Which HAT do I need to build this IR transmitter?


I own a Raspberry 2 B+ and I’m about to build an IR transmitter to replace my remote. The project and the schematic are presented in details here : http://alexba.in/blog/2013/06/08/open-source-universal-remote-parts-and-pictures/.

I need direct access to gpio pins. So, I think that excludes Explorer Hat/Pro. I was thinking to get the Propeller HAT because it seems to give access to direct gpio pins, 5V vcc and 3.3V vcc, and that’s all I need. But I just want to be sure before placing my order. Will it work ? Or should I get an Adafruit T-Cobbler with a classic mini breadboard ? I’d rather go with the Propeller HAT as it fits perfectly in the pibow coupé. I don’t want a breadboard hanging around my RPi.

Thanks in advance for your help !

Hum, a HAT, by definition, does not allow direct access to GPIO, as the specs do not cater for stacking. Some however, like the Explorer/Propeller, do indeed provide a breakout for some of the pins, but not all.

I’m confused though, why would you need one of those HAT involved for your project?

I just want a hat because it fits perfectly on a Pibow Coupé case.

If I get a breadboard ad a Cobbler, it doesn’t fit on a pibow coupé case and it will hang around, it’s just not practical under my TV. Unless there is seach a breadboard that fits on a case ?

iMO, you really shouldn’t build a permanent solution on a breadboard, wires are bound to get loose.

These will provide clear from the USB/Ethernet ports if that is what you mean by fitting the Coupé:


You could even stick a breadboard on top if you really wanted to, though again, soldering in permanent position is what will give you the least trouble long term.

Ok then, I will listen to you and I will solder directly on adafruit Perma-Proto. My main concern is that if I wrongly wire the schema, will I be able to undo and solder again or I need to buy another Perma-Proto?


Desoldering single points is not that much of a problem. I haven’t tried the perma-proto myself but expect the contacts to be high quality and survive such treatments.

You only need the ‘No EEPROM’ version incidentally. In fact you might want to consider using a stackable header such as:

That way you can add an Unicorn HAT or some other HAT at some point. Depends how tall your IR is though, but could work.

Thanks RogueM for pointing me this link ! It’s nice because I do not solder directly on the Raspberry but on that HEADER, right ?

I will also get a breadboard for testing out my connections before soldering directly on the pcb. Gosh I haven’t soldered anything since my studies, 10 years ago !

No, you’d still use the perma-proto breakout to access the GPIO you need, but using a header with extra tall pins allows you to stack a HAT on the top of your IR circuit if you wanted to at a later point.

… That’s just a suggestion though, since you have a choice of which header to solder to the perma-proto. Soldering the header that comes with it will be slightly easier, but this will give you room to expand.

Sorry, I misspoke what I wanted to say. I thought that HEADER would clip directly on the RPi, and then I would solder my perma-proto on it, rather than soldering the perma-proto on the RPi itself.

Sorry for the spelling mistakes, I’m a french guy ;-)

Oh, yeah, I wouldn’t recommend soldering directly on a RPi2.

… I speak French btw, so if you get stuck feel free to PM me, though your English is perfect :-)

Oh thanks :) I think it’s better to continue here for sharing informations to those who face the same questions, even if it would be way more convenient for me to speak in french :)

So, to sum it up, I need :

  • The HEADER that connects to the RPi - no soldering required. It allows the HAT to be placed on top of USB/RJ45 port
  • The perma-proto hat - need to be sodered to the previous HEADER

Is that right ? Though I’m wondering why I would need that particular HEADER as it seems that there’s already one bundled with the perma-proto hat mini kit. In fact, I don’t plan in the near future to stack other hats.

And finally, would that fit in the Pibow Coupé ? Or I need to let my RPi naked ?

Thanks for your helpy mate.

Yes, the perma-proto comes with a header. If you don’t plan to add a HAT then the other one is not necessary. Be aware that you will not be able to desolder a 2x20 header later on though.

The pibow Coupé brings in no particular physical restriction, from the point of view of access to GPIO or attaching add-on boards it is very much like having a bare RPi.