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[ TERC VHS-1 Sun Photometer ] [ Manual TOC ] [ Back to Assembly Instructions ]

Getting Started

After you collect all the necessary parts and tools (see Parts List), you should be able to assemble the TERC VHS-1 Sun Photometer in a few hours or less. If you have previous experience building electronic circuits or kits, you may want to make modifications to the instrument. This is acceptable only if the distance between the roughened end of the LED and the sunlight port in the case is 6.5 cm and the diameter of the sunlight port is 7.0 mm. IMPORTANT: Be sure to collect all the necessary supplies and tools before starting. Place all the parts in a box so you will not lose any of them during assembly.

Prepare the TERC VHS-1 Case

The instructions given here apply to the specific video case described in the Parts List and illustrated in the drilling guide shown in Fig. 2. Other cases will also work if they are not too flimsy. But you may need to alter the position of the batteries and other items. Just be sure that the distance from the roughened end of the LED to the hole in the case and the diameter of the hole remain exactly 6.5 cm and 7.0 mm, respectively.

Check off each step as you proceed. And avoid mistakes by taking time to double check your work, especially BEFORE making holes.

CAUTION: Use appropriate safety procedures when drilling holes! Be sure to place the case over a wood block before drilling (unless you use a drill press with a hole for the drill to pass through). Hold the case SECURELY when drilling or it will spin. Although a drill is best, since the VHS case is very soft, holes can be formed with a sharp hobby knife. These knifes are VERY sharp! Use great care when making holes with a hobby knife! Avoid applying too much pressure or the knife blade may snap off!
  1. Refer to Fig. 2 and place the solderless breadboard inside the case as shown. Place one end of the solderless breadboard flush against the inside of the rigid side of the case. Slide the breadboard along the inside of the case until its upper side is exactly 7 cm from the inside of the front end of the case.
  2. When the breadboard is in the proper position, hold it securely and twirl a 3/32-inch drill bit in each of the four holes to mark drill guides in the bottom of the case. Check to make sure the breadboard was in the proper position.
  3. Remove the breadboard and drill a 1/8-inch hole at each of the four drill guides. Hold the case firmly while drilling. Don't worry about plastic shavings that remain attached to the case. We'll remove them later.
  4. Close the case for this and the following steps. The upper side of the case is the lid. Orient the case so the lid opens to the LEFT. This means that the flexible side of the case is to the left and the rigid side of the case is to the right. With the case oriented like this, place a piece of masking tape on the upper end of the lid to indicate the upper end of the case.
  5. With the case closed, use a small drill bit or scribe to mark drill guides in the center of the flexible side of the case 4 cm from the top and bottom edges.
  6. With the case closed, use a 5/32-inch bit or its metric equivalent to drill a hole at each of the two drill guides you just marked. Hold the case firmly while drilling. The plastic case is very soft, so drilling is easy. (Don't worry about plastic shavings that remain attached to the case. We'll remove them later.)
  7. Place an angle bracket along the rigid side of the top end of the case (see Fig. 3). With the bracket held flush against the shoulder extending from the bottom of the case, use the hole in the bracket as a template to mark a drill guide. The hole will be around 16 mm from the top end of the case.
  8. Repeat this procedure to make a second drill guide in the rigid side of the case 6.5 cm from the bottom end of the case (see Fig. 3).
  9. With the case closed, use an angle bracket to check the position of both drill guides. It is VERY important that the side of the bracket is flush with the lower edge of the case as shown in Fig. 3. This will keep the bracket from moving after you attach it to the case.
  10. Use a 5/32-inch bit or its metric equivalent to drill holes at the two previously marked drill guides.
  11. Mark drill guides centered 1.8 and 4.5 cm from the bottom end of the rigid side of the case.
  12. With the case closed, use a 5/16-inch drill bit or its metric equivalent to drill holes at the two previously marked guides. Hold the case firmly while drilling.
  13. Mark a single drill guide in the center of the bottom side of the case (Fig. 2). Check to make sure you marked the guide on the bottom end, not the top end, of the case.
  14. With the case closed, use a 15/32-inch (best choice) or a 1/2-inch bit or its metric equivalent to drill a hole at the previously marked guide. Hold the case firmly while drilling.
  15. Carefully remove any plastic that remains attached to the edges of any of the holes. A sharp hobby knife may be necessary.

    CAUTION: Use care when using a knife to cut away any remaining plastic!

    Note: Two more holes will be drilled later.

[ TERC VHS-1 Sun Photometer ] [ Manual TOC ] [ Back to Assembly Instructions ]

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