The joys of making a small robot or a crystal radio set have long eluded those who can’t get past Step 2 in the instruction manual.

But now, Web-based instructions - often designed by hobbyists - are supplementing the often-confounding directions that come with handson kits.

Bloggers who tinker are creating interactive tutorials, descriptive videos and step-by-step series of photographs that make it easier for nontechies. Web sites like Evil Mad Scientist, AdaFruit and iFixIt also offer tools, components and kits, many aimed at beginners.

“We’ve moved from the lonely tinkerer to the social tinkerer who can share ideas,” said Dale Dougherty, editor and publisher of Make magazine, which sells kits, related books and tools.

Online communities have sprung up in which people help one another, adapting and explaining the instructions so they are clear even to novices.

Scott Heimendinger, who blogs about food at seattlefood geek.com, created a set of online instructions after he made a sous vide immersion cooker for $75 by using off-the-shelf components, rather than buying one for $1,200. The appliance is used to slowly cook food sealed in plastic and immersed in water at controlled temperatures.

He took photos of the process . “With every photo, you add information,” he said. “ This takes away a lot of the ambiguity.”

He tested his instructions on the Web, refining them in 15 versions with the help of reader feedback. “In the past, I would have no idea how well the instructions work,” he said. Now, “I have a dialogue.”

Some readers have adapted his design to control deep fryers, slow cookers and smokers.

Margaret Honey, president and chief executive of the New York Hall of Science, says she hopes the Web trend can also encourage children’s interest in science and engineering.

She singled out BigShot, a kit and a companion Web site that teach young people how to build a digital camera.

“You are building a complex tool,” she said, “but you are also learning the science.”

BigShot was created by Shree K. Nayar, a professor of computer science at the Computer Vision Laboratory at Columbia University in New York. The kit, now in prototype , divides the building blocks of the camera into fewer than 20 components.

The online steps for assembling the camera are broken down into a detailed series of photographs and text. A separate section, with interactive graphics, explains underlying principles of mechanics, electromagnetism, power generation, imaging sensing, image processing and optics.

The next step will be bringing the project to market, Dr. Nayar said. “But not as a toy,” he said. “It’s an educational kit for learning.”