Imp and limited pins


Please forgive me if somebody has already asked this question. I’m 24 hours into imp!!!

I have a few projects I want to try out with the imp:

First is a simple temp/humidity sensor posting back to a web service. Seems pretty simple.

Second I want to make a clocking in/out system that uses an RFID reader, some sort of display (LCD perhaps) and a key pad. This sends clocking in/out to a web service . This where its a little tricky as there isn’t many I/O pins on the imp. Is the general way to get round this to use the imp as the wifi/Internet/cloud module and use a serial link to a micro controller, for example arduino, to manage to I/O?

Thanks in advance.

The imp is quite a bit more powerful that it might seem. If for some reason you run out on the imp001, the imp002 has 12 pins. There are a number of projects and code floating around for temp/humidity projects. I like thermocouples, so you can find my projects using the Adafruit 31855 breakout here and on GitHub. Searching GitHub for Electric Imp will get you a lot of code examples.

As far as RFID, I don’t think anyone has created code for the Adafruit breakout, but there is an Electric Imp reference board called the Olive that is soon to be released. I don’t know of anyone else who intends to make the board, but I will be, so watch that thread when it is released. I am also currently producing some of the Amber boards with imp002 modules if you are interested in those. If everything goes well there, I’ll likely make a few available on Ebay.

I’ve been doing LCD over serial with the Sparkfun serialLCD board… I think the Adafruit version is on backorder, and it works well. There is code for it on the Electric Imp Github repo, and mine “joel-wehr” I think.

Dig around… there is a ton of code, examples and projects out there. The Electric Imp rocks… enjoy!


I have been using the ID-20 RFID reader and it is essentially a single serial port. I have used it with Arduino and the Software Serial library.

The biggest issues I have had are keypad input. I have been using LCD for output and a matrix style keypad (which I don’t particularly like - it takes up stacks of pins, but I’m sure there is an I2C that can manage that for me).

Ideally I would prefer some sort of touch screen but there’s a bit of a ‘learning curve’ for me! :wink: Any suggestions would be welcome.

For the temp/humidity project (remote server/switch room/cabinet monitoring) I was going to simply hook up a DHT-22, used them before and they aren’t too bad. :slight_smile:

The imp should be delivered today so I’ll have a good play tonight!