quinta-feira, 8 de maio de 2014

May 4th

Following the previous post, on this week I've been working on the software.

At this point I've developed two programs. The first program is responsible for the calibration of the sensors. This program receives data from the sensors and at the same time launches an interface, Figure 1. 

Figure 1 - Calibration interface menu.

On this interface it's possible to load an existing calibration or to create a new calibration. The load menu is for monitoring purposes only, while the new calibration menu is in charge of the creation of a new calibration profile. Upon completion of the profile, it's saved in a .xml file for future use.

The other program is the one that I mentioned on the previous post. I've made some changes and now after getting the data from the hardware it reads the .xml file, if there is any, and loads the calibration values. After this it calibrates all the incoming values and publishes them on ROS. Also, I added a launch file so it's possible to run the program using roslaunch command.


quarta-feira, 30 de abril de 2014

April 28th

On the past weeks I've been working on the Android App. I wanted to make an App that could communicate via Bluetooth with my setup. To create this application I've been using the Eclipse IDE with built-in Android Developer Tools (ADT). So far I've an application that have the calibration interface and the settings menu to setup the bluetooth. I've never had programmed in Java therefore is being a rather interesting learning process!

Last week, on Friday, my sensors have finally arrived! I got 4 Force Load Cells, 6 Force sensitive Resistors and 4 IR sensors, and their signal conditioning and acquisition board. 

Figure 1 - Phidgets InterfaceKit with 3 connected sensors and a LED for testing.

Figure 2 - Force Load Cell mounted in the pedal case.

Figure 3 - FSR with the signal conditioning board.

Figure 4 - IR Sharp sensor with the conditioning board.

The acquisition board is the InterfaceKit 8/8/8 from Phidgets, and to be able to collect all the data, it's required to create a program using the Phidget library. On this week, I've been making some changes on my ROS Package so it can read the data not only from Arduino but also from the Phidget InterfaceKit. At the moment the program get the data from the hardware asynchronously (IR sensor at 40Hz and the other sensors at 1000Hz) and publishes it on ROS. 
Next, it's required to add the GTK interface to calibrate the data, this should be capable of making the pedal calibration and save it into a file. After this the interface would be able to monitor the action on the pedals using the calibration file or not - Figure 5.

Figure 5 - Program scheme.


quinta-feira, 10 de abril de 2014

April 7th

Hello everyone!

On the meeting of the last week I've been challenged to make my project more flexible in terms of communication via Wireless. So this week I've been searching for bluetooth shields for Arduino. I've found some interesting devices like the Bluetooth Bee, that is a module with the XBEE design and size - Figure 1.
Also I've found a device that is a BLE 4.0 Module HM-10, that is smaller than the Bluetooth Bee and supports the bluetooth low energy 4.0 (BLE) - Figure 2.

Figure 1 - Bluetooth Bee.
Figure 2 - HM-10 BLE 4.0.

At last I've found the device that I think that would be the perfect one that is the BLEduino, that is a Arduino with a  built-in bluetooth module, however it's not available for sales yet!

Figure 3 - BLEduino.

To be even more easy-to-use I've started to learn and develop an android application that communicate via bluetooth with the system. At the moment the application is very simple but soon I hope that I'll be able to show you something good!


quinta-feira, 3 de abril de 2014

March 31th

On this week I've made some changes to my hardware.

As I said on my last post, I modified my acquisition board to a much more complete one. On this board I added the tension to current converter that will convert the sensor signal into current and send it to the receiving board that will have a resistor to convert this current to tension so the Arduino can process it. Also, because It's required to have the sensors isolated from the Arduino I added a DC/DC converter with isolation so I could have two different grounds.

Figure 1 - Complete acquisition board for 6 sensors (2 FSR, 2 IR, 2 Load cell) with V/I conversion.

The other changes are the JST-PH connectors that I added so that the board is prepared to install six sensors: two FSR, two load cells and two IR sensors. Also I added two RJ-45 connectors that will be responsible for supply and for sending data to the Arduino.

Also on this week I finally got my last prototype case of the sensors, with a few changes from the other drawing, and I found a pedal controller (used to play video-games) that is great to do some testing before I make it to the ATLASCAR.

That's all for now, I'll keep in touch!


domingo, 30 de março de 2014

March 24th

On this week I’ve been doing a several things. As in every project, it’s essential to have the documentation of all the work! This week I started to draw all the circuits of my hardware and to project the PCB Board in Eagle, as I said that I would be doing before.

The board is meant to be able to gather all the data from all the sensors, which are a force load cell, a force sensor resistor (FSR) and an infrared distance sensor, amplify the signal and convert it from tension to current. This last requirement is very important because the sensors will be far away from the Arduino. If the signal goes from the sensors to the Arduino in tension the signal may vary due to the resistive wire losses and as well, in current the signal has a greater electrical noise immunity.

The first board that I made, as you can see on the figure, doesn’t have yet this V/I converter so I’ll be making a few changes on the next week to add that.

Figure 1 - Acquisiton board made in Eagle Software.

Also the board has only three slots for one of the kind of sensors that I mentioned, however I’ll be using two of each kind so I’ll have to add more connectors too.
As for the connectors, I am using molex connectors but they are not the best considering their size and utility, so I’ll be switching those for RJ45 connectors for the supply and the signals, that able to have 8 wires in just one cable, and JST-H connectors for the sensors, that are much smaller than molex.

At the same time I’ve been creating a new package in ROS with a script in C++ that reads the data from the hardware and displays it as a kind of progress bars on ROS-RViz. 

Figure 2 - Displaying data on RViz, green - load cell, blue - FSR and red - IR sensor.


terça-feira, 18 de março de 2014

March 17th

On this week I will be working on Eagle which is a software that allows to project PCB boards, because later I'll have to make some of these boards for the signals acquisition.


quinta-feira, 13 de março de 2014

March 10th

On this week I did some drawings of my prototypes ideas and built a test prototype so I can be prepared to test and get data when the sensors arrive.

Figure 1 - Isometric view of the test case for the sensors.

Also I made a list to order all the equipment that I'll need the most for my project. For example, force load cells, force sensor resistors (FSR), IR Distance sensors and acquisition boards and adapters.