Open-Source multipurpose interactive embedded systems Microcontroller kit

[wedo]

Hello my Friends,

I would like here to post a design of an Open-Source multipurpose interactive embedded systems Microcontroller kit for laboratory education.



The kit development aimed at designing a universal training board that can cover a wide range of experiments for the electronics, communication, control, and power departments of the electrical and electronics engineering.


The kit has followed in the designing process all standards, so it can utilize any AVR MCU or any SPI protocol compatible one. The MCU programming can be done by all GNU based compilers with both low-level (ASM) and high-level (Basic, Pascal, C, or C++.) MCUs programming languages.

Many peripherals have been placed on the board to enrich its universality. About 70 different experiments (on basic, intermediate, and advanced level) have been developed.

There has been 47 peripherals unit selected and the units were placed on the board in a way that saves a comfortable working space and separates the elements of each unit from the other units.



Since a good planned student-centric approach has proven effectiveness in engaging students, the experiments manual was designed in a student-centred manner, so that the students can perform proceed with the experiment and develop the aimed skills without a need of teacher supervision.

A detailed description including schematics, experiments, and How to Build recipe have been made available for the students as an open source to enable them to build their own board, and give them even more deeper centric role in this experiential part of engineering.

It is planned to put these resources on the web making the prototype available to implement for any practicing engineering student. It is hoped that the open source approach will attract academic staff and/or students to develop more experiments based on the rich peripheral components of the kit.

The average cost of building our board is about 120$, while any similar commercial kit will cost more than 700$.

Selection of the designed experiments has been taught in Spring 2008/2009 for about 65 students in the Electrical Engineering faculty at Aleppo University.

So, here we go. I will put the whole system between your hands.

I will start partitive posting (section-by- section) here in order to avoid very long page.

I will try to post the:
-   Schematic and layout design.
-   Information about the peripherals and design.
-   Experiments and source codes.

P.S. Unfortunately the manual and hands-on course are in Arabic language. I've plan to setup them in English soon.

If you have any question about the design, please don't hesitate to replay!

Wedo,

[spasbyspas]

Hi "wedo", congratulations to project! Will they support the project, keep with the theme! For interpreter use http://translate.google.com

[wedo]

The Kit Block Diagram:

The MCU ATmega128 is the kit core and it is linked with the kit peripherals such as a Liquid Crystal Display LCD through I/O ports. It is linked with the kit serial communication units, e.g. CAN, RS232, USB, RS485, PS2, I2C, and 1-wire through the serial interfaces. It is linked with the analog sensors, e.g. temperature or pressure, through Analog to Digital (AD) convertors. It utilizes the external interrupts I/O ports to interface with the switch buttons and the rotary encoder. The serial port I2C is connected with the data memory EEPROM (AT24C512 chip), and the real time chip RTC (DS1307 chip).

The serial port SPI is connected with the programming unit (STK300) of the MCU and the voice chip APR6016, it is also linked with an MMC card and a data flash memory (AT25xx). The serial port UART0 is connected with USB interface (FT232R chip) and with COM port through RS232 protocol for facilitating PC connection. The serial port UART2 is connected with a CAN port for facilitating industrial communication purposes. The Figure below shows the kit block diagram. All peripherals that needs external communication with the surrounding world are linked to the grey boxes.



