason to get an Uno instead of a Mega. Still get the Mega. Its cooler.
- Price: I already covered. ~$5.00. Can't really beat that.
- Documentation: Well there isn't really any, but its kinda self explanatory when you get it. It just wires the io pins, 5V, and gnd to male pins for easy sensor connection.
- Quality: I have been very happy with it. It has lived on top of my Arduino since I got it. Very sturdy. All the solder connections seem good. I am happy.
- Durability: It has withstood me tugging at wires and such for several months. I would say it is on par with any other shield out there. I can't see you doing much better.
Overall, it is a nice shield. I would recommend it or the v5 to anyone. If you are trying to decide between the two, its really up to you. I'd get the v4 and save $5, but a valid argument can be made for both sides. I'm just cheap.
"I'm broke. Is this absolutely necessary?"
No. Of course it isn't. Get it anyway. You'll thank me later. I is an extremely useful tool and will make your life easier. Allow me to explain. I didn't buy real hookup wire. I use some extra wire (22awg I think) from when my dad and I replaced the garage door opener at the house. Well at some point I got over zealous with the wire strippers and nicked the wire. I now have a little piece down inside one of the gnd pins on... the shield! Not my Arduino. Yes this is a good thing. I'd rather break a $5 shield plugging and unplugging stuff than a $18 Arduino. It is also completely stackable (though not really functional to do so). Plus, it will fit nicely in a HobbyKing order with the Mega and one other shield. I know. I did this. Just get it. You'll thank me later.
So anyway. This should be the last of the long HobbyKing reviews for a while. Next I'll post some pictures and begin talking a bit more about what I did with these parts. I'll also list some other parts you might want to get (jumpers, resistors, etc.). There are cheaper places than Radio Shack. Trust me. So stick around.
Until Later,
Matthew