Coordinated Construction Smart Parts

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A SolidWorks representation of the smart part, without the beacon chip installed.

The smart parts are small, 3D-printed pieces. In their base (which attaches to a construction part) they have a power regulator and a battery. On the other end (which matches the grasper on the robots) they have an infrared beacon which transmits information about the part.

Contents for This Page

Recharging the batteries

A close-up of the 3.7V LiPo batteries that we use.

The small batteries that the Smart Parts use are single volt 3.7V polymer lithium ion batteries. They are rechargeable (so don't throw them away!) but if their voltage drops too low they cannot be recharged.

Charge the batteries by hooking them up to the charging station and setting it to 3.7V (single cell). The data sheet for the batteries indicates that the max charging rate is 0.2A, but we have been able to charge them up to 1A with no problems.

If the charging station indicates that the voltage is too low, throw the battery into the technocycle bin (not the trash).

Reordering Regulators & Batteries

A close-up of the AnyVolt Micro regulators that we use. They have the white label as shown when they're new, but you have to remove it to change their voltage.

The batteries are cheap and easy to find. In the past we have ordered them from BatterySpace.

The AnyVolt Micro regulators are a little bit more expensive, and for a while it seemed that they had been discontinued. We were able to order more from HVWTech. When using the regulators, always be sure to put the batteries in with the correct polarity. Hooking it up the wrong way, even for a second, will fry the regulator - a $20 expense, assuming that you can still buy them.

Printing more parts

The SolidWorks files for the parts can be found in the SolidWorks folder in the repository. For more information on printing see the page on the FDM 3D Printer.

Installing the IR Beacons

Digital installation

Installing the IR beacons is a two-step process. First, you must connect them to the AVR Amtel STK500. This is done with a cable that plugs into a small port on the underside of the board. You'll know if you've plugged it in correctly if the green LED on the beacon turns on (assuming that the Amtel board is on). The serial connection on the board should then be connected to the serial port on your computer - not through a USB adapter.

The (hopefully Linux) computer that the serial cable is plugged into then needs to run some files in the "fastener" folder in the repository. First, edit fastenerState.c and set the fastener message (around line 26) to either T or C, depending on if the beacon is going to be for a truss or connector, respectively.

Then run:

> make clean
> make
> make burn

If all goes well, you should get a success message (and an exit code of 0) and your part has been updated. It is probably a good idea to draw on it in either blue or red so that you know which kind of part it is.

Physical installation

The underside of the beacon, showing how the wires should be soldered from the regulator: + to Vout, - to GND. Click for a larger picture.

Before soldering anything, it is important to set the regulator to the correct voltage. To do this, hook up the Vin and GND leadsto a battery, and connect a voltmeter to the Vout and GND leads. If the regulator is new, it will probably read somewhere between 7-9 volts. On the underside of the regulator, use a flathead screwdriver to turn the small copper set screw (CW increases, CCW decreases). Try to get the voltage as close to 5V as you can.

You will also need to solder a 2-pin header to the regulator so that the leads can reach the batteries. Bend the leads down so that they are in the correct orientation. See a previously built part to see what it should look like.

Cut wires to connect the beacon and the regulator. They should be just a little bit longer than are required to connect them inside the part. Solder the wires to the beacon as indicated in the picture. Fish the wires down through the part, and then out the bottom. Connect the wires to the power regulator on the leads marked GND and OUT. Now, slide the power regulator in, and slide the beacon up and into its position at the top of the part. Superglue can be used to keep both in position, although it is not required.

See Also

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