Ronja Twibright Labs

Building Ronja Hertz

Building Ronja Hertz

INFO We are going to build airwire hertz. It's a metal shielding box with a lid, with holes, cable grommetg and wire nuts and airwire electronics circuit inside.
Gallery[1680] Gallery[1681] Gallery[1682] Gallery[16af]

Soldering the bottom

Solder one lid to the case so that the case has a bottom. Solder the lid everywhere along the length its edges, from inner side only.

(Note: ignore the holes in the picture, I just don't have the right photo without holes.)


Contact flaps

  • Cut rim of the free lid to make contact flaps using tin scissors. Make 2 cuts on shorter side and 3 on longer one.
  • Shape the contact flaps so every flap has a good contact with the box that every flap is springed against the case when the lid is closed.

(Note: ignore the holes in the picture, I just don't have the right photo without holes.)

INFO There are two possibilities how to drill out the box. First one is using a calibrated printer, printing out a template and gluing the template on a tin. The second one is measuring everything by hand.
Postscript / PDF / EPS / BIG png / DXF (qcad)

Option 1: Drilling through a template

Print out this template and glue on the tin box.

Drill out holes on the template. Use the wire nut as template for it's mounting holes. During drilling use the M3 bolts and possibly also nuts to hold down the nut in already drilled holes. After drilling, soak the template off in water and throw away.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Option 2: making the box with manual measurements

Make the box according to the plan:

  • Use hard stylus or thin nonporous surface marker for drawing lines.
  • Use square for maintaining perpendicularity and centre punch for making centres of holes.


Install two 4mm grommets into the 6mm holes.

Note: the picture is of an almost completed Hertz

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Making L stubs

Make 2 L-Stubs according to the picture. Cut also 2 20mm long straight bare pieces from the same wire.

Gallery[169c] Gallery[169d]

Installing wire stubs

Install 2 insulated wire stubs into the grommets.

Mounting the wire nut

Mount the wire nut. Wrench is 5.5mm. Use M3x15 bolts and M3 washers and M3 nuts and tighten.


Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Color bands

Apply color bands with shown colors made from duct tape.


Insert LEDs into the box. Glue it down using thermal glue pistol.
INFO We are going to solder an airwire construction. All IC's will be glued down on their back. The interconnections will be soldered using a hard wire, solder and rosin flux. A transformer soldering iron (the one with the loop) or regulated-temperature iron is used for this.


Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Placing key components

Place key components according to the drawing:

  • U1, U2, U3, U4
  • J1, J2 (switches into holes)

Glue down chips on their back and write their type on a small sticker which then stick on them.


  PostScriptPostScript + Gzip PDF
Color Dark hertz_01.pdf
Light hertz_00.pdf
Small hertz_02.pdf
B/W Dark hertz_11.pdf
Light hertz_10.pdf
Small hertz_12.pdf
hertz.sch (gschem) Component lists Seznamy součástek


Solder in all the parts according to the schematic in this order:
  • IC blocking capacitors: C1, C2, C3, C4, C10, C11, C13, C14
  • Other blocking capacitors: C5, C6, C7, C8, C9
  • Remaining wires and passive component interconnections within one IC case
  • Remaining wires and passive interconnections going from one IC to another

Correctness check

Take the Hertz and inspect it completely.
  • Left-out components
  • Left-out wires
  • Wires leading somewhere else
  • Correct values of passive components
  • Correct IC types
  • Correct orientation of IC's
  • Correct orientation of diodes.
  • Correct orientation of polarized capacitors
  • Correct SW1 and SW2 connections (be sure they're not swapped)
Postscript / PDF / EPS / BIG png / SVG (Inkscape)


Print out the Hertz label. Stick the large label on the outer side of the lid and fill in. Stick the small label on top of the box (where wire nuts and switches are).

Print out the small schematic (see the Soldering section above) and glue on the inner side of the lid. Cross over any component that is replaced by an equivalent and inscribe the true equivalent type.

An expected information missing here?