Alternative hardware

Main board

Alternative Pycom boards, such as older LoPy boards or FiPy boards, are not currently compatible with our software, due to having fewer UART buses.

FiPy

The faster and more powerful FiPy board also consumes slightly more power than the LoPy4.

1MB

Pycom_002_Specsheets_FiPy_v2.pdf

pdf

Expansion board

Pycom expansion boards can be used in place of an FTDI cable for updating firmaware or downloading software onto the LoPy4.

Pytrack

179KB

pytrack-specsheet-1.pdf

pdf

Pysense

179KB

pysense-specsheet.pdf

pdf

Exp 3.0

492KB

expansion3-specsheet-1.pdf

pdf

Custom Grove PCB

Feel free to edit the Eagle files for the custom Grove PCB and tailor it to suit your needs. You may also simply wish to leave some pads unpopulated if you don't need them for your application.

Temperature and humidity sensor

Temperature and humidity data are required for accurate calibration of the air pollution data. The SHT35 module we used has high sensitivity and uses I2C communication. Alternative sensors can offer lower costs or additional information, such as pressure.

	SHT35	DHT11	BME280
Price	$13.90	$5.90	$17.00
Temperature	-40 - 125°C (±0.1°C)	0 - 50 °C (±2°C)	-40 - 85°C (±1.0°C)
Humidity	0%-100% (±1.5%)	20%-90% (±5%)	0%-100% (±3%)
Pressure	N/A	N/A	300-1100 hPa (±1 hPa
Interface	I2C	Digital	I2C/SPI
Currently supported?	Yes	No	Yes

SHT35

DHT11

BME280

Micro SD slot

There are 3 options for populating the micro SD on the PCB:

1. China standard micro SD slot (surface mount pins at back)

2. Europe standard micro SD slot (surface mount pins beneath cover)

3. 8-pin header for micro SD breakout boards

China standard

If you're buying the PCB from a PCBA service, like Seeed Fusion, this will probably be the slot you'll populate. The pins sit at the back of the micro SD slot, so they're not too difficult to hand solder. However, these can be difficult to purchase from UK/European suppliers and the lead times from China are often very long.

Europe standard

These are the easiest surface mount micro SD slots to obtain in the UK, from suppliers like CPC Farnell. However, the pins are quite tricky to hand solder, especially if the top cover extends over them.

Be warned that the product may differ from the image online. You may be forced to cut off part of the cover to access the pins for hand soldering.

Breakout board

Using a breakout board is the easiest option if you want to hand-solder the entire board. However, it is also the most expensive choice.

We recommend soldering an 8-pin header onto the base of the board and using it in combination with an Arduino micro SD breakout board. We chose the pin arrangement of the Arduino breakout board because it is well documented and easy to obtain from reputable suppliers. Additionally, many electronics enthusiasts may already own the board.

If you wish to use an alternative breakout board, with different pin ordering, you'll probably want to solder wires directly between the PCBs.

To protect the boards and prevent short-circuits, you might want to stick some electrical tape between the PCBs.