Posted on: September 26, 2009, 08:04:23 08:04 - Automerged
Here below Some of the Hands-on Experiments that can be done with the kit:
1.   Programming the MCU ports for displaying LEDs light movements
2.   Interfacing switches with the MCU ports
3.   Interfacing 4x4 Hexadecimal Array Keypad (16key) with the MCU
4.   Interfacing and programming the MCU with a 20x4 LCD
5.   Interfacing and programming the MCU with a 128x4 GLCD
6.   Interfacing and scanning Quad seven-segment display
7.   IR remote control sender/receiver based on RC5 code
8.   Data Transfer using RF Transmitter based on FSK modulation
9.   Interfacing and programming the MCU with Real-time clock chip
10.   DAC by Interfacing 8-bit ladder network with the MCU
11.   Programming the MCU analog comparator unit
12.   Digital Frequency counter/meter 1HZ – 4MHz
13.   Measuring the luminous intensity (Flux) using LDR
14.   Measuring the barometric pressure and altitude using a Barometer
15.   Interfacing with the LM35DZ analog temperature sensor
16.   Storing Data using MMC/SD card in FAT23 format
17.   Programming Smart-Card with high-security software algorithms
18.   Interfacing and Programming 32x8pixel LED-Matrix scrolling Display
19.   Speed control of DC motor using  PWM
20.   Interfacing the MCU with PC using RS232 protocol
21.   wide area data transfer using the industrial CAN protocol
22.   Interfacing with RS485 for wide area data transfer Digital Scientific calculator by Interfacing  LCD (liquid crystal display) and Hexadecimal Keypad with AVR MCU.
23.   Adjustable Signal Generator (Sin, Cos, Smooth, Triangular, square) by Interfacing  GLCD (Graphical liquid crystal display), button Keys, and variable resistor with AVR MCU.
24.   RC5 code based, IR (Infrared) remote control sender/receiver, by interfacing IR receiver module unit and IR transmitter diode with AVR MCU.
25.   Obstacle detection using IR transmitter.
26.   Interfacing Barometer with AVR MCU for measuring barometric pressure and altitude.
27.   Interfacing RTC (Real Time Clock) chip (DS1307) for real time application.
28.   Speed control of DC motor using  PWM (Pulse width modulation)
29.   Interfacing 8-bit ladder network with AVR MCU for DAC purpose.
30.   Interfacing RS485 converter with UART serial interface for long area data transfer
31.   Interfacing AVR MCU with PC using RS232 converter and USART serial interface
32.   Digital Frequency counter/meter 1HZ – 4MHz
33.   Programming Smart-Card with high-security software algorithms using the AES and DES symmetric-key algorithm
34.   Storing Data using MMC/SD card in FAT23 format
35.   Resistance and Capacitance Digital Meter
36.   Wireless data transfer using IR 38KHz (Infrared) based on Ir-Data Protocol
37.   Wireless data transfer using RF 433MHz (Radio Frequency) based on FSK modulation
38.   wide area data transfer using the industrial CAN protocol for
39.   Digital to Analog conversion using 8-bit Ladder network
40.   Programming 32x8pixel LED-Matrix scrolling Display
41.   Interfacing with LM35 analog temperature sensor (-45ºC ~ +125ºC)




Also, some of the experiments were provided with Simulation using Proteus.


Posted on: September 26, 2009, 03:14:34 15:14 - Automerged
Here is the PCB design of the Kit.

Top Layer:


Botton Layer:


All Layers:


Schematic is coming...

[samud]

do u have the gerber file for PCB?

[wedo]

Yes Samud, I have the gerber files.

I will post here the schematic and PCB eagle files later, but first, I would post the design to be discussed by any interested people, so that we can all get benefit of the ideas and develop the design further.

If I give you the whole design directly, you will simulate the design without any idea about it. Sure you will have your own perfect kit and use it for develop your MCU project, but I'm looking here to develop Embedded hardware and software design skills, which are my specialization. Let's try to learn. We all have something important to offer.

By the way, this design is version.1, I'm working on version.2 which will be shared here as well very soon.

If you have any question about the peripherals and their connections, I will be glad to answer.

Wedo,

[Ichan]

That is a good PCB Layout, designed for double sided non pth DIY pcb, I believe you route it manually - not using autorouter.

For discussion people need the the schematic for sure.

-ichan

[wedo]

Yes Ichan, the PCB routing has been done by hand, Aurorouter has never been used in this design. It seems you have a good experience in PCB design to figure out that. 

Anyway, you will check the PCB.brd (Eagle) design file by yourself later.

Wedo,



Posted on: September 26, 2009, 09:30:26 21:30 - Automerged
The MCU Module:

The MCU has designed to be located on a separated module so that can be replaced any time by another proper MCU module (in case of damage, for example).

Here below is the MCU module schematic and PCB design.

MCU Module Schematic:


MCU Module Layout:


The design has considered Internal 8MHz/External 16MHz/RC oscillator, and RTC 32KHz oscillator.

EMC and EMI considerations has been taken in consider as well.

The peripherals schematic will be followed soon.

[SFx]

You are supported by a lot of set of interface standards, and why Ethernet is not provided?
In addition you can offer to install connector for GSM / GPRS / GPS module. e.g. Sim300.
Also, Now it is very useful to use ZigBee
Thank you for developed such an interesting card for debugging, I'll wait PCB files and schemes

[wedo]

SFx,

Thanks for your suggestion. Actually, there are thousands of peripherals, modules, and solutions in the world, I can’t setup all on one single board!

Ethernet surly is important, but it has complicated HW and a lot of components; GSM / GPRS / GPS modules are all interesting to be interfaced, therefore, the kit MCU pins have pulled-out and provided with pull up/down resistor (10K) with ability to activate or disactivate this resistor.
 
