During november we basically worked on testing nrf24L01+ modules in order to understand their possibilities and to decide if it was the best option for our project.
Although we don’t have a very clear picture of the final shape of the project, what we do know is that we want to to use simultaneously more than 8 modules receiving and sending data of the body in movement. Some modules will be attached to the body and the others over our future robots.
This post will show to you our different versions of the PCB module that we’ve developed, and at the end you will find a link to download the latest one. Feel free to send comments or whatever info you want. Tnx.
Our first steps in this project began by looking for solutions, libraries, etc. We had already tested the nrf24l01+ during Citlali’s Fab Academy course, and this month we dedicated our time to extend the practice and research .
We also found the existance of the mini nrF24L01+ modules, so we ordered immediatly a pack of 15 of them. This is completely great, as it reduces the size of our PCB. 😀
– NRF4201+ is a very cheap radio transceiver module that works with 3.3 V. It has a built in antenna and a voltage regulator that allows the module to tolerate 5v inputs. These modules include all the elements that the radio needs to function: oscillator, mixer, power amplifiers, low noise amplifiers, filters, antenna.
-Please take a look at Learn! Do! useful site with eeeeverything you want to know about this module.
-We decided to use it as it allows to create a network and a mesh of modules, naming each one with an ID.
-More info about nrF24L01+ on our CINESTESIA WIKI.
-NRF24L01+ are about 2,25 Eur each one
-miniNRF24L01+ are about 1,3 Eur each one
Redesign PCB, this is our version No. 4.
Attach and test mini nrF24L01+
Attach and test lippo batteries
-2 Lipo Batteries (3.7 V each one)
-Voltage regulator 5 a 3.3
-2 Capacitors (10uF each one)
– 0k Jumpers
-10 K Resistance
-MPU6050 – breakout GY521
We worked on the design of a shield that could allow us to attach the radio module and sensors to the body.
The connections that we followed for wiring up nrF24L01+ were based on the info in this site: HERE!
ICSP connections can vary depending on the Arduino Model that you are using, we recommend taking a look at AMTEL’s microcontroller datasheets and testing connections with your multimeter.
We have useful diagrams for NANO and UNO connections on our CINESTESIA WIKI.
Mentioned quickly in our last post.
Here we wanted to use 2 cell batteries to feed the Nano microcontroller. We read somewhere that the RAW pin could be used as a VIn , but this didn’t work for us. By hand we removed the copper trace from VCC to RAW and soldered a wire.
We draw in Rhinoceros the Arduino Pins and imported it as a DXF file into Eagle so we could place whatever pins we needed in the correct position.
//4th Version (latest one)
We worked on a 2nd and third version based on this one, adding different connectors. We can say the best by far is the 4th version where we decided to move the “Arduino Nano” to the back of the copper sheet so we could reduce the module size.
Eagle view with annotations:
We are using FabModules to generate the GCode for machining with a Roland SRM20.
Our little army:
Fab Lab Barcelona
Eagle Files: mini nrf24L01+ pcb shield