I am a student at Virginia Tech and for our project we are using the Pololu - 75:1 Micro Metal Gearmotor HPCB 6V with Extended Motor Shaft (Pololu - 75:1 Micro Metal Gearmotor HPCB 6V with Extended Motor Shaft) with the Pololu - Magnetic Encoder Pair Kit with Top-Entry Connector for Micro Metal Gearmotors, 12 CPR, 2.7-18V (Pololu - Magnetic Encoder Pair Kit with Top-Entry Connector for Micro Metal Gearmotors, 12 CPR, 2.7-18V). The trouble is we’ve had a lot of issues with the connection between the two parts. The solder joint for some reason never seems to hold great and we end up getting bad readings on the encoders or the motors turning uncontrollably. I was wondering if anyone had any recommendations or tricks for the soldering as what we’ve been doing seems to not work well. I see there are new motors with the encoder preinstalled which would have been awesome but we’ve already accumulated a large amount of the old kind so can’t really justify buying new ones right now.
As a general starting point, I recommend making sure you are familiar with the practices outlined in the Adafruit Guide To Excellent Soldering since those should be applicable to anything.
For our Micro Metal Gearmotors, I recommend that you tin both motor terminals with a little bit of solder before you trying to solder the encoder. Please note that holding the soldering iron against the motor lead for too long can damage the motor brushes, so I recommend only applying heat in 2-second intervals or so. If the first few attempts do not go well, pause and let the motor cool a bit before trying again.
To attach the encoder board, start by adding just enough solder to tack one terminal, making sure the board is centered on the back of the motor so the shaft does not rub against it. Then, with the tacked terminal helping to hold the board in place, make a full joint on the other terminal before going back to complete the first joint.
Lastly, I recommend adding some kind of strain relief to the encoder cable to prevent forces on the cable from being transferred to the soldered motor terminals.
