Questions on Skywriter products


I’m just planning an order to place soon with the fever discounts. I am thinking of getting the Energenie board to control two sockets, and then a Skywriter / Skywriter HAT with which to control them. Obviously, you can’t stack two boards on the pi at once, so I was wondering if it was possible to fudge it at all. I can find from their documentation which pins the Energenie uses, and I was wondering which pins the Skywriter HAT uses so that I could see if I can use them together. I looked in the python examples on Github, but it was a bit hex-ey and confusing! The Skywriter no-HAT looks like it uses SDL/SCA (no compatibility issues here), and also something called TRFR, and I don’t know what that’s hooked up to on the HAT (and I’m assuming that they’ve got the same pinout here).

Secondly, the Skywriter HAT product page claims that it ‘Senses from up to 5cm away!’, but the Skywriter no-HAT says that it ‘Senses from up to 15cm away!’. I was under the impression that they were more or less the same thing, so why is it that one has a measuring distance three times that of the other?

One last question:
With the promotion, 10% off and a free RasPi for over £99, is the £99 the price of the order including the 10% discount, or after it? In other words, if I place an order for £100 worth of stuff, then get a 10% discount (ie I pay you £90), do I still get a free pi 2? Sorry if that’s confused you as much as it did me typing it!


for all your pinout needs (hum, we should add an overlay for the Pi-mote)

it looks like there is some overlap with the Pi-mote, however it should be trivial to change pin declaration in the Skywriter lib - as long as you use the non-HAT version or be creative with the HAT version that should work.

Regarding range I think 10-15 cm away will work with either Skywriter, but the smaller the board the harder it will be precise in x-y… if you should want to wave past the board then it should make no difference.

… last question, I would assume it is post-discount, I suspect including postage, i.e what the total you have to pay out is. Will try to confirm if I can grab one of the guy’s attention over the weekend.

Oh, I forgot had all your HATs on too :)

The energenie socket python script looks pretty easy to hack and change pin numbers too, and the board has a header more suited to desoldering (thru-hole).

Thanks for the (speedy) advice on the range and shipping.


Note that I edited my answer, sure you can hack the eurogenie script too, but if you went for the standalone Skywriter you wouldn’t need to, nor desolder the header on the Pi-mote.

I’m not sure what you had in mind to combine the Pi-mote and Skywriter HAT though, there is certainly scope like I said to be creative and get that working, be it through the use of a Black HAT Hacker, ProtoPAL, and any number of stunts and hacks I wouldn’t be last to consider :-)

to clarify, to redirect the transfer and reset pins in the Skywriter lib all you have to do is change SW_RESET_PIN and SW_XFER_PIN in

I’ve done it in the past to combine a Skywriter with a Propeller, works a treat!

True, I might go for the big Skywriter instead.

I was just considering the HAT version since A) it’ll probably be used with a pi, which saves effort as it’s a HAT and b) it’s a bit cheaper. I was planning to solder male jumpers to the pi-mote’s pins, and then plug them in to the needed stuff on the bottom of the HAT or solder wires from the bottom of the pi to the pi-mote.

I’ll do what you recommended to combine the two.


Note that the HAT is out of stock right now.

I personally have always felt that the non-HAT version finds its place in many more applications - size does matter when it comes to gesture applications, but I can totally see the HAT be adequate for controlling 2 sockets.

Out of interest, how do you plan to switch them on and off, flicking past one direction above the plane, or tap actions?

incidentally I just got confirmation that the £99 is total post discount. Orders go out with free shipping over £50 in the UK so it’s irrelevant to the equation, though if you’re outside I’ve been told order total inclusive of any postage cost is fine to be eligible for the free Pi.

Perfect. Order placed (I went with the hatless skywriter)

I was planning on trying different gestures and seeing what worked, but something like flicking was my original idea. I’ll post a picture and some code when I’m done.

I was slightly confused as to how to obtain the free pi, whether I had to add one to my basket or not prior to checkout. I didn’t add one, as I assumed it’d be added automatically. Was that right?

yep, I’m sure that’s how it’s done!

looking forward to the result, I’m always interested in Skywriter applications I hadn’t thought of before!


Ideally I’d somehow embed a Skywriter in the wall in each room, and have them all hooked up to a central pi to control lights. I’m not quite ready to tear my walls down though!

The back box for a light switch is 87x87mm, which is smaller than an A+ or Zero pi and a HAT. It might just be possible with a relay and tiny 5v conversion board, to squeeze it in to one of those and hide it away.


Is the Skywriter: 3D Gesture Sensing Breakout compatible with the pi zero w? It’s listed on the compatibility list for the Skywriter Hat, the previous version, but not on the 3d version.


It is!! I’ll update the product description accordingly. :-)

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thanks. I’ll buy it then :)

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I have ran the install script from github and wired up the skywriter accordingly but whenever I try to test it is working I get the following error output. Any ideas?

pi@raspberrypi:~/Pimoroni/skywriter/examples $ ls theremin.pd

pi@raspberrypi:~/Pimoroni/skywriter/examples $ sudo ./
Traceback (most recent call last):
File “./”, line 2, in
import skywriter
File “/usr/lib/python2.7/dist-packages/”, line 502, in
i2c.write_i2c_block_data(SW_ADDR, 0xa1, [0b00000000, 0b00011111, 0b00000000, 0b00011111])
IOError: [Errno 121] Remote I/O error
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
File “/usr/lib/python2.7/”, line 24, in _run_exitfuncs
func(*targs, **kargs)
File “/usr/lib/python2.7/dist-packages/”, line 493, in _exit
TypeError: ‘NoneType’ object is not callable
Error in sys.exitfunc:
Traceback (most recent call last):
File “/usr/lib/python2.7/”, line 24, in _run_exitfuncs
func(*targs, **kargs)
File “/usr/lib/python2.7/dist-packages/”, line 493, in _exit
TypeError: ‘NoneType’ object is not callable

That means it’s not seeing the Skywriter on the I2C bus.

Can you…

  1. post a picture of your wiring so we can double check that
  2. open a terminal, type sudo i2cdetect -y 1, press enter and paste/photo the output?

That should help debug stuff.

Cheers. It was bad soldering on my behalf. I have fixed it now.

my error is the same, and my wiring looks good, but when i do ‘sudo i2cdetect -y 1’ i get all dashes…can anyone help??

Can you post a picture of your wiring so we can double-check it please? All dashes means it’s not seeing the skywriter on the I2C bus, which is most likely a wiring issue since the board itself will have been tested before sale…