ESP IoT pHAT solder pads


OK…so looking at the ESP IoT pHAT in the image, the left hand solder pads are obvious (ESP GPIO, ADC and power) and, of course, the 40 solder pads to the right are for the Pi Zero header…

…but what exactly are the two groups of 10 rows of 3 solder pads (in the whitish-grey) rectangles for? Buzzing through with a multimeter it’s obvious each pad in a row of 3 is connected to the other but none of the rows seem to be connected to anywhere else on the circuit board.

I’m just wondering about the design thinking for putting them there and what the designers had in mind.



It’s a little prototyping area, equivalent to a breadboard. You can solder components there if you want to incorporate them into an IoT-type project, e.g. a temperature/humidity sensor.


I was wondering if that was the case. Rather than soldering components directly, perhaps using 6 lots of 10-way SIL female connectors could allow re-use (i.e., just plug components rather than soldering them). My main confusion is how anything in those pads would connect to either the ESP or Pi Zero pins.

Also, on an aside, there was a 10 pin SIL male connector supplied which I thought was for the ESP pins but there are only 9 solder pads for the ESP. Sure, I can trim off one pin easily enough but is that what it’s meant for?



The SIL connector is for the prototyping area, should you need it. You’d solder it so as to bridge the two sub-areas and add a row of pins on either side to use jumper cables to route signals out to the ESP breakout.

Here’s a different use of the prototyping space, designed to hook sensors with 3-pin landing:

… There’s quite a lot going on on the underside but it is mostly a matter of minimizing the number of links needed.


OK, thanks. I still think I’d probably just use female SIL connectors in the prototyping area - less permanent than soldering components directly.

On an aside, I notice CH_PD and GPIO_0 arent exposed on the ESP pads to allow connection between the two for ‘deep sleep’. Is there a problem with deep sleep and this pHat? Sorry, I realise that’s an unrelated question to my original post.