Shield + small breadboard = crumboard

Crumboard shield is a prototyping shield designed for Jaluino. It embeds a small breadboard (thus the name, crumb-board...), two LEDs and two Push-buttons. This shield is useful to test new hardware designs. It's also a nice base to learn how to use Jaluino and get started with PIC microcontrollers, experimenting very basic tutorials such as famous "blink-a-led", and read input from a push-button. Definitely a must-have!

Schematic and PCB

Crumboard includes two LEDs and two push-buttons, as exposed in the following schematic:

Figure 1. Crumboard shield schematic

LEDs and push-buttons can be activated using jumpers JP1, JP2, JP3 and JP4.

PCB shouldn't be a problem to build. You can access 1:1 scale Crumboard PCB PDF format, on Jaluino SVN repository. You can also use Crumboard labels (as PDF version), to stick on the board, in order to get a nice board as shown on photos (TODO: link to labels howto tutorial).

Figure 2. Crumboard PCB

Building Crumboard

Crumboard is quite an easy to build. Since Jaluino is aimed to be cheap, we also give special attention in order to provide this prototyping shield with minimal cost.

Building PCB itself isn't explained here, the following step-by-step focuses on how to deal with integrating the breadboard. You can buy a small one that would fit within shield connectors, but it often the same as a standard one. Some standard breadboards can be cut to fit shield size, for lower cost...

	As first step, you'll have to find a breadboard like the one shown on the photo. It's a very common model. Be sure it can be cut.
	Start to draw a line with a black paper. This is where you'll cut the breadboard. You need to get a length of about 2,7" (6,8cm), just measure what you need on the board itself.
	Cut the breadboard, using a metal saw. Cutting is easy, just make sure it's straight.
	As shown on the photo (and as drawn with pen), cut on a holes row.
	Once cut, you should have something like this.
	Depending on your breadboard model, you may need to remove one power lines part. Usually, you have two of them, on the left and right. Keeping both may give a breadboard too large top fit within shield connectors.
	With one power lines part removed, breadboard will fit perfectly... Make sure to also remove the small remaining plastic part to get a clean surface.
	You're done, just stick it between shield connectors. Some breadboards have a sticky surface, but it not, just use some strong glue. Now the best for the end, you can build two crumboard with one standard breadboard ! Having multiple crumboards can be very useful when you work on multiple projects and design versions. Switching between them is easy: unplug a crumboard, plug another...

Using Crumboard

Crumboard can be used like any breadboard, but also provide LEDs and push-buttons to experiment inputs and outputs easily (TODO: links to upcoming Jaluino tutorials). This is an essential shield when getting started with PICs.

Crumboard can also be used to test rather complex designs, like this one prototyping a bluetooth device...

What is Styx ?

Styx is a shield allowing to use original Arduino shields with Jaluino. This is an intermediate shield to make two different worlds talk together. There's no magic behind this shield: pins from Jaluino PIC are arbitrarily mapped against pins from Arduino Atmega. Not all pins can be mapped. For instance, Atmel has often more PWM pins than PIC and, on the contrary, PIC often has more ADC channels than Atmega. So this arbitrarily mapping isn't perfect, but hopefully optimized and usable...

Schematic and PCB

Styx schematic is simple, it's just about mapping pins together...

Figure 1. Jaluino Styx schematic

While schematic is simple, PCB is more complex, despite the small number of components... Remember not using this image to build your PCB, as it may not be scaled correctly. This image is just here to give an overview. You can access 1:1 scale Styx PCB and labels, PDF format, on Jaluino SVN repository.

Figure 2. Jaluino Styx PCB

Building Styx

Since PCB looks more complex than one would think, Styx shield isn't so easy to build. You'll have to be careful with thin tracks. Styx is about plugging shield together, so also give attention while soldering pin headers: make sure they are as vertical with the board, and parallel between them, as possible. Else you'll get troubles while plugging Arduino shields.

Styx shield is more a mechanical challenge than an electronic one...

Figure 3. Styx plugged on Jaluino

Figure 4. Side view of Styx plugged on Jaluino. Pin headers on the left aren't perfectly vertical, making Arduino shields not easy to plug.

Using Styx

Using Styx is easy: just plug an Arduino shield on it... The challenge will be to find an Arduino shield compatible with PIC specifications. Theoretically, you could plug any Arduino shields. In practice, prototyping shields are good candidates, due to very simple electronics.

Figure 5. Jaluino, Styx and an original Arduino prototyping shield

Figure 6. Looks like Pise tower...

Figure 7. LED is blinking. Sweet...

Other more complex shields, even if usable with a PIC, will require you to write the program to drive it. If you're in the process of such a challenge, please keep inform us at Jaluino Group¹ !

Limitations

Styx shield allows to use Arduino shields. To be accurate, it allows to physically plug Arduino shields. Due to the resulting "Pise design", you may encounter problems when dealing with analog and PWM signals². Using complex Arduino shields (ie. not prototyping boards as previously shown) may require lots of work to adapt it, writing program on the PIC side.

These limitations obsviously exist. But fun is unlimited :)

Option 1: buy specific connectors

This first option may be the easier one, while by far the most expensive. Connectors issue isn't a new problem, Arduino has exactly the sames. So, if you search enough, you should be able to buy such female connectors with long pins, named stackable pin headers. Since there are quite specific, so is the price...

Just like Arduino, Jaluino uses two type of stackable headers: 8-pins and 6-pins. You'll have to get both types.

Figure 1. Vendors such as Sparkfun sell Arduino's specific connectors, for few bucks.

Pros are obvious: this is the simplest way to get your shield built. Cons are also obvious: it may not be the cheapest solution. No, not the cheapest... Also, by plugging/unplugging shields, such connectors will eventually get "tired", won't perform their job anymore and you may soon have to completely replace it...

Option 2: build your own specific connectors

Another option is build them by yourself. This is the cheap-way, something we rather like at Jaluino... So, how does it work ? Female connectors with long pins exist for IC, this is quite standard and easy-to-find connectors. Combining them with classical pin headers and you'll get nice Jaluino connectors !

Figure 2. Building your own specific connectors, with IC dedicated pin headers

The main advantage is the price: despite the greater number of pieces, since they are standard, the whole is cheaper than some Arduino's specific connectors. Also, if connectors on top get damaged, you can easily replace them without having to unsolder your shield and change others. Drawbacks might be top connectors may not get easily plugged on IC headers, or get removed unintentionally...

Figure 3. Home-made connectors in action !