BBC-Buggy Upgrades Log
Made a support arm for the BarCode/Line sensor.
Four millimetre ply, 15mm wide, 50mm between centres and 65mm loa, sanding sealered and sprayed black.
Mounted to the RHS axle block using the hole in the block and an M4x30 screw with 'O' ring and nyloc nut.
I cross drilled the inboard end of the hinged block to take a countersunk M4 screw and used another 'O' ring and nyloc nut. The 'O' rings provide spring in the joints and allow the joints to be held firm but easy to move.
At the inboard end of the arm, underneath, there is a 15mm dia 4mm ply spacer to lift the arm clear of the bumpers.
A problem with drilling the block was the black plstic retainer in the end of the block is held in by a steel shaft and drilling severed it and it the black plastic part fell out! I cleaned up the end to clear the M4 screw, held it in place in the end of the block and cross drilled through 1.2mm dia. Then pushed in a short length of 18swg brass wire to hold the black plastic part in place and centre punched both ends of the wire to stop it sliding out of the hole. Now good and strong again in case I want to mount the unit elsewhere and the grooves will still take 4mm rods.
Made an Arduino interface to run the BBC-Buggy.
See BBC-Buggy.ino for pin connections.
The shield just routes the Buggy 20way umbilical to the Arduino pins, the V+ supply, and the output from a 7805 5v regulator. Also it has a header for a FTDI USB/Serial adapter with the serial lines routed to Arduino pins 0 and 1.
I wrote a control program the for BBC-Buggy in Beta basic running on a Sinclair Spectrum which allowed line following, heading towards light or dark.places and exploring and mapping the locations of obstacles using the two front bumpers.
Added two LDR eyes to make it easier to head towards a light, they use the same circuit as the stock LDR seen by the left hand pillar. Using two eyes the Buggy instead of having to turn until the brightest direction is found has only to turn in the brightest direction - if the left eye sees more light then turn left a little and vica versa and if both eyes register the same amount then head straight forward.
The eyes can be seen just below the top rail, are built on two pieces of perf. board, held in place with sticky pads on the back of the top rail and are plugged into Ch2 and Ch3.
Made a connector box to link the Research Machines buggy interface to a Spectrum I/O module. The 25D connects to the RM cable and the 16pin DIL sockets are to my Sinclair Projects standard.
D0 1 16 5v
D1 2 15 5v
D2 3 14
D3 4 13
D4 5 12
D5 6 11
D6 7 10 0v
D7 8 9 0v