The STM32F030 (TSSOP-20) can be bought for around 1 Euro and an NRF24L01 module can be bought for about 2 Euro. Together these can be used to make a very low cost and very low energy sensor node. The chip is programmed using In System Programming (ISP) using a low cost USB/Serial converter. The programming circuit is shown here with the NRF24L01 module also connected. To place the STM32F030 in ISP mode, press Reset and ISP together. Release Reset first and then ISP. The STM32Flash program can be used to download code to the device. Further information on programming the device in this manner can be found here.

Mounting the NRF24L01 module

The NRF24L01 modules are great except for one problem: they have a double row connector which makes them difficult to use in a breadboard. Using some female headers which I got here the connection difficulties can be overcome quite easily. First, plug the connectors into the breadboard; one either side of the central valley.

Next, bend the headers so they form a female double row connector, plug in the NRF24L01 module and off you go!

Sample code

The first program is a port of this code which worked on the LPC1114FN28. It can be downloaded here. It communicates with an Intel Galileo Gen 2 base station and they simply swap 10 bytes back and forth. Details concerning the base station can be found on the page:
Using an NRF24L01 radio module with the Galileo and an ARM MCU
More examples to follow!
Back to my home page