next topic »

[on:]

Hi,
I have a TY-001 Vending machine.  I would like to incorporate arduino uno, a gprs/gsm module to vend products.  Any ideas on how best to implement this idea.

Thank you.

Regards

Keli

[Reply #1 on:]

Any ideas on how best to implement this idea.

One step at a time.

The first step is to define the requirements. Generally vending machines are controlled by customers inserting money.

[Reply #2 on:]

Thanks Paul

My interest has been triggered by those who have done vending via paypal and even based on a tweet.  Since we have money on our mobile phones more than we do coins, I believe, if we thought about it, we could vend based on a sms with a certain message.

Regards

[Reply #3 on:]

I don't see anything stopping you from the point of view of the vending machine, but you haven't explained how the payment occurs, or how the person paying knows the goods will appear at their machine (rather than some random remote one) or how the machine knows that the payment has actually been made before dispensing the goods.

If you want to set up an SMS based micropayment system then there are suppliers who can do this for you, but I can't really recommend trying to create your own solution for real-world use.

[Reply #4 on:]

The first step is to define the requirements.

An idea is not the same as a set of requirements. A set of requirements is not the same as functioning code. But, there is a progression from one to the next.

You have the idea, and at least a vague concept of the requirements. Now, it's time to flesh out the requirements. Think about this from the perspective of trying to hire someone to write the code for you.

What does the Arduino need to be able to do? Does it only receive text messages (Sell me A3), or does it send them, too (Item A3 dispensed).

How will the text message sent to the machine result in a bill being sent to the phone owner? My mobile phone doesn't have any money in it. I can't do anything to it to shake any money loose.

Certainly the Arduino, with appropriate shield, can receive text messages. It can, with the appropriate hardware, communicate with paypal to pry money out of the texter's account.

Whether you can write all the code to make this all happen, though, isn't clear.

[Reply #5 on:]

Your first objective has to be to get paid.
Therefore you need to investigate what hardware/software you will need to interface with systems that will provide you with payment. It also has to be very obvious and easy for the user to use your system.

In addition need to consider your profit margins. If you use gprs/gsm, and a payment system then how much will you have to pay for those services?

Security would also probably be quite a big concern. I guess vending machines are quite good at rejecting fake coins, they certainly reject enough of my cash. You will need to make sure somebody does not figure out how to make your machines pump out all their goodies and then post their hack on the internet.

[Reply #6 on:]

It would be extremely foolish for a consumer to entrust a vendor with credentials needed to access their Paypal account. There are suppliers who provide micropayment systems based on SMS (the payment would simply be added to the sender's phone bill) but this is not something that the casual DIYer can replicate - and if you try to bodge together a solution based on the mechanisms that are freely available to you (public access to payment web services, sending and receiving text or data messages) then IMO the only options open to you will leave either the buyer and/or the seller vulnerable to fraud.

[Reply #7 on:]

I had quite a bit of help from blog.bouni.de.

Now I'm left with interfacing with the sim900.  Most payments are done here via sms which means you don't have to worry about security.  It's handled by the carrier.

I appreciate your input.

Thank you.