Fun and challenging product design project: Who will step up?

Greetings, I am CTO for a high-growth social enterprise called Off.Grid:Electric. Our mission is to light the unlit areas of the world, and we have started with East Africa. We are 3 American entrepreneurs who have moved to Tanzania to set up the business, and we already have several hundred customers in our first pilot rollout. We are now refining the missing bits and pieces of our technology stack. We offer energy services that are affordable for the 80% of the population that lacks access to the electrical grid (or cannot afford the expensive connection fees). The grid in many of these countries is very expensive and unreliable.

The way we do this is to deploy the most robust DC based (Edison's revenge) small scale solar systems (5 to 120 watts), with lithium batteries and integrated power electronics, integrated with the most efficient appliances in the world (our LED's are over 100Lm/watt, our radios draw 2 watts, Tv's 15 watts).

Now for the challenge: We offer our energy systems installed in customers homes as a fee-for-service model. The way this is accomplished is through mobile phones (there is currently 80% mobile phone coverage). Our customer sends us a payment (through an agent or directly through a mobile money platform) and we send them a code. This code is entered into our device (via 3x4 keypad with small 16x2 display). The numeric code is decrypted via internal logic on MicroChip controller and it unlocks device for a period of time correspondent with the payment amount.

We have a prototype capacitive keypad with 16x2 LCD. The firmware will use DES level3 and DUKPT. We are not electronics experts, and we are a start up company with a limited budget so I am putting out a challenge to electrical engineers and designers to come up with creative solutions. The winning idea will receive a prize, be posted on our website and have the opportunity to make a difference in the lives of hundreds of thousands of hard working African families that currently use Kerosene and disposable batteries for lighting and phone charging.

WHat we need is a low cost/durable keypad and LCD with a micro controller that can manage the code decryption and LCD messages. Our eventual goal is a $5-$7 piece of hardware. The issue we have is the costs are still too high on the BOM. As long as it is durable and has decent environmental resistance, we are open to all ideas! Thanks for reading about our exciting project, and I hope to find our jewel of an idea on Arduino Forum!

I guess the problem you have here is production costs. The per unit cost can only come down f you are going to be ordering very large volumes of these devices.

How many do you think yo may be requiring per batch order.

The design is not problematic, the hardware is out there if yo are prepared to make compromises on functionality over cost.

I have sent you a PM with my details in it.

I take on start up projects from time to time and an old good friend of mine was working on the water issues in Africa before he died a few years ago and so I am willing to donate my time to help.

Cheers Pete.

I would like to help, I am in Cape Town, and while not a " programmer" , I can usally come up with simple lateral thinking solutions.

I already have a vague idea for simplifying the display. PM me if I can help ( time is sometimes tight, I am also trying to help rhinos , and make a living :-)