| ??? 11/20/06 07:22 Read: times |
#128290 - A little bird told me... Responding to: ???'s previous message |
Khurram Shehzad said:
I tried SIM card because I found one old SIM for free. But I cannot able to interface it with 89c51. Why not? What did you try? What were the problems? As you will see from the foregoing discussion, I had my doubts that this would be practical - it would be intersting to hear the experience of someone who's actually tried it! So I request you if any one can suggest any idea for cheep access-control system. As ever, your first step must be to clearly define exactly what it is that you want to achieve; you need to specify your requirements - in particular, what do you mean by "cheap"? Then you can start doing some proper, informed research... What's wrong with a simple, traditional, mechanical lock and key? You will probably have difficulty making anything cheaper than that! From the fact that you were considering relying upon one old SIM that you just happened to find kicking around, I guess that this is not a commercial project?! Probably the cheapest option is just to use a multipole connector, and rely on complex wiring inside it to complete the access-control circuit. No microcontroller required! A keypad should be cheap. Something like a Dallas iButton could be more secure; or a magnetic swipe-card, or RFID, or a "proper" smart-card, ... Fingerprint sensors are becoming "cheap" by some measures. I also tried 24c16 What did you try with it?! By the way: the spelling is "cheap". "Cheep" is what little birds do... |
| Topic | Author | Date |
| GSM SIMs | 01/01/70 00:00 | |
| Explain... | 01/01/70 00:00 | |
| We are fine | 01/01/70 00:00 | |
| Go straight to the Horse's Mouth | 01/01/70 00:00 | |
| What "Interfacing"? | 01/01/70 00:00 | |
| I'll answer for fun | 01/01/70 00:00 | |
| Big SIMs | 01/01/70 00:00 | |
| What "Interfacing"? | 01/01/70 00:00 | |
| but would you throw away all the radio part... | 01/01/70 00:00 | |
| Missing the point! | 01/01/70 00:00 | |
| Mute? | 01/01/70 00:00 | |
| Abbreviations | 01/01/70 00:00 | |
| cheep access-control system | 01/01/70 00:00 | |
| cheep access-control system | 01/01/70 00:00 | |
| Meaningless | 01/01/70 00:00 | |
| A little bird told me... | 01/01/70 00:00 | |
| Meaningless | 01/01/70 00:00 | |
| Not incorrect | 01/01/70 00:00 | |
| Not incorrect | 01/01/70 00:00 | |
| Not useful | 01/01/70 00:00 | |
| one way | 01/01/70 00:00 | |
I have a SIM in front of me; it has 13 contact pad | 01/01/70 00:00 |