9 years, 7 months ago.

Ideas on selecting the appropriate microcontroller (Advice needed)

Hello everyone.

I would like some advice, that would be great! I'm working on a little project for my ranch that goes like this:

First; tagging livestock with very small bluetooth transmitters for tracking within the ranch (keeping track where and if one goes missing).

Second; placing receivers in areas which can pick up the bluetooth transmission data and re-transmit the data up the line to the ranch house.

Third; the receiver in the house would collate the data and display the results

I figured I would go with Class 2 or Class 3 for the bluetooth devices.

With all these amazing products which would be the most economical with a very small footprint to make the bluetooth receiver from.

1 Answer

9 years, 7 months ago.

Isn't the range of bluetooth limitted compared to some other options? Or is the idea that the receivers location is used to track the location of the livestock? (Wouldn't you need alot of receivers? And you retransmit then with something else?)

I would assume you want for the devices on the livestock and for the re-transmitters a low-energy solution also? A core M0 will be the most logical solution. I have looked only a little bit into Nucleo energy consumption in deepsleep, but from what I measured IIRC I wasn't really impressed (probably due to the code base). But how much that matters also depends on the consumption of the rest of your system.

So you are going to need to figure out which requirements those devices have to meet exactly, and I don't know how much RAM/flash you are going to need for your code. The LPC812 is small and low power (https://mbed.org/platforms/NXP-LPC800-MAX/), maybe a bit too small and low power though. LPC1114 is also quite small (if you don't take the DIP package), waking it up from deepsleep with a timer isn't ideal, but a library exists which should work. And one where you might start your considerations is the KL05Z (https://mbed.org/platforms/FRDM-KL05Z/). Very small and low power, and more powerfull than the LPC812. If you end up needing larger devices you can either look at the LPC11Uxx series, or in the case of the KL05Z you can upgrade to one of its larger family members.

This is all assuming with small footprint you mean of the IC, where you want to make your own PCB. Otherwise have a look at: https://mbed.org/platforms/?form-factor=6. In which case you end up either with the LPC1114, LPC11u24 or LPC11u35.

Hello Erik and thanks for the advice...

Yes and yes, the bluetooth is limited to about 100 meters (Class 1) but v4.0 BLE uses very low power so batteries are not an issue. I would place receivers at many locations which would re-transmit to other devices until is gets to the home base (miles away). Looking at the LPC800-MAX and the FRDM-KL05Z they both could work I believe, I would need to put a bluetooth V4.0 BLE device them. The LPC11u24, LPC1114 and LPC11u35 could also work and would also need the attachment bluetooth. I'm not sure how much space I will need for the program but not much I would guess. I figured I would use the FRDM K65 to prototype the system then I can figure out what resources are required. Still... I feel that there might be a small microcontroller board with the bluetooth integrated that would work but I guess it might not be mbed enable.

posted by Scott Douglas 02 Aug 2014

The only real mbed board with bluetooth integrated is: http://mbed.org/platforms/Nordic-nRF51822/. Stupid I forgot that one :P. Then you have a single chip solution.

posted by Erik - 02 Aug 2014