Got my TOUGH DECISIONS email, any more detail on shields available?

So I got my “TOUGH DECISIONS” email through today asking me to pick my combination of Spark Core(s) and shields. I’d hoped to see some more information about the different shields as part of this phase of the project but, if anything, there seems to be less info online now than when I backed! O_o

My main questions are:

  • is the relay shield rated for UK domestic supplies, ie. 240V/50Hz?

  • what’s the maximum safe current to pull through each relay?

  • Judging by the image above, the battery shield just seems to be a cell connected directly to the micro-usb socket on the Spark Core itself, is there anthing more to it than this?

  • Is there any charging circuitry? Indeed, is the cell rechargeable and/or user-replaceable?

  • Is there an On/Off switch as with the Shield Shield?

  • the Shield Shield appears to have a voltage regulator on it, but no barrel connector, as per a regular Arduino, and there’s an On/Off switch. Where does it get power from?

I’ve got no use for the JTAG Shield, but am unsure what to pick from the three others. Hopefully some answers to the above will help.

Good questions! I would like to know more about the Battery Shield as well.

Picture of shields

Since it’s not letting me edit my post, I’ll reply with more info here:

Current Shields:

  • Shield Shield - Converts the footprint and pins of your Spark Core
    into that of an Arduino, making it compatible with all of your
    existing Arduino shields and accessories.

  • Relay Shield - Control any
    normal outlet or high voltage electronics product to switch your
    existing electronics on and off from anywhere! Turn your AC on when
    your close to home. Switch off the lamp in your living room from
    your couch. Be really mobile and/or really lazy. (relays appear to be cRUus which just means they are recognized by UL for Canada and USA for some standard… Spark will have to clarify what the specs are… maybe a datasheet would be helpful)

  • JTAG Shield - For
    the deeply technical, use the JTAG Shield to flash code directly to
    the microcontroller on the Spark Core. If you’re an embedded
    software expert, you want this.

  • Battery Shield - Wireless projects
    need mobile power. A simple 3.7V battery connects to this shield for
    solder-free integration with the Spark Core.

Ah, right, 3.7V for the Battery Shield would suggest it’s a Li-Ion, then, and rechargeable.

Honestly we are speculating here… but my guess is the battery shield is just a JST connector that wires up to the RAW and GND inputs of the Spark Core. What would make it 100 times more useful would be to add a second row of headers just to the outside of the ones already on the board. Then you get power, and can play.

Obviously if the other side had a USB connector and the board had a recharging circuit that would be sweetness. My guess is that it doesn’t though… hope I’m wrong.

All of the shields are currently undergoing a second revision. [quote=“WiteWulf, post:1, topic:261”]
is the relay shield rated for UK domestic supplies, ie. 240V/50Hz?
The answer is yes.

The relays are rated at 10A / 250VAC.
Here is the datasheet:

We are including a battery monitor/charger block in the new revision. Haven’t really gotten around identifying that part yet. Inputs are welcome!

There is no ON/OFF switch on the battery shield

Good catch! The current version just has 2 pin headers for supply input. Here are the proposed changes to the new version:

  1. Addition of a barrel jack
  2. Logic level translator on all digital I/O pins (3.3 <->5.0)
    In addition to this, the user can always power the Core via its USB connector

I hope this answers most of your queries.


Thanks for the info @mohit :smile:

Just when I thought I’ve heard of most foreign relay mfgs, I get surprised by another.

FWIW: I would personally stay away from Goodsky relays. I recently compared the internal construction to Song Chuan relays and they were pretty bad. Song Chuan is comparable to American Zettler and Tyco… albeit maybe not quite as good. I would suggest cracking the case off of one and really checking it out… scrape the contacts down and see how much nickel is really on there, it shouldn’t just be plated… check the welds on the braid, pin thickness, etc…

Another thing to consider, many of the cheaper relays have a higher pull-in (aka pick-up) voltage. Typically 75-80% of the rated voltage, vs. better relays that have a lower pull-in voltage around 50%-60%. When you get really serious about a design these types of things can start to matter.

As for the Battery Shield… battery charger/monitor would be awexome especially if it included a cut-off circuit to prevent the battery from discharging too far (if available and cheap enough).

@BDub Yes, there are so many of such manufacturers out there! I’ll run a quick test on them and see where they stand. Good call on hacking them open.

Hi, When do you think this would be confirmed as a new feature ? (Best case Assuming it will be)… I am looking at adding a translator onto the SPI Interface for 3v <> 5v but would not need to if the shield shield could do it for me !

The design of the new version is underway and the translator is a confirmed feature on it!

For the battery shield monitor/charger, I’d like to suggest something that would handle energy harvesting as well as USB for charging the battery. For example, something like the TI bq24210 won’t break the bank and will run the load while charging the battery off a solar panel, miniature windmill, hamster-powered wheel generator… I can see a lot of uses for these devices as remote sensors and having a way to recharge them in the field would be very useful.


I have the newer versions of the battery shield and the relay shield. What I would like to know is, does the battery shield charge the battery when the core is attached to the relay shield and the only power source is over the barrel connector of the relay shield.