When you want to hide something....what are the aspects you should consider?
Take a step back and think like a burglar! :-)

1. Where is the most likely place to hide your valuables? your bedroom??? yes..that is the most likely place...btw..how many of you hide there ?? So avoid all likely places!!!

2. The burglar...will not have much time..so do not hide in places he might discover!.... he will start throwing things this way and that way...throwing your clothes off the shelves...checking your shoe boxes...under the bed....under bed side table....you know....watch the movies....they will give you some ideas....unless of course...you have a live in thief...or close acquaintance...who knows you...visits you and knows how to do a slow and through search when you are not there...perhaps when you ask them to house sit...baby sit...( this is just an assumption...I'm not accusing your friends and family or telling you to suspect them....just trying to cover all aspects!)

3. Your valuables should not be in a place where he/she can stuff under the shirt....to later take home and break open...in case it has a lock.

4. It should definitely have a lock! If your burglar finds your secret place...why make it easy for them to access it!
It's better to have a lock that is invisible outside... if anyone sees a lock...it's the obvious conclusion that all valuables....will be behind lock keys for added security .

5. Your Valuables should not be in place where your parents or spouse or even say your day help might accidentally throw away or give away. Imagine your mom giving away some old stuff of yours....or lets someone borrow a book(which happens to be your secret stash book! oh horrors!

6. Finally...it's better to always have a dual purpose for your secret hiding place. It's something you actually use daily...it's in plain sight...it's a normal everyday household item...which nobody will ever suspect...and it's something you can make...without getting outsiders to make ....thereby loosing the secrecy.

Well....have I covered all aspects?? if I haven't please let me know :-)
keeping these ideas in mind..and the fact that some live in rental apartments so you cant break in the wall for in built hidden holes ....I came up with this secret dual purpose furniture.
Hope it helps you all!

Step 1: Wood and the Lock!

I know...most parents in US would have heard of these locks ...it's the magnetic locks...It's invisible from the outside...thereby not spoiling the look of the furniture.
There are most likely other locks as well...perhaps some that is electronic..and have coads and stuff....but....I'm not that advanced in my electronics!
well...see what works for you...In my case I went for the kids magnetic locks.
for wood i used most of my scrap wood ...I only bought 2x2's for legs
Sponge too I used scrap....but if you are buying 2" thickness would do nicely.

Step 2: The Chair Frame

I used plywood that I had to make the side panel shape. Your measurements can vary according to your preference. I wanted a broad seat so I took 17". and a height of 10". The rest I cut according to the size required..as i used scrap wood the various thickness differed...therefore your couldn't give a specific measurement. Please check pictures to understand what I mean :-)
Once your make the outer frame...make an inner frame too for the legs and secret compartment.

Step 3: Upholstering

cover the side panels with sponge first. Then glue in the seat curving to the bottom. I stapled at the bottom...to hold the curve...if you want a square...just cut. Once it's over...I used batting to cover the back and all around as i didn't have enough sponge to cover the back...but as it wasn't necessary...it was no fuss :-) the batting took care of it. Later I used white fabric to smooth it out.
You can staple your main fabric too if you like...sewing on the main panels only. I wanted a removable cover..... so the next step is if you want that too!
flip your chair to the side and draw a block of the sides...cut fabric according to shape.
Then place right side of fabric up and place around the chair and tuck. mark where it goes in and pin and tack it.
Now place the wrong side of same fabric on chair. make sure the line you tacked goes to the proper place ( I'm not sure what to call that place...just check pic!)
Pin all around the side panels too. Once you are satisfied with the fit...remove and sew along the pinned area. Try it on in the right side...see if it fits perfectly to your taste.
Flip the chair to the underside and sew a broad hem so you may pass a cord to tie up. Done

Step 4: The Legs and Secret Panel

I wanted the seat height to be an overall height of 30". So as the seat was 4" high..I cut the legs 26". screw in the legs to the inside frame. For the supports measure the inside and cut 2 slats of that size and 2 about 1" longer. Measure 10" from ground . screw in the longer slats to the legs. then drill pilot holes and screw in the shorter slats. do not use glue yet as you will need to remove the legs to fix the panel under.
flip the legs over and draw the shape on a wooden panel...cut accordingly. Do not fix till end as it would be difficult to fix your lock.
Fix the magnetic lock according to instructions...i fixed mine to the chair and the inner frame. Test the lock. my lock was placed so that the key would have to be in the center. I added a block to the inner frame to add the other piece.
As it would be impossible to show pictures of the lock working after fixing the panel...I've taken pictures to show how it works before fixing the panel.
Now that you are happy..remove legs and fix the panel with glue and screws...sand all over and stain to your preference :-).
fix your chair and tighten the cord...the snug fit and cord and lock holds the bottom section securely.

Step 5: Enjoy!

hope you enjoyed this instructable...my kids loved sitting on it :-) . it was so wide sometimes two of them sat on it!

I have added this to the secret compartment contest...so please vote once it's accepted :-)