There are 50 I/O at the sides of the board in your Lordship. For instance: You can purchase an Ethernet module (anyone you like from any brand) and connect with SPI interface or any proper serial interface. The same for GPS module, most of GPS modules have UART interface, and so on.

Briefly, too much time spent before I got started designing this kit. I had a lot of idea about setup an Ethernet, TCP/IP, Stepper motor driver interface, etc…

The installed peripherals are the most important set for the newbie and junior learner.

[iphone]

Wedo,

Good progress.

Hope I can learn much more from you and this discussion.

I'm waiting ...

[Ichan]

I'll start to discuss:
1. I would add some 100n smd capacitor between pin 21-22, 52-53, 62-63, 64-63
2. No low pass filter for AREF?
3. VCC1 and VCC2 not connected yet?

-ichan

[wedo]

I'll start to discuss:
1. I would add some 100n smd capacitor between pin 21-22, 52-53, 62-63, 64-63
2. No low pass filter for AREF?
3. VCC1 and VCC2 not connected yet?

-ichan

Great! Here we go...

1-   100nF Decoupling Capacitors:
To reduce the EMI radiation (EMI reduction) and to prevent impulse noisy operation current, a 100nF capacitor should be placed as close as possible to the power pins.

For that reason our friend Ichan has suggested to place coupling capacitors next to the power pins.

These capacitors are already placed, they are at the sides of  the schematic, C3, C4, C6, C8, and C9.

Very important and interesting PCB design consideration references are in the below links:

AVR040: EMC Design Considerations
http://www.atmel.com/dyn/resources/prod_documents/doc1619.pdf
AVR042: AVR Hardware Design Considerations
http://www.atmel.com/dyn/resources/prod_documents/doc2521.pdf

2-   Low Pass filter for AREF:
Usually the AREF pin doesn’t required LPF (Low pass filter), because the reference voltage will be provided by an external Voltage reference source which is already has its own LPF. Moreover, there is no direct connection between the analog components and the VREF pin. We will come later to the VREF circuitry.


3-   VCC1 and VCC2 not connected yet:
Right. At the module they are not, in order to simplify the circuit. They are connected on the main board. More decoupling capacitors are exist on the main board.

Very nice suggestions. Let us suggest providing a reference for any incoming suggestion, I mean anyone can ask question, or suggest a better solution supported by a reference.

Wedo,

[goktug]

Wedo you have done a great job.
Thanks for your sharing...

[wedo]

Sorry for being late posting the schematic of the Main Board; my last days was very crowded!

OK…
Here below is the main board that hold the MCU Module (above).

1-   The MCU Module holder socket:



Posted on: October 11, 2009, 10:23:49 22:23 - Automerged
2-   A linear 5V Power Supply:



Posted on: October 11, 2009, 10:30:16 22:30 - Automerged
3-   The I/O expansion connectors and the Pull up/down resistors:



Posted on: October 11, 2009, 10:33:22 22:33 - Automerged
4-   Interrupts Switches, LEDs, Hexadecimal keypad:



Posted on: October 11, 2009, 10:36:23 22:36 - Automerged
5-   The programming Interface, STK200/300:



Posted on: October 11, 2009, 10:38:55 22:38 - Automerged
6-    The USART0 and USART1 Debugging Interfaces:



Posted on: October 11, 2009, 10:40:59 22:40 - Automerged
7-   20x4 LCD and 128x64 GLCD:



Posted on: October 11, 2009, 10:44:58 22:44 - Automerged
8-   Serial 24Cxxx EEPROM and RTC chip DS1307, I2C interfaces:



Posted on: October 11, 2009, 10:48:11 22:48 - Automerged
9-   Quad Seven-Segments Display:


Posted on: October 11, 2009, 10:50:42 22:50 - Automerged
10-   16x8 LED-Matrix Display:



Posted on: October 11, 2009, 10:52:40 22:52 - Automerged
11-   RS485 Interface:


Posted on: October 11, 2009, 11:02:54 23:02 - Automerged
12-   8-bit R-2R Ladder Network (DAC):



Posted on: October 11, 2009, 11:05:00 23:05 - Automerged
13-   RC5 Code based, Transmitter and Receiver:



Posted on: October 11, 2009, 11:07:33 23:07 - Automerged
14-   AT Keyboard/Mouse and MMC/SD card interfaces:



Posted on: October 11, 2009, 11:13:08 23:13 - Automerged
15-   The Basic Card and ASK Transceivers Modules:




There is more parts will be added soon… In the meanwhile, your questions are welcome.

[wedo]

16-   Analog Sensors Set: Linear Voltage, Temperature, NTC, Light, Single-Pin-Multi-Switch, and the analog voltage reference.




