The past few months I’ve been working on the project for the Digilent Design Contest so I was quite busy. Together with my colleague Dragos I worked allot on this project but the results were great, our project the BlueRover won the 1st place so I say it was well worth it. First of all Digilent provided most of the parts needed for the project like :

  • 1 x Cerebot 32MX4 dev board
  • 4 x dc motors
  • 4 x HB5 motor drivers
  • wheels, metal pieces to put everything together

Besides these we also used:

  • 1 x LiPo 2S battery
  • 1 x 5V dc to dc converter
  • 1 x 6v dc to dc converter
  • 1 x BTM222 bluetooth module
  • 1 x MQ6 LPG gas sensor
  • 1 x MQ7 CO sensor
  • 1 x TMP275 digital temperature sensor
  • 1 x MMA7455 digital 3 axis accelerometer

The idea of a remote controlled rover excites almost every electronics student and when we heard about the Digilent contest we realized that we have the possibility to make such a project real. We decided to build our own remote controlled rover but it had to be different from what we’ve seen before. We came up with the idea that we could control the rover by using accelerometer data and that we could use a second accelerometer placed on the rover to sense the driving surface.

I handled the Rover with the sensors and my colleague took care of the control unit which is a Nokia E55 smartphone running a custom application in Python. The principle is simple the control unit sends acceleration data to the rover every 100ms thus controlling the movement of the rover. The rover reads data from the on-board sensors (CO, LPG, Temperature, Accelerometer, and Battery) and sends it to the control unit every 100ms. The control unit receives sensor data from the rover and reacts according to the rover accelerometer by vibrating on each bump sensed by the accelerometer. At the same time the control unit displays sensor data on screen.

I’m not going to go into details about the source code or the specs of all the boards we used in this project but you can find those in our report which I’m linking at the end of this article. I would like to add that Digilent RO did a great job in organizing this contest, it was a really great experience to be there and I’m sure we’ll be there next year too.

You can watch photos from the contest here:

Now I’ll leave you with a demo of our project captured right at the contest presentation:

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This article will be followed up by one dedicated to the BTM180 and BTM222 bluetooth modules from Rayson. Due to the lack of documentation on this module it was really difficult to get them working and I would like to share my experience for those who are facing the same issues.

October 1st, 2008

LED Pharmacy Cross

This article is part of the PCB Giveaway program that we have running here at Youritronics. Morgoth will get a free pcb manufactured by BKRtech for submitting this project. If you’re interested in participating, read more on the program page.

These days most pharmacies use LED pharmacy crosses posted at their entrance to let people know there is a pharmacy there. The reasons are obvious, they look cool&hi-tech, they can be seen from distance and they can be customized really easy (well, easy customizing pretty much depends on how the manufacturer approaches things).

If you try to search the web about schematics or example codes for this kind of circuit you wont find any, and again i think the reason is obvious, the crosses are quite expensive and so is the profit for the manufacturer. So nobody is gonna post schematics for such a project, unless you’re a hobbyist and you’re having fun with electronics.

The project consists of one ATmega64, three ULN2003 and five 57 LED matrix from Kingbright(TA20-11EWA). I had the idea to build something like this but so far i haven’t had the time nor the knowledge to get it done. So i asked Morgoth if he would like to participate in the project. I sent him the LED’s, the drivers and the PCB and he started working. As you can see not many parts are involved , but the secret lies in the microcontroller, it’s the programming that does the job.


In the next pictures you can see the microcontroller board with the ULN2003 darlington arrays:

LED Pharmacy CrossLED Pharmacy Cross

The circuit was designed to receive messages trough serial interface from a computer and than display them. Morgoth also designed a custom terminal for windows which provides easy access to the display.

In this test phase a serial interface by wire was used to transmit data between the terminal and the ATmega64, but a wireless or bluetooth module could be integrated with no problem.

Also as a note, the LED’s don’t light up really bright, for that to happen you need to use drivers on the positive rail. This also applies if you’re planning to take the project to another level and use bigger LED’s

And now, watch some videos with the LED Pharmacy Cross beeing controlled from the computer:

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WiTil - wireless accelerometer

This is the latest wireless accelerometer from SparkFun. The WiTilt v3 incorporates many new features including LiPo battery, built-in charger, enclosure, single axis gyroscope and many more! When combining the triple axis accelerometer sensor from Freescale MMA7260Q with the Bluetooth module from Roving Networks what do you get? The new, WiTilt v3 complete wireless Accelerometer Measurement System. All measurements are transmitted via a wireless Class 1 Bluetooth link that is extremely easy to use with a range of 100m (330ft) line-of-sight and 30m (100ft) in doors.

WiTilt – wireless accelerometer: [Link]

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