Socketing the “Pro Micro” Controllers
While the Pro Micro-like controller modules (Frood, nice!nano etc.) can be soldered directly to the PCB using the included standard header pins, it’s often practical to make them removable. This is achieved by using controller sockets and pins. This is especially desirable with wireless builds where the small batteries are put underneath the controllers.
- If you want to put a small (usually 301230 size) battery underneath the controllers, you have to choose sockets high enough for the battery to fit (see below)
- Any sockets will work for a wired build
We have several types of sockets available:
- 💲💲💲/ ⭐⭐⭐ Mill Max 315 low profile sockets. These are very low and will not allow a battery to fit underneath the controller. They require thin pins, for example the Mill Max 3320 ones. They look very neat and are high quality, but they are quite pricey
- 💲💲/ ⭐⭐ Generic medium profile sockets. These are a bit taller and fit a battery up to 3 mm thick underneath the controller. The sockets are actually taller than 3 mm, but the controllers are traditionally installed in the upside down orientation, i.e. component side towards the PCB, which means the USB-C socket will reduce the amount of available space underneath. These sockets also need thin pins. They are a bit cheaper.
- 💲/ ⭐⭐ High profile sockets. These are quite a bit taller still and allow batteries up to 4.5-5 mm thick to fit. They are very budget-friendly, also because they don’t require additional pins – they work with the standard square header pins included with the controllers
Most of the socket/pin packs are sold in two different versions:
- Pack for standard 24-pin controllers (nice!nano, Pro Micro etc.) – 2x 12-pin sockets + 25 pins
- Frood pack that covers the extra I/O pins along the bottom edge – 2x 12-pin sockets + 1x 5-pin socket + 30 pins
You only need the Frood pack for kits specifically designed for the Frood and making use of the extra I/O pins (e.g. Cantor Pro Frood, Cantor Pro MX or Lumberjack Pro Frood). Standard kits designed for the Pro Micro or nice!nano will work fine with the standard pack, even if using the Frood.
Installing the Sockets
- Put the sockets into the correct footprint (set of holes) – pay attention especially with reversible split keyboard PCBs where there are two sets of footprints on the PCB
- Either use a bit of kapton tape to fix the sockets to the PCB (the bronze tape which is heat resistant – normal packing tape will probably melt and leave a bit of a mess), or just hold them in the PCB and carefully slide them onto your work mat with the PCB upside down to prevent them falling off, and put some stuff underneath the PCB so that it sits level.
- Solder one pin near the middle of each socket. Check the alignment of the socket and if it doesn’t sit at the right angle directly on the PCB, reheat the solder and fix the position of the socket
- Solder the remaining socket pins
Installing the Mill Max 3320 Pins
- If you have some kapton tape (the bronze heat-resistant tape), stick a short piece over the sockets. This will prevent the solder to stick to the sockets in case it leaks from the controller holes when soldering the pins in. However, this is not necessary – you just need to take care and use only the required amount of solder
- Insert the Mill Max 3320 pins into all the socket holes. It’s best to use small needle nose pliers. The first insertion takes a bit of force, so be careful not to bend the pins
- Put the controller over the pins in the correct orientation (usually upside down). Solder two pins in the opposite corners while paying attention to the controller position and making sure it sits flat on the sockets. ⚠️ Only use the minimum required amount of solder to prevent it from leaking from the bottom of the controller hole which could attach the controller to the socket permanently (especially if you didn’t use the kapton tape on the sockets). The solder only really needs to fill the controller hole. If you follow that rule, there’s little risk
- Solder all the remaining pins