17-   Pressure/Altitude Sensor circuit:




18-   Speaker Output, 1-wire Temp Sensor, and Capacitance Humidity Sensor.




Posted on: October 12, 2009, 06:29:12 18:29 - Automerged
19-   USB interface and STK500v2 Programmer:





The design circuits are almost completed. There are the LAN interface which I handled in the new version of the kit, so we are not gonna post now.

I will start uploading the 'Experiments source code (Examples)' and the 'Experiments hands-on Manual soon.
P.S. The manual and hands-on course will be uploaded here are in Arabic language!

If you have any question about the design, please don't hesitate to replay!

[Ichan]

Nice!

With GLCD on board we can play EasyGUI with it    http://www.sonsivri.com/forum/index.php?topic=24804.0

-ichan

[wedo]

Yes my friend 'ichan'... Actually most of the peripherals on the board are supported.

Besides, the kit has two programming interfaces, STK200/300 and STK500v2, so you can handle in any GNU complier.

[wedo]

Der Friends,

I will start uploading the 'Experiments source code (Examples)' very soon...

Please hold-on...

Any questions about the schemtic?

wedo,

[charudatt]

I had a question about the programmers you have on board. Why two programmers and if you are using a ATMEGA8 then why use it with a FTDI chip. you can directly connect the ATMEGA8 to USB anyway, its going to be serial and not HV. If you have a MEGA128 and you mess with the fuse. Is there any provision for HV resetting. I am sure you are looking at the newbie angle and they are going to mess it up.

I feel MAX3232 would be ideal. But anyways, Both are pin compatible.

regards

[kigba]

Der Friends,

I will start uploading the 'Experiments source code (Examples)' very soon...

Please hold-on...

Any questions about the schemtic?

wedo,

Great work,
Can you upload Eagle files.

[wedo]

I had a question about the programmers you have on board. Why two programmers and if you are using a ATMEGA8 then why use it with a FTDI chip. you can directly connect the ATMEGA8 to USB anyway, its going to be serial and not HV. If you have a MEGA128 and you mess with the fuse. Is there any provision for HV resetting. I am sure you are looking at the newbie angle and they are going to mess it up.

I feel MAX3232 would be ideal. But anyways, Both are pin compatible.

regards

Thanks for your question!

There are two programmer on board, STK300 which can be connected to LPT port, and STK500v2 which can be connected via USB port.

The ATmega8 MCU is holding the STK500v2 USB firmware which is transfer data from UART to SPI interface which is very fast.

Sure, you can connect the ATmega8 directly to the USB without FT232R, and install another firmware that convert the USB frame to SPI frame, but the later will be very slow!

STK500v2 is compliable open-source programmer.

If you change the SPI fuse for any ATmega MCU, you have to use factory default file to get back that fuse on, which needs a programmer I have no information about for now.

I’m sorry I didn’t understand what you really mean by “. I am sure you are looking at the newbie angle and they are going to mess it up.�! However, the first step to achieve something is to fall down, then you can move forward with sure footed.

Thanks,

Posted on: October 19, 2009, 12:35:48 12:35 - Automerged

Great work,
Can you upload Eagle files.

Sure, I will upload the shematic and board eagle file, but later! I need to get real discussion a make sure the design is clear and open.

This design is open-source for everyone to have a new knowledge, and the later is come wih questions and deep discussion.

This is an education forum, let us take benift of it.

[charudatt]

Hello all,

let me add some of my points here for discussion , not sure, if it applies, if the design are in its final stage.
1. The PCB becomes too bulky, I mean too big to handle and move, Still not sure of its final design specs yet.
2. This design locks your possibilities to the experiment that you have foreseen.
3.  Too many DIP switches to fiddle around to get your configuration right for a given experiments.

IMHO, I would like to see the design modular,
1. A basic board with the programer, serial port, power supply and all port pins coming out via a 10 pin Box Header
2. Each of the Box header able to source 5V Power to connecting board.
3. Design modules that connect to this board to provide a newbie his experience with the experiment that's planned
4. Some basic module boards to interface like LCD, GLCD, Keyboard can be bundled along with this Main board.
5. The modular design offers great flexibility to replace at will , to your choice. With the above design, all things on the board (resources) get locked in for the board. But with the modular design, they can be swapped at will.
6. Not all connecting boards need to be DS (Double Sided) design. They could be SS (Single Sided) design, which could also bring down the cost.

I wished we discussed on this idea, if you find it reasonable.

regards


Posted on: October 19, 2009, 01:03:41 13:03 - Automerged
Hello Wedo,

What I meant to say was, that It is very easy for a newbie to screw up the fuse setting of the ATMEGA on board. And if he does that , is there a way to recover it ?

Again coming back to the modular approach, I would prefer the Programmer also to be outside. Just the HV Prog. Pins coming on a Box Header. The HV Prog. Pins will take care of the simpler SPI prog. available. Then you can have a wide range of programmer that can be connected to this board Serial/Parallel or STK200/300/500vxxx.

regards.

[wedo]

Hi,

Thanks for your nice post here!

let me add some of my points here for discussion , not sure, if it applies, if the design are in its final stage.

No the design still in prototyping stage. You are welcome to add.

1. The PCB becomes too bulky, I mean too big to handle and move, Still not sure of its final design specs yet.

The design dimensions are 36x22cm, it has been designed from the first stages for LABs which means the board should be fixed. We can consider another mobile design, but the later one will have less peripherals on board, in other hand, the extended space for this board make it easier for student to work with peripherals.
 

2. This design locks your possibilities to the experiment that you have foreseen.

I didn’t understand what you mean here, but the kit is extendable using the extended I/O connectors.

3.  Too many DIP switches to fiddle around to get your configuration right for a given experiments.

DIP switches are used for pull up/down resistors, I just count 6 DIP switches. They are important.

IMHO, I would like to see the design modular,
1. A basic board with the programmer, serial port, power supply and all port pins coming out via a 10 pin Box Header.
2. Each of the Box header able to source 5V Power to connecting board.
3. Design modules that connect to this board to provide a newbie his experience with the experiment that's planned
4. Some basic module boards to interface like LCD, GLCD, Keyboard can be bundled along with this Main board.
5. The modular design offers great flexibility to replace at will , to your choice. With the above design, all things on the board (resources) get locked in for the board. But with the modular design, they can be swapped at will.
6. Not all connecting boards need to be DS (Double Sided) design. They could be SS (Single Sided) design, which could also bring down the cost.

1,3,4,5- Some people like modular kits and some likes ‘all on single kit’. No problem with both.
2- The kit is already provided with 5V next to each I/Os connector.
6-We have a lot of wires here, so the DS board is requested. Furthermore, multi-layer PCBs can solve the EMI problems.
 

I wished we discussed on this idea, if you find it reasonable.

Sure, I would love too.

Best regards,
wedo[/size][/size]

[charudatt]

Cool, then, I have no further suggestions on this board. This board surpasses all my imagination. Congrats. Well I would reserve my opinion on the modular approach. 

Sorry, my apologies, I missed out on the Port Pins coming out. Yes I saw them later. I would suggest , stick to just one type of a programmer on board. Parallel Port is obsolete now a days and even Serial port is on its way. You could same some space and complexity.

Lets hear from others on what they say.

[usrrsr]

First of all thanks for great work. Really Appreciable.
Here are some comments

1. A linear 5V Power Supply:
   You can add a transitor across 7805 so that it can source much current may be with TIP122 2-3 amps. so we don't need any   
   additional power supply. See the attached image. I can give eagle files if you want.
2. Add another port headers parrelel to the exiting pins with vcc,gnd pins like what we did in attached schematic.
3. Add 74HC154 , 4 to 16 decoder.
4. Also you can think to add 12 bit ADC using MAX188 & 16 bit port expander using MCP23S17. I can give you eagle files if you are
    interested in.
5. Add Fuse with pcb mountable jack.
6. As per me there is no need to bother about the size of board, As this is advance experimental board and it is never recommended to
    use it for industrial use. In industrial board you must give only required functionality circut not even additional connectors or ISP
    headers etc.
7. Also add the commertially easily available Tx-Rx module (i have seen it somewhere on post - sorry for repetation) interface. Also
    note that output voltage given by most of the receiver module is not directly compactible with microcontroller (My experience
    taught me this). So if possible add comparator (using LM324 /LM339) at output stage of receiver module.
8. Add MOC 3043 based solid stage relay interface, IR pair interface if possible.
9. Add toroidal bead inductor inline with DC power in just before 7805.
10. Keep provision for adding external 64k ram (like 62512 - 64k,62256-32k) useful when large data storing required.
11. Add 2 external header for SPI commnication one will be with 3.3 volt power supply and another with 5 v power supply.
12. While writing the codes if possible use MikroC compiler, it has wide variety of redymade libs. and also MikroC compiler is available for
     PIC,8051 and AVR hence if a newbie learns any one out of them, with some littlebit additional reading he will e in position to code it
     for PIC and 8051 too. Isn't it amazing !

All this is suggestion however you and others may have different opinion on this.
Also post eagle files once finished.

regards

ulhas