Voting will decide who will succeed Olusegun Obasanjo.
Anyone trying to rig or tamper with Saturday's presidential elections in Nigeria could be caught out by a team of volunteers armed with mobile phones.
The Network of Mobile Election Monitors (NMEM) will use SMS to feedback their observations to a central computer hub.
The collected text messages will then be passed on to other monitoring groups and authorities including the EU.
NMEM hopes the system will stop fraud, especially in areas considered too dangerous for other groups to enter.
"We want to set a precedent," said Emauwa Nelson of the Human Emancipation Lead Project, a Nigerian NGO that helped set up the project.
"We want people to know that if they are trying to rig the election, there could be someone behind them and that person may send a text message saying what happened."
Voting is due to take place on Saturday to elect a new president to succeed Olusegun Obasanjo.
NIGERIAN ELECTION 21 APRIL
60m registered voters
120,000 ballot boxes
360 House of Representative seats to be elected
109 Senate seats to be elected
24 presidential candidates
Main contenders: Atiku Abubakar for the AC, 60 years oldMuhammadu Buhari, ANPP, 64Umaru Musa Yar'Adua, PDP, 55
Polls open at 0800 (local time) and close at 1500
To avoid a run-off, a candidate needs the highest number of votes overall and at least 25% of votes in 24 of the 36 states
It is the first time since independence in 1960 that power is being transferred from one civilian president to another.
The outgoing leader has urged election officials to prevent rigging.
"The world is watching us and we cannot afford to disappoint ourselves, our friends and the world," said Mr Obasanjo.
European Union observers are in Nigeria to make sure that the vote is fair and legal.
NMEM has been set up independently of the EU to allow ordinary citizens to take part.
"It allows everybody the chance to be part of this process," said Mr Nelson.
"By monitoring with SMS we can get a true picture of what happens."
The system takes advantage of Nigeria's 30 million mobile phone users.
The volunteers, all voters themselves, will be able to text observations to 0808-4032739.
The outgoing president has urged there to be no rigging
Observations from more than one volunteer in each area will be cross checked to make sure they are accurate.
NMEM is using a free system called Frontline SMS, developed by programmer Ken Banks, to keep track of all of the texts.
Originally developed for conservationists to keep in touch with communities in National Parks in South Africa, the system allows mass-messaging to mobile phones and crucially the ability to reply to a central computer.
It has already been used in countries such as Zimbabwe as a way of bypassing broadcast restrictions and distributing information to rural communities.
In Nigeria the system will be used differently.
"They're not using it to broadcast messages, they're more interested in how it can bring information in," said Mr Banks.
The collected information will then be sent to monitoring groups and the EU observers.
NMEM does not know how many people will take part but are confident that the system will add an extra layer of transparency to the Presidential and other elections.
"This will help to stop rigging and give Nigeria the chance to have better elections in the future," said Nelson.