Collective Orders

This page shall provide some information that we gathered during previous collective orders.

Re-check everything

Please note that the project is still in development, which means that changes in hardware or design are possible anytime. Before ordering parts, especially in large quantities, double check that the design you’re working off of and the list of items you are about to purchase match, and that neither is out of date or ahead of the other. If you print several devices only start printing in series after assembling the first one - that way you know that everything fits.

Ultrasonic Sensor Boards

The most sensible parts of the OBS are the two ultrasonic sensors. There are various models on the market, but most sold under the same name, JSN-SR04T.

AJ-SR04M

• Characteristics:
  • Resistor R19 is used to control the behavior
  • 8 MHz Crystal
  • Working Voltage: 3V to 5.5V
• Datasheet

AJ-SR04M: General PCB

AJ-SR04M: Model from collective order in February 2021

JSN-SR04T

• Characteristics:
  • Probably no resistor to control the behavior
  • Transverse IC on the connector side
  • 11.0592 MHz Crystal
  • Working Voltage: 5 V
• The datasheet found often cited on Chinese webpages is JSN-SR04T一体化超声波测距说明书.pdf (english translation).

JSN-SR04T: Front (1)

JSN-SR04T: Front (2)

JSN-SR04T: Back (1)

JSN-SR04T: Back (2)

JSN-SR04T-2.0

• Characteristics:
  • Resistor R27 is used to control the behavior
  • 8 MHz Crystal
  • Working Voltage: 3.3V - 5.5V
• Datasheet

JSN-SR04T-2.0

JSN-SR04T-V3.0

• Characteristics:
  • Resistor “mode” and the shorts “M1” and “M2” are used to control the behavior
  • 8 MHz Crystal
  • Working Voltage: 3.3V - 5.5V
• Documentation

JSN-SR04T-v3.0

SR04M-2

After some initial testing, it seems this model does not work in the OpenBikeSensor device.

• Characteristics:
  • unknown

SR04M-2