Maximite Expander

What Is a Maximite?

The Maximite is a small and versatile computer running a full featured BASIC interpreter with 128K of working memory.

It will work with a standard VGA monitor and PC compatible keyboard and because the Maximite has its own built in SD memory card and BASIC language you need nothing more to start writing and running BASIC programs.

The Maximite also has also 20 input/output lines which can be independently configured as analog inputs, digital inputs or digital outputs. You can measure voltage, frequencies, detect switch closure, etc and respond by turning on lights, closing relays, etc - all under control of your BASIC program.

The design is free and open source including the software and BASIC interpreter. And all this is powered by a single chip which costs just US$8.44.

The Maximite was developed by Geoff Graham and full details can be found at Geoff's website here

What Is a Maximite Expander?

The Maximite Expander is an add on board for the Maximite that provides isolation and easy connection for 10 channels of the Maximite's I/O pins.

This is the big gun of the Maximite Expander modules. A Smaller "Modular" series of modules is also available. More information can be found here. Maximite Modular Series

Click here to purchase

It features;

• 10 channels each of which can be configured as Digital Input, Digital Output or Analog Input (selected by a jumper).
• 2 boards can be cascaded to access all 20 of the Maximite's I/O pins.
• Full isolation and protection for the Maximite's PIC32 processor.
• Variety of configurations depending on how the board is loaded.
• Input voltage isolation, easily allowing interfacing to circuits that require or supply more than 3.3V (eg common 12v circuits)
• 2 DPDT 8A relays that can be configured for any channel
• Simple ribbon cable connection to the Maximite.
• 2 boards can be stacked to reduce space.
• V2 board has RS232 hardware to support the future serial communications.

Schematic Diagram

MaxIntV2.pdf V2 Schematic

As it can be seen from the schematic there is nothing particularly revolutionary about the circuit, however I have endeavored to make it a flexible as possible.

At this stage I am planning to make the PCB available, so people can construct it with only the components and channels they need. or you can buy a full kit of parts. 

Note: the V1 board is no longer available.

V2 Expander

I have just finished the design and sent to manufacture V2 of the expander.

This version fixes a couple of layout issues and also adds the hardware for RS232 for use when the Maximite firmware is upgraded to support serial communications.

The cost of these boards on their own is $30AUD + shipping, and I have decided to also sell kits with all the components to fully populate the board.

The price of the full Kit including the board is $65AUD + Shipping. This will get you all the components, terminal blocks and connectors to fully populate a V2 10 channel board.

Also this production run is for a limited quantity, so if you are interested, you can order now.

Click here to purchase

Enclosure

 The board was designed to fit into a specific metal enclosure made by "Inner Range" and available through "Central Security Distribution" called "IR Small Enclosure".

This enclosure is actually one of several made by Inner Range to house their alarm products, and as such is very suitable for mounting on a wall near the item you wish to interface with. It has all the appropriate cable entry and management bits to make the wiring neat and easy. You can even add a tamper swith if you wanted to.

In addition the enclosure also houses a 2A battery backed power supply that allows the whole system including the Maximite to function for a considerable amount of time on a standard 6AH alarm battery.

More pictures and information is available here .

Assembly Instructions & Circuit Description

Assembly Instructions are included with the kit and an online version can be found Here 

Future Plans

I am considering making a couple of other variations of the expander.

The 10 channel version is quite a big board, and so I am thinking of producing a 4 channel version with 4 relays & RS232.

I am also considering the same 4 channel board with RS485 so you can network Maximites and monitor/control stuff from different locations, all reporting back to a central Maximite.

If you have any interest in these ideas, let me know as the design will be dependent on interest.

How to buy

If you wish to purchase one of my expanders click the Link below. 

Click here to purchase

Contacting Me

I will be adding to this page frequently over the next few days & weeks, so check back regularly.

In the mean time if you would like more information on the Maximite Expander, you can email me at maxexp@hamfield.com.au

Regards

Rohan Hamer

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