REV Robotics modules use connectors from Japan Solderless Terminals (JST) Manufacturing Co. These connectors provide smaller interfaces for motors and sensors on the modules. Below is an overview of the two JST connectors.
Motors: JST VH
Motor ports on the REV Robotics modules use two-pin JST connectors from the VH series. This larger connector features a clip to ensure a secure connection. These connectors are gendered, meaning there are male and female ends. This is in contrast to Anderson Powerpole connectors, which use physical orientation instead of gender.
REV Robotics sells the following ready-made cables and adapters:
- 2-pin JST VH pack of four cables, in 20cm, 30cm, and 50cm lengths for connecting motors with JST VH headers
- JST VH to Anderson Powerpole adapter cables for connecting motors with Powerpole leads
I/O: JST PH
Sensor and other I/O ports on the REV Robotics modules use three- and four-pin JST connectors from the PH series. This smaller connector may look familiar to some teams. However, please remember that the PH is larger than the connectors used on old TETRIX encoders and smaller than the connectors used on AndyMark NeveRest (and similar) encoders. Unlike the DuPont (servo) connectors previously used for sensors, the PH housings can only be inserted in one direction — so no more plugging in sensors backwards.
REV Robotics sells the following ready-made cables and adapters:
- 3-pin JST PH pack of three cables, with 20cm, 30cm, and 50cm cables for daisy-chaining REV Expansion Hubs
- 4-pin JST PH pack of four cables, in 20cm, 30cm, and 50cm lengths for connecting sensors with JST PH headers
- 4-pin JST PH pack of four joiner boards, for chaining two 4-pin JST PH cables
- Logic Level Converter, for both connecting a 4-pin JST PH cable with a 4-pin DuPont cable and converting between 3.3V and 5V signals
- Sensor Cable Adapter, for changing the order of wires in a 4-pin DuPont cable between a legacy sensor and a logic level converter
Please note that adapting sensors goes beyond the type of cable used; it also matters what voltages are used for signals.
Crimping JST Connectors
Most teams can (and probably should) rely on the cables and adapters listed above. However, crimping JST connectors is possible with a little care. The REV Robotics Expansion Hub Guide lists part numbers for the contacts, headers, and housings from the manufacturer and DigiKey, a recommended retailer.
Sidenote: contacts, or crimps, are the metal pieces that are crimped onto a wire. Housings hold the crimped ends and connect to the headers, which are usually mounted to a larger item like the Expansion Hub.
The following recommendations are based on personal experience. If you have different suggestions, please reach out.
For JST VH connectors, the Engineer PA-20 crimpers work well for experienced users. I prefer non-ratcheting crimpers, though it is important to understand the dangers of over-crimping and perform a few test crimps first. I’ve used the 2.3mm slot with good success (though based on this chart, the 2.0mm slot may be better depending on the size of the wire). If ratcheting crimpers are preferred, the BABAN Carbon Steel crimpers also work. For these, the 1.5mm2 slot has worked best for me.
The wire I commonly use has a large amount of insulation. As a result, the larger of the two VH contacts has been necessary. Be aware of the difference, and definitely test a few crimps before cutting a motor cable short.
For JST PH connectors, the Engineer PA-09 crimpers work well. As mentioned above, it is important to avoid over-crimping when the feedback of a ratcheting release isn’t available. For the PH connectors specifically, it is also very important to avoid crushing the end of the contact. Since the PH contact is quite small, it is easy to catch multiple parts of the contact in the teeth of the crimper